Media coverage of climate change

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Media_coverage_of_climate_change 

 

Global warming was the cover story of this 2007 issue of the liberal-leaning feminist Ms. magazine

Media coverage of climate change has had effects on public opinion on climate change, as it conveys the scientific consensus on climate change that the global temperature has increased in recent decades and that the trend is caused by human-induced emissions of greenhouse gases.

Climate change communication research shows that coverage has grown and become more accurate.

Some researchers and journalists believe that media coverage of politics of climate change is adequate and fair, while a few feel that it is biased.

History

This 1902 article attributes to Swedish Nobel laureate (chemistry) Svante Arrhenius a theory that coal combustion could eventually lead to human extinction.

 

This 1912 article succinctly describes the greenhouse effect, focusing on how burning coal creates carbon dioxide that causes climate change.

Media attention is especially high in carbon dependent countries with commitments under the Kyoto Protocol. The way the media report on climate change in English-speaking countries, especially in the United States, has been widely studied, while studies of reporting in other countries have been less expansive. A number of studies have shown that particularly in the United States and in the UK tabloid press, the media significantly understated the strength of scientific consensus on climate change established in IPCC Assessment Reports in 1995 and in 2001.

A peak in media coverage occurred in early 2007, driven by the IPCC Fourth Assessment Report and Al Gore's documentary An Inconvenient Truth. A subsequent peak in late 2009, which was 50% higher, may have been driven by a combination of the November 2009 Climatic Research Unit email controversy and December 2009 United Nations Climate Change Conference.

The Media and Climate Change Observatory team at the University of Colorado Boulder found that 2017 "saw media attention to climate change and global warming ebb and flow" with June seeing the maximum global media coverage on both subjects. This rise is "largely attributed to news surrounding United States (US) President Donald J. Trump's withdrawal from the 2015 United Nations (UN) Paris Climate Agreement, with continuing media attention paid to the emergent US isolation following through the G7 summit a few weeks later."

Media coverage of climate change during the Trump Administration remained prominent as most news outlets placed heavy emphasis on Trump-related stories rather than climate-related events. This shift in media focus is referred to as "Trump Dump" and was shown to peak in times when the President was most active on Twitter. Just in the year 2017, the word "Trump" was mentioned 19,187 times in stories covered by five of the nation's biggest press accounts, with "climate" being the second most frequent word.^[15]

In a 2020 article, Mark Kaufman of Mashable noted that the English Wikipedia's article on climate change has "hundreds of credible citations" which "counters the stereotype that publicly-policed, collaboratively-edited Wikipedia pages are inherently unreliable".

Common distortions

Factual

Scientists and media scholars who express frustrations with inadequate science reporting argue that it can lead to at least three basic distortions. First, journalists distort reality by making scientific errors. Second, they distort by keying on human-interest stories rather than scientific content. And third, journalists distort by rigid adherence to the construct of balanced coverage. Bord, O'Connor, & Fisher (1998) argue that responsible citizenry necessitates a concrete knowledge of causes and that until, for example, the public understands what causes climate change it cannot be expected to take voluntary action to mitigate its effects.

In 2022 the IPCC reported that "Accurate transference of the climate science has been undermined significantly by climate change countermovements, in both legacy and new/social media environments through misinformation."

Narrative

According to Shoemaker and Reese, controversy is one of the main variables affecting story choice among news editors, along with human interest, prominence, timeliness, celebrity, and proximity. Coverage of climate change has been accused of falling victim to the journalistic norm of "personalization". W.L Bennet defines this trait as: "the tendency to downplay the big social, economic, or political picture in favor of human trials, tragedies and triumphs". The culture of political journalism has long used the notion of balanced coverage in covering the controversy. In this construct, it is permissible to air a highly partisan opinion, provided this view is accompanied by a competing opinion. But recently scientists and scholars have challenged the legitimacy of this journalistic core value with regard to matters of great importance on which the overwhelming majority of the scientific community has reached a well-substantiated consensus view.

In a survey of 636 articles from four top United States newspapers between 1988 and 2002, two scholars found that most articles gave as much time to the small group of climate change doubters as to the scientific consensus view. Given real consensus among climatologists over global warming, many scientists find the media's desire to portray the topic as a scientific controversy to be a gross distortion. As Stephen Schneider put it:

"a mainstream, well-established consensus may be 'balanced' against the opposing views of a few extremists, and to the uninformed, each position seems equally credible."

Science journalism concerns itself with gathering and evaluating various types of relevant evidence and rigorously checking sources and facts. Boyce Rensberger, the director of the Massachusetts Institute of Technology (MIT) Knight Center for Science Journalism, said, "balanced coverage of science does not mean giving equal weight to both sides of an argument. It means apportioning weight according to the balance of evidence."

The claims of scientists also get distorted by the media by a tendency to seek out extreme views, which can result in portrayal of risks well beyond the claims actually being made by scientists. Journalists tend to overemphasize the most extreme outcomes from a range of possibilities reported in scientific articles. A study that tracked press reports about a climate change article in the journal Nature found that "results and conclusions of the study were widely misrepresented, especially in the news media, to make the consequences seem more catastrophic and the timescale shorter."

A 2020 study in PNAS found that newspapers tended to give greater coverage of press releases that opposed action on climate change than those that supported action. The study attributes it to false balance.

Research that was done by Todd Newman, Erik Nisbet, and Matthew Nisbet shows that people's partisan preference is an indicator as to which media outlet they will most likely consume. Most media outlets often align with a particular partisan ideology. This causes people to resort to selective exposure which influences views on world issues such as climate change beliefs.

Alarmism

Alarmism is using inflated language, including an urgent tone and imagery of doom. In a report produced for the Institute for Public Policy Research Gill Ereaut and Nat Segnit suggested that alarmist language is frequently used in relation to environmental matters by newspapers, popular magazines and in campaign literature put out by the government and environment groups. It is claimed that when applied to climate change, alarmist language can create a greater sense of urgency. It has been argued that using sensational and alarming techniques, often evoke "denial, paralysis, or apathy" rather than motivating individuals to action and do not motivate people to become engaged with the issue of climate change. In the context of climate refugees—the potential for climate change to displace people—it has been reported that "alarmist hyperbole" is frequently employed by private military contractors and think tanks.

The term alarmist has been used as a pejorative by critics of mainstream climate science to describe those that endorse the scientific consensus without necessarily being unreasonable. MIT meteorologist Kerry Emanuel wrote that labeling someone as an "alarmist" is "a particularly infantile smear considering what is at stake." He continued that using this "inflammatory terminology has a distinctly Orwellian flavor."

Some media reports have used alarmist tactics to challenge the science related to global warming by comparing it with a purported episode of global cooling. In the 1970s, global cooling, a claim with limited scientific support (even during the height of a media frenzy over global cooling, "the possibility of anthropogenic warming dominated the peer-reviewed literature") was widely reported in the press. Several media pieces have claimed that since the even-at-the-time-poorly-supported theory of global cooling was shown to be false, that the well-supported theory of global warming can also be dismissed. For example, an article in The Hindu by Kapista and Bashkirtsev wrote: "Who remembers today, they query, that in the 1970s, when global temperatures began to dip, many warned that we faced a new ice age? An editorial in The Time magazine on June 24, 1974, quoted concerned scientists as voicing alarm over the atmosphere 'growing gradually cooler for the past three decades', 'the unexpected persistence and thickness of pack ice in the waters around Iceland,' and other harbingers of an ice age that could prove 'catastrophic.' Man was blamed for global cooling as he is blamed today for global warming", and the Irish Independent published an article claiming that "The widespread alarm over global warming is only the latest scare about the environment to come our way since the 1960s. Let's go through some of them. Almost exactly 30 years ago the world was in another panic about climate change. However, it wasn't the thought of global warming that concerned us. It was the fear of its opposite, global cooling. The doom-sayers were wrong in the past and it's entirely possible they're wrong this time as well." Numerous other examples exist.

Media, politics, and public discourse

As McCombs et al.'s 1972 study of the political function of mass media showed, media coverage of an issue can "play an important part in shaping political reality". Research into media coverage of climate change has demonstrated the significant role of the media in determining climate policy formation. The media has considerable bearing on public opinion, and the way in which issues are reported, or framed, establishes a particular discourse.

Media-policy interface

The relationship between media and politics is reflexive. As Feindt & Oels state, "[media] discourse has material and power effects as well as being the effect of material practices and power relations". Public support of climate change research ultimately decides whether or not funding for the research is made available to scientists and institutions.

Media coverage in the United States during the Bush Administration often emphasized and exaggerated scientific uncertainty over climate change, reflecting the interests of the political elite. Hall et al. suggest that government and corporate officials enjoy privileged access to the media, allowing their line to become the 'primary definer' of an issue. Media sources and their institutions very often have political leanings which determine their reporting on climate change, mirroring the views of a particular party. However, media also has the capacity to challenge political norms and expose corrupt behaviour, as demonstrated in 2007 when The Guardian revealed that American Enterprise Institute received $10,000 from petrochemical giant Exxon Mobil to publish articles undermining the IPCC's 4th assessment report.

Ever-strengthening scientific consensus on climate change means that skepticism is becoming less prevalent in the media (although the email scandal in the build up to Copenhagen reinvigorated climate skepticism in the media).

Discourses of action

The polar bear has become a symbol for those attempting to generate support for addressing climate change

Commentators have argued that the climate change discourses constructed in the media have not been conducive to generating the political will for swift action. The polar bear has become a powerful discursive symbol in the fight against climate change. However, such images may create a perception of climate change impacts as geographically distant, and MacNaghten argues that climate change needs to be framed as an issue 'closer to home'. On the other hand, Beck suggests that a major benefit of global media is that it brings distant issues within our consciousness.

Furthermore, media coverage of climate change (particularly in tabloid journalism but also more generally), is concentrated around extreme weather events and projections of catastrophe, creating "a language of imminent terror" which some commentators argue has instilled policy-paralysis and inhibited response. Moser et al. suggest using solution-orientated frames will help inspire action to solve climate change. The predominance of catastrophe frames over solution frames may help explain the apparent value-action gap with climate change; the current discursive setting has generated concern over climate change but not inspired action.

Breaking the prevailing notions in society requires discourse that is traditionally appropriate and approachable to common people. For example, Bill McKibben, an environmental activist, provides one approach to inspiring action: a war-like mobilization, where climate change is the enemy. This approach could resonate with working Americans who normally find themselves occupied with other news headlines.

Compared to what experts know about traditional media's and tabloid journalism's impacts on the formation of public perceptions of climate change and willingness to act, there is comparatively little knowledge of the impacts of social media, including message platforms like Twitter, on public attitudes toward climate change.

In recent years, there has been an increase in the influence and role that social media plays in conveying opinions and knowledge through information sharing. There are several emerging studies that explore the connection between social media and the public's awareness of climate change. Anderson found that there is evidence that social media can raise awareness of climate change issues, but warns that it can also lead to opinion-dominated ideologies and reinforcement. Another study examined datasets from Twitter to assess the ideas and attitudes that users of the application held toward climate change. Williams et al. found that users tend to be active in groups that share the same opinions, often at the extremes of the spectrum, resulting in less polarized opinions between the groups. These studies show that social media can have both a negative and positive impact on the information sharing of issues related to climate change.

Youth awareness and activism

Published in the journal Childhood, the article "Children's protest in relation to the climate emergency: A qualitative study on a new form of resistance promoting political and social change" considers how children have evolved into prominent actors to create a global impact on awareness of climate change. It highlights the work of children like Greta Thunberg and the significance of their resistance to the passivity of world leaders regarding climate change. It also discusses how individual resistance can directly be linked to collective resistance and that this then creates a more powerful impact, empowering young people to act more responsibly and take authority over the future. The article discusses the potential impact of youth to raise awareness while also inspiring action, and using social media platforms to share the message.

Coverage by country

Results of a survey in 31 countries of public opinion on the causes of climate change in 2021.

Australia

See also: Climate change in Australia

Australian news outlets have been reported to present misleading claims and information. One article from The Australian in 2009 claimed that climate change and global warming were fraudulent claims pushed by so-called "warmaholics". Many other examples of claims that dismiss climate change have been posted by media outlets in Australia throughout the years following as well. The 2013 summer and heat wave colloquially known as "Angry Summer" attracted a great deal of media attention, although few outlets directly linked the unprecedented heat to climate change. As the world entered into 2020, global media coverage of climate change issues decreased and COVID-19 coverage increased. In Australia there was a 34% decrease in climate change articles published from March 2020. A 2022 analysis found that Sky News Australia was a major source of climate misinformation globally.

Australia has recently experienced some of the most intense bushfire seasons in its immediate history. This phenomenon has sparked extensive media coverage both nationally and internationally. Much of the media coverage of the 2019 and 2020 Australian bushfire seasons discussed the different factors that lead to and increase the chances of extreme fire seasons. A climate scientist, Nerilie Abram, at Australian National University explained in an article for Scientific American, that the four major conditions need to exist for wildfire and those include "available fuel, dryness of that fuel, weather conditions that aid the rapid spread of fire and an ignition.

Canada

Further information: Environmental policy of the Harper government § Media coverage of climate change

During the Harper government (2006-2015), Canadian media, mostly notably the CBC, made little effort to balance the claims of global warming deniers with voices from science. The Canadian coverage appeared to be driven more by national and international political events rather than the changes to carbon emissions or various other ecological factors. The discourse was dominated by matters of government responsibility, policy-making, policy measures for mitigation, and ways to mitigate climate change; with the issue coverage by mass media outlets continuing to act as an important means of communicating environmental concerns to the general public, rather than introducing new ideas about the topic itself.

Within various provincial and language media outlets, there are varying levels of articulation regarding scientific consensus and the focus on ecological dimensions of climate change. Within Quebec, specifically, these outlets are more likely to position climate change as an international issue, and to link climate change to social justice concerns in order to depict Quebec as a pro-environmental society.

Across various nations, including Canada, there has been an increased effort in the use of celebrities in climate change coverage, which is able to gain audience attention, but in turn, it reinforces individualized rather than structural interpretations of climate change responsibility and solutions.

China

See also: Climate change in China

Sweden

See also: Climate change in Sweden

Japan

See also: Climate change in Japan

In Japan, a study of newspaper coverage of climate change from January 1998 to July 2007 found coverage increased dramatically from January 2007.

India

See also: Climate change in India

A 2010 study of four major, national circulation English-language newspapers in India examined "the frames through which climate change is represented in India", and found that "The results strongly contrast with previous studies from developed countries; by framing climate change along a 'risk-responsibility divide', the Indian national press set up a strongly nationalistic position on climate change that divides the issue along both developmental and postcolonial lines."

On the other hand, a qualitative analysis of some mainstream Indian newspapers (particularly opinion and editorial pieces) during the release of the IPCC 4th Assessment Report and during the Nobel Peace Prize win by Al Gore and the IPCC found that Indian media strongly pursue scientific certainty in their coverage of climate change. This is in contrast to the skepticism displayed by American newspapers at the time. Indian media highlights energy challenges, social progress, public accountability and looming disaster.

Ireland

Ireland has quite a low coverage of climate change in media. A survey created shows how the Irish Times had only 0.84% of news coverage for climate change in the space of 13 years. This percentage is low compared to the rest of Europe. For example- Coverage of climate change in Ireland 10.6 stories, while the rest of Europe lies within 58.4 stories.

New Zealand

See also: Climate change in New Zealand

A six-month study in 1988 on climate change reporting in the media found that 80% of stories were no worse than slightly inaccurate. However, one story in six contained significant misreporting. Al Gore's film An Inconvenient Truth in conjunction with the Stern Review generated an increase in media interest in 2006.

The popular media in New Zealand often give equal weight to those supporting anthropogenic climate change and those who deny it. This stance is out of step with the findings of the scientific community where the vast majority support the climate change scenarios. A survey carried out in 2007 on climate change gave the following responses:

Not really a problem	8%
A problem for the future	13%
A problem now	42%
An urgent and immediate problem	35%
Don't know	2%

Turkey

See also: Greenhouse gas emissions by Turkey and Climate change in Turkey

According to journalist Pelin Cengiz mainstream media tends to cover newly opened coal-fired power stations in Turkey as increasing employment rather than climate change, and almost all owners have financial interests in fossil fuels.

United Kingdom

See also: Climate change in the United Kingdom § Media coverage

The Guardian newspaper is internationally respected for its coverage of climate change.

United States

See also: Climate change in the United States and Propaganda model § Applications

One of the first critical studies of media coverage of climate change in the United States appeared in 1999. The author summarized her research:

Following a review of the decisive role of the media in American politics and of a few earlier studies of media bias, this paper examines media coverage of the greenhouse effect. It does so by comparing two pictures. The first picture emerges from reading all 100 greenhouse-related articles published over a five-month period (May–September 1997) in The Christian Science Monitor, New York Times, The San Francisco Chronicle, and The Washington Post. The second picture emerges from the mainstream scientific literature. This comparison shows that media coverage of environmental issues suffers from both shallowness and pro-corporate bias.

According to Peter J. Jacques et al., the mainstream news media of the United States is an example of the effectiveness of environmental skepticism as a tactic. A 2005 study reviewed and analyzed the US mass-media coverage of the environmental issue of climate change from 1988 to 2004. The authors confirm that within the journalism industry there is great emphasis on eliminating the presence of media bias. In their study they found that — due to this practice of journalistic objectivity — "Over a 15-year period, a majority (52.7%) of prestige-press articles featured balanced accounts that gave 'roughly equal attention' to the views that humans were contributing to global warming and that exclusively natural fluctuations could explain the earth's temperature increase [...] US mass-media have misrepresented the top climate scientific perspective regarding anthropogenic climate change." As a result, they observed that it is unsurprising for the public to believe that the issue of global warming and the accompanying scientific evidence is still hotly debated.

A study of US newspapers and television news from 1995 to 2006 examined "how and why US media have represented conflict and contentions, despite an emergent consensus view regarding anthropogenic climate science." The IPCC Assessment Reports in 1995 and in 2001 established an increasingly strong scientific consensus, yet the media continued to present the science as contentious. The study noted the influence of Michael Crichton's 2004 novel State of Fear, which "empowered movements across scale, from individual perceptions to the perspectives of US federal powerbrokers regarding human contribution to climate change."

A 2010 study concluded that "Mass media in the U.S. continue to suggest that scientific consensus estimates of global climate disruption, such as those from the Intergovernmental Panel on Climate Change (IPCC), are 'exaggerated' and overly pessimistic. By contrast, work on the Asymmetry of Scientific Challenge (ASC) suggests that such consensus assessments are likely to understate climate disruptions [...] new scientific findings were more than twenty times as likely to support the ASC perspective than the usual framing of the issue in the U.S. mass media. The findings indicate that supposed challenges to the scientific consensus on global warming need to be subjected to greater scrutiny, as well as showing that, if reporters wish to discuss "both sides" of the climate issue, the scientifically legitimate 'other side' is that, if anything, global climate disruption may prove to be significantly worse than has been suggested in scientific consensus estimates to date."

Scientific consensus on climate change (left) versus attitudes of Fox News guests in 2013 (right)

The most watched news network in the United States, Fox News, most of the time promotes climate misinformation and employs tactics that distract from the urgency of global climate change, according to a 2019 study by Public Citizen. According to the study, 86% of Fox News segments that discussed the topic were "dismissive of the climate crisis, cast its consequences in doubt or employed fear mongering when discussing climate solutions." These segments presented global climate change as a political construct, rarely, if ever, discussing the threat posed by climate change or the vast body of scientific evidence for its existence. Consistent with such politicized framing, three messages were most commonly advanced in these segments: global climate change is part of a "big government" agenda of the Democratic Party (34% of segments); an effective response to the climate crisis would destroy the economy and hurtle us back to the Stone Age (26% of segments); and, concern about the climate crisis is "alarmists", "hysterical," the shrill voice of a "doomsday climate cult," or the like (12% of segments). Such segments often featured "experts" who are not climate scientists at all or are personally connected to vested interests, such as the energy industry and its network of lobbyists and think tanks, for example, the Heartland Institute, funded by the Exxon Mobil company and the Koch foundation. The remaining segments (14%) were neutral on the subject or presented information without editorializing.

It has been suggested that the association of climate change with the Arctic in popular media may undermine effective communication of the scientific realities of anthropogenic climate change. The close association of images of Arctic glaciers, ice, and fauna with climate change might harbor cultural connotations that contradict the fragility of the region. For example, in cultural-historical narratives, the Arctic was depicted as an unconquerable, foreboding environment for explorers; in climate change discourse, the same environment is sought to be understood as fragile and easily affected by humanity.

Gallup's annual update on Americans' attitudes toward the environment shows a public that over the last two years (2008-2010) has become less worried about the threat of global warming, less convinced that its effects are already happening, and more likely to believe that scientist themselves are uncertain about its occurrence. In response to one key question, 48% of Americans now believe that the seriousness of global warming is generally exaggerated, up from 41% in 2009 and 31% in 1997, when Gallup first asked the question.

Data from the Media Matters for America organization has shown that, despite 2015 being "a year marked by more landmark actions to address climate change than ever before," the combined climate coverage on the top broadcast networks was down by 5% from 2014.

President Donald Trump denies the threat of global warming publicly. As a result of the Trump Presidency, media coverage on climate change was expected to decline during his term as president.

Globally, media coverage of global warming and climate change decreased in 2020. In the United States, however, newspaper coverage of climate change increased 29% between March 2020 and April 2020, these numbers are still 22% down from coverage in January 2020. This spike in April 2020 can be attributed to the increased coverage of the "Covering Climate Now'' campaign and the US holiday of "Earth Day". The overall decline in climate change coverage in the year 2020 is related to the increased coverage and interconnectedness of COVID-19 and President Trump, without mention of climate change, that began in January 2020.

The U.S. experienced its highest level of climate change media coverage to date in September and October 2021. This increase can be attributed to coverage of the United Nations Conference of Parties meeting which aimed to outline policies to address climate change.

Critical thinking

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Critical_thinking 

Critical thinking is the analysis of available facts, evidence, observations, and arguments in order to form a judgment by the application of rational, skeptical, and unbiased analyses and evaluation. The application of critical thinking include self-directed, self-disciplined, self-monitored, and self-corrective habits of mind, thus, a critical thinker is a person who practices the skills of critical thinking or has been trained and educated in its disciplines. Richard W. Paul said that the mind of a critical thinker engages the person's intellectual abilities and personality traits. Critical thinking presupposes assent to rigorous standards of excellence and mindful command of their use in effective communication and problem-solving, and a commitment to overcome egocentrism and sociocentrism.

History

Sculpture of Socrates

The earliest records of critical thinking are the teachings of Socrates, according to Plato. These included a part in Plato's early dialogues, where Socrates engages with one or more interlocutors on the issue of ethics such as to question whether it was right for Socrates to escape from prison. The philosopher considered and reflected on this question and came to the conclusion that escape violates all the things that he holds higher than himself: the laws of Athens and the guiding voice that Socrates claims to hear.

Socrates established the fact that one cannot depend upon those in "authority" to have sound knowledge and insight. He demonstrated that persons may have power and high position and yet be deeply confused and irrational. Socrates maintained that for an individual to have a good life or to have one that is worth living, he must be a critical questioner and possess an interrogative soul. He established the importance of asking deep questions that probe profoundly into thinking before we accept ideas as worthy of belief.

Socrates established the importance of "seeking evidence, closely examining reasoning and assumptions, analyzing basic concepts, and tracing out implications not only of what is said but of what is done as well". His method of questioning is now known as "Socratic questioning" and is the best known critical thinking teaching strategy. In his mode of questioning, Socrates highlighted the need for thinking for clarity and logical consistency. He asked people questions to reveal their irrational thinking or lack of reliable knowledge. Socrates demonstrated that having authority does not ensure accurate knowledge. He established the method of questioning beliefs, closely inspecting assumptions and relying on evidence and sound rationale. Plato recorded Socrates' teachings and carried on the tradition of critical thinking. Aristotle and subsequent Greek skeptics refined Socrates' teachings, using systematic thinking and asking questions to ascertain the true nature of reality beyond the way things appear from a glance.

Socrates set the agenda for the tradition of critical thinking, namely, to reflectively question common beliefs and explanations, carefully distinguishing beliefs that are reasonable and logical from those that—however appealing to our native egocentrism, however much they serve our vested interests, however comfortable or comforting they may be—lack adequate evidence or rational foundation to warrant belief.

Critical thinking was described by Richard W. Paul as a movement in two waves (1994). The "first wave" of critical thinking is often referred to as a 'critical analysis' that is clear, rational thinking involving critique. Its details vary amongst those who define it. According to Barry K. Beyer (1995), critical thinking means making clear, reasoned judgments. During the process of critical thinking, ideas should be reasoned, well thought out, and judged. The U.S. National Council for Excellence in Critical Thinking defines critical thinking as the "intellectually disciplined process of actively and skillfully conceptualizing, applying, analyzing, synthesizing, or evaluating information gathered from, or generated by, observation, experience, reflection, reasoning, or communication, as a guide to belief and action."

Etymology and origin of critical thinking

In the term critical thinking, the word critical, (Grk. κριτικός = kritikos = "critic") derives from the word critic and implies a critique; it identifies the intellectual capacity and the means "of judging", "of judgement", "for judging", and of being "able to discern". The intellectual roots of critical thinking are as ancient as its etymology, traceable, ultimately, to the teaching practice and vision of Socrates 2,500 years ago who discovered by a method of probing questioning that people could not rationally justify their confident claims to knowledge.

Definitions

Traditionally, critical thinking has been variously defined as follows:

• "The intellectually disciplined process of actively and skillfully conceptualizing, applying, analyzing, synthesizing, and/or evaluating information gathered from, or generated by, observation, experience, reflection, reasoning, or communication, as a guide to belief and action."
• "Disciplined thinking that is clear, rational, open-minded, and informed by evidence"
• "Purposeful, self-regulatory judgment which results in interpretation, analysis, evaluation, and inference, as well as explanation of the evidential, conceptual, methodological, criteriological, or contextual considerations upon which that judgment is based"
• "Includes a commitment to using reason in the formulation of our beliefs"
• The skill and propensity to engage in an activity with reflective scepticism (McPeck, 1981)
• Thinking about one's thinking in a manner designed to organize and clarify, raise the efficiency of, and recognize errors and biases in one's own thinking. Critical thinking is not 'hard' thinking nor is it directed at solving problems (other than 'improving' one's own thinking). Critical thinking is inward-directed with the intent of maximizing the rationality of the thinker. One does not use critical thinking to solve problems—one uses critical thinking to improve one's process of thinking.
• "An appraisal based on careful analytical evaluation"
• "Critical thinking is a type of thinking pattern that requires people to be reflective, and pay attention to decision-making which guides their beliefs and actions. Critical thinking allows people to deduct with more logic, to process sophisticated information and look at various sides of an issue so they can produce more solid conclusions."
• Critical thinking has seven critical features: being inquisitive and curious, being open-minded to different sides, being able to think systematically, being analytical, being persistent to truth, being confident about critical thinking itself, and lastly, being mature.
• Although critical thinking could be defined in several different ways, there is a general agreement in its key component—the desire to reach for a satisfactory result, and this should be achieved by rational thinking and result-driven manner. Halpern thinks that critical thinking firstly involves learned abilities such as problem-solving, calculation and successful probability application. It also includes a tendency to engage the thinking process. In recent times, Stanovich believed that modern IQ testing could hardly measure the ability of critical thinking.
• "Critical thinking is essentially a questioning, challenging approach to knowledge and perceived wisdom. It involves ideas and information from an objective position and then questioning this information in the light of our own values, attitudes and personal philosophy."

Contemporary critical thinking scholars have expanded these traditional definitions to include qualities, concepts, and processes such as creativity, imagination, discovery, reflection, empathy, connecting knowing, feminist theory, subjectivity, ambiguity, and inconclusiveness. Some definitions of critical thinking exclude these subjective practices.

1. According to Ennis, "Critical thinking is the intellectually disciplined process of actively and skillfully conceptualizing, applying, analyzing, synthesizing, and/or evaluating information gathered from, or generated by, observation, experience, reflection, reasoning, or communication, as a guide to belief and action." This definition Ennis provided is highly agreed by Harvey Siegel, Peter Facione, and Deanna Kuhn.
2. According to Ennis' definition, critical thinking requires a lot of attention and brain function. When a critical thinking approach is applied to education, it helps the student's brain function better and understand texts differently.
3. Different fields of study may require different types of critical thinking. Critical thinking provides more angles and perspectives upon the same material.

Logic and rationality

Main article: Logic and rationality

The study of logical argumentation is relevant to the study of critical thinking. Logic is concerned with the analysis of arguments, including the appraisal of their correctness or incorrectness. In the field of epistemology, critical thinking is considered to be logically correct thinking, which allows for differentiation between logically true and logically false statements.

In "First wave" logical thinking, the thinker is removed from the train of thought, and the analysis of connections between concepts or points in thought is ostensibly free of any bias. In his essay Beyond Logicism in Critical Thinking Kerry S. Walters describes this ideology thus: "A logistic approach to critical thinking conveys the message to students that thinking is legitimate only when it conforms to the procedures of informal (and, to a lesser extent, formal) logic and that the good thinker necessarily aims for styles of examination and appraisal that are analytical, abstract, universal, and objective. This model of thinking has become so entrenched in conventional academic wisdom that many educators accept it as canon". Such principles are concomitant with the increasing dependence on a quantitative understanding of the world.

In the 'second wave' of critical thinking, authors consciously moved away from the logocentric mode of critical thinking characteristic of the 'first wave'. Although many scholars began to take a less exclusive view of what constitutes critical thinking, rationality and logic remain widely accepted as essential bases for critical thinking. Walters argues that exclusive logicism in the first wave sense is based on "the unwarranted assumption that good thinking is reducible to logical thinking".

Deduction, abduction and induction

Argument terminology used in logic

 

Main article: logical reasoning

There are three types of logical reasoning. Informally, two kinds of logical reasoning can be distinguished in addition to formal deduction, which are induction and abduction.

Deduction

• Deduction is the conclusion drawn from the structure of an argument's premises, by use of rules of inference formally those of propositional calculus. For example: X is human and all humans have a face, so X has a face.

Induction

• Induction is drawing a conclusion from a pattern that is guaranteed by the strictness of the structure to which it applies. For example: The sum of even integers is even. Let ${\displaystyle x,y,z\in \mathbb{Z}}$ then ${\displaystyle 2x,2y,2z}$ are even by definition. ${\displaystyle 2x+2y=2(x+y)=2z}$, which is even; so summing two even numbers results in an even number.

Abduction

• Abduction is drawing a conclusion using a heuristic that is likely, but not inevitable given some foreknowledge. For example: I observe sheep in a field, and they appear white from my viewing angle, so sheep are white. Contrast with the deductive statement: Some sheep are white on at least one side.

Critical thinking and rationality

Kerry S. Walters, an emeritus philosophy professor from Gettysburg College, argues that rationality demands more than just logical or traditional methods of problem solving and analysis or what he calls the "calculus of justification" but also considers "cognitive acts such as imagination, conceptual creativity, intuition and insight". These "functions" are focused on discovery, on more abstract processes instead of linear, rules-based approaches to problem-solving. The linear and non-sequential mind must both be engaged in the rational mind.

The ability to critically analyze an argument—to dissect structure and components, thesis and reasons—is essential. But so is the ability to be flexible and consider non-traditional alternatives and perspectives. These complementary functions are what allow for critical thinking to be a practice encompassing imagination and intuition in cooperation with traditional modes of deductive inquiry.

Functions

The list of core critical thinking skills includes observation, interpretation, analysis, inference, evaluation, explanation, and metacognition. According to Reynolds (2011), an individual or group engaged in a strong way of critical thinking gives due consideration to establish for instance:

• Evidence through reality
• Context skills to isolate the problem from context
• Relevant criteria for making the judgment well
• Applicable methods or techniques for forming the judgment
• Applicable theoretical constructs for understanding the problem and the question at hand

In addition to possessing strong critical-thinking skills, one must be disposed to engage problems and decisions using those skills. Critical thinking employs not only logic but broad intellectual criteria such as clarity, credibility, accuracy, precision, relevance, depth, breadth, significance, and fairness.

Critical thinking calls for the ability to:

• Recognize problems, to find workable means for meeting those problems
• Understand the importance of prioritization and order of precedence in problem-solving
• Gather and marshal pertinent (relevant) information
• Recognize unstated assumptions and values
• Comprehend and use language with accuracy, clarity, and discernment
• Interpret data, to appraise evidence and evaluate arguments
• Recognize the existence (or non-existence) of logical relationships between propositions
• Draw warranted conclusions and generalizations
• Put to test the conclusions and generalizations at which one arrives
• Reconstruct one's patterns of beliefs on the basis of wider experience
• Render accurate judgments about specific things and qualities in everyday life

In sum:

"A persistent effort to examine any belief or supposed form of knowledge in the light of the evidence that supports or refutes it and the further conclusions to which it tends."

Habits or traits of the mind

The habits of mind that characterize a person strongly disposed toward critical thinking include a desire to follow reason and evidence wherever they may lead, a systematic approach to problem solving, inquisitiveness, even-handedness, and confidence in reasoning.

According to a definition analysis by Kompf & Bond (2001), critical thinking involves problem solving, decision making, metacognition, rationality, rational thinking, reasoning, knowledge, intelligence and also a moral component such as reflective thinking. Critical thinkers therefore need to have reached a level of maturity in their development, possess a certain attitude as well as a set of taught skills.

There is a postulation by some writers that the tendencies from habits of mind should be thought as virtues to demonstrate the characteristics of a critical thinker. These intellectual virtues are ethical qualities that encourage motivation to think in particular ways towards specific circumstances. However, these virtues have also been criticized by skeptics who argue that the evidence is lacking for a specific mental basis underpinning critical thinking.

Research in critical thinking

After undertaking research in schools, Edward M. Glaser proposed in 1941 that the ability to think critically involves three elements:

1. An attitude of being disposed to consider in a thoughtful way the problems and subjects that come within the range of one's experiences
2. Knowledge of the methods of logical inquiry and reasoning
3. Some skill in applying those methods.

Educational programs aimed at developing critical thinking in children and adult learners, individually or in group problem solving and decision making contexts, continue to address these same three central elements.

The Critical Thinking project at Human Science Lab, London, is involved in the scientific study of all major educational systems in prevalence today to assess how the systems are working to promote or impede critical thinking.

Contemporary cognitive psychology regards human reasoning as a complex process that is both reactive and reflective. This presents a problem which is detailed as a division of a critical mind in juxtaposition to sensory data and memory.

The psychological theory disposes of the absolute nature of the rational mind, in reference to conditions, abstract problems and discursive limitations. Where the relationship between critical thinking skills and critical thinking dispositions is an empirical question, the ability to attain causal domination exists, for which Socrates was known to be largely disposed against as the practice of Sophistry. Accounting for a measure of "critical thinking dispositions" is the California Measure of Mental Motivation and the California Critical Thinking Dispositions Inventory. The Critical Thinking Toolkit is an alternative measure that examines student beliefs and attitudes about critical thinking.

Education

John Dewey is one of many educational leaders who recognized that a curriculum aimed at building thinking skills would benefit the individual learner, the community, and the entire democracy.

Critical thinking is significant in the learning process of internalization, in the construction of basic ideas, principles, and theories inherent in content. And critical thinking is significant in the learning process of application, whereby those ideas, principles, and theories are implemented effectively as they become relevant in learners' lives.

Each discipline adapts its use of critical thinking concepts and principles. The core concepts are always there, but they are embedded in subject-specific content. For students to learn content, intellectual engagement is crucial. All students must do their own thinking, their own construction of knowledge. Good teachers recognize this and therefore focus on the questions, readings, activities that stimulate the mind to take ownership of key concepts and principles underlying the subject.

Historically, the teaching of critical thinking focused only on logical procedures such as formal and informal logic. This emphasized to students that good thinking is equivalent to logical thinking. However, a second wave of critical thinking, urges educators to value conventional techniques, meanwhile expanding what it means to be a critical thinker. In 1994, Kerry Walters compiled a conglomeration of sources surpassing this logical restriction to include many different authors' research regarding connected knowing, empathy, gender-sensitive ideals, collaboration, world views, intellectual autonomy, morality and enlightenment. These concepts invite students to incorporate their own perspectives and experiences into their thinking.

In the English and Welsh school systems, Critical Thinking is offered as a subject that 16- to 18-year-olds can take as an A-Level. Under the OCR exam board, students can sit two exam papers for the AS: "Credibility of Evidence" and "Assessing and Developing Argument". The full Advanced GCE is now available: in addition to the two AS units, candidates sit the two papers "Resolution of Dilemmas" and "Critical Reasoning". The A-level tests candidates on their ability to think critically about, and analyze, arguments on their deductive or inductive validity, as well as producing their own arguments. It also tests their ability to analyze certain related topics such as credibility and ethical decision-making. However, due to its comparative lack of subject content, many universities do not accept it as a main A-level for admissions. Nevertheless, the AS is often useful in developing reasoning skills, and the full Advanced GCE is useful for degree courses in politics, philosophy, history or theology, providing the skills required for critical analysis that are useful, for example, in biblical study.

There used to also be an Advanced Extension Award offered in Critical Thinking in the UK, open to any A-level student regardless of whether they have the Critical Thinking A-level. Cambridge International Examinations have an A-level in Thinking Skills.

From 2008, Assessment and Qualifications Alliance has also been offering an A-level Critical Thinking specification. OCR exam board have also modified theirs for 2008. Many examinations for university entrance set by universities, on top of A-level examinations, also include a critical thinking component, such as the LNAT, the UKCAT, the BioMedical Admissions Test and the Thinking Skills Assessment.

In Qatar, critical thinking was offered by Al-Bairaq - an outreach, non-traditional educational program that targeted high school students and focussed on a curriculum based on STEM fields. The idea behind this was to offer high school students the opportunity to connect with the research environment in the Center for Advanced Materials (CAM) at Qatar University. Faculty members train and mentor the students and help develop and enhance their critical thinking, problem-solving, and teamwork skills.

Effectiveness

In 1995, a meta-analysis of the literature on teaching effectiveness in higher education was undertaken. The study noted concerns from higher education, politicians, and business that higher education was failing to meet society's requirements for well-educated citizens. It concluded that although faculty may aspire to develop students' thinking skills, in practice they have tended to aim at facts and concepts utilizing lowest levels of cognition, rather than developing intellect or values.

In a more recent meta-analysis, researchers reviewed 341 quasi- or true-experimental studies, all of which used some form of standardized critical thinking measure to assess the outcome variable. The authors describe the various methodological approaches and attempt to categorize the differing assessment tools, which include standardized tests (and second-source measures), tests developed by teachers, tests developed by researchers, and tests developed by teachers who also serve the role as the researcher. The results emphasized the need for exposing students to real-world problems and the importance of encouraging open dialogue within a supportive environment. Effective strategies for teaching critical thinking are thought to be possible in a wide variety of educational settings. One attempt to assess the humanities' role in teaching critical thinking and reducing belief in pseudoscientific claims was made at North Carolina State University. Some success was noted and the researchers emphasized the value of the humanities in providing the skills to evaluate current events and qualitative data in context.

Scott Lilienfeld notes that there is some evidence to suggest that basic critical thinking skills might be successfully taught to children at a younger age than previously thought.

Importance in academics

Critical thinking is an important element of all professional fields and academic disciplines (by referencing their respective sets of permissible questions, evidence sources, criteria, etc.). Within the framework of scientific skepticism, the process of critical thinking involves the careful acquisition and interpretation of information and use of it to reach a well-justified conclusion. The concepts and principles of critical thinking can be applied to any context or case but only by reflecting upon the nature of that application. Critical thinking forms, therefore, a system of related, and overlapping, modes of thought such as anthropological thinking, sociological thinking, historical thinking, political thinking, psychological thinking, philosophical thinking, mathematical thinking, chemical thinking, biological thinking, ecological thinking, legal thinking, ethical thinking, musical thinking, thinking like a painter, sculptor, engineer, business person, etc. In other words, though critical thinking principles are universal, their application to disciplines requires a process of reflective contextualization. Psychology offerings, for example, have included courses such as Critical Thinking about the Paranormal, in which students are subjected to a series of cold readings and tested on their belief of the "psychic", who is eventually announced to be a fake.

Critical thinking is considered important in the academic fields for enabling one to analyze, evaluate, explain, and restructure thinking, thereby ensuring the act of thinking without false belief. However, even with knowledge of the methods of logical inquiry and reasoning, mistakes occur, and due to a thinker's inability to apply the methodology consistently, and because of overruling character traits such as egocentrism. Critical thinking includes identification of prejudice, bias, propaganda, self-deception, distortion, misinformation, etc. Given research in cognitive psychology, some educators believe that schools should focus on teaching their students critical thinking skills and cultivation of intellectual traits.

Critical thinking skills can be used to help nurses during the assessment process. Through the use of critical thinking, nurses can question, evaluate, and reconstruct the nursing care process by challenging the established theory and practice. Critical thinking skills can help nurses problem solve, reflect, and make a conclusive decision about the current situation they face. Critical thinking creates "new possibilities for the development of the nursing knowledge". Due to the sociocultural, environmental, and political issues that are affecting healthcare delivery, it would be helpful to embody new techniques in nursing. Nurses can also engage their critical thinking skills through the Socratic method of dialogue and reflection. This practice standard is even part of some regulatory organizations such as the College of Nurses of Ontario's Professional Standards for Continuing Competencies (2006). It requires nurses to engage in Reflective Practice and keep records of this continued professional development for possible review by the college.

Critical thinking is also considered important for human rights education for toleration. The Declaration of Principles on Tolerance adopted by UNESCO in 1995 affirms that "education for tolerance could aim at countering factors that lead to fear and exclusion of others, and could help young people to develop capacities for independent judgement, critical thinking and ethical reasoning".

Online communication

The advent and rising popularity of online courses have prompted some to ask if computer-mediated communication (CMC) promotes, hinders, or has no effect on the amount and quality of critical thinking in a course (relative to face-to-face communication). There is some evidence to suggest a fourth, more nuanced possibility: that CMC may promote some aspects of critical thinking but hinder others. For example, Guiller et al. (2008) found that, relative to face-to-face discourse, online discourse featured more justifications, while face-to-face discourse featured more instances of students expanding on what others had said. The increase in justifications may be due to the asynchronous nature of online discussions, while the increase in expanding comments may be due to the spontaneity of 'real-time' discussion. Newman et al. (1995) showed similar differential effects. They found that while CMC boasted more important statements and linking of ideas, it lacked novelty. The authors suggest that this may be due to difficulties participating in a brainstorming-style activity in an asynchronous environment. Rather, the asynchrony may promote users to put forth "considered, thought out contributions".

Researchers assessing critical thinking in online discussion forums often employ a technique called Content Analysis, where the text of online discourse (or the transcription of face-to-face discourse) is systematically coded for different kinds of statements relating to critical thinking. For example, a statement might be coded as "Discuss ambiguities to clear them up" or "Welcoming outside knowledge" as positive indicators of critical thinking. Conversely, statements reflecting poor critical thinking may be labeled as "Sticking to prejudice or assumptions" or "Squashing attempts to bring in outside knowledge". The frequency of these codes in CMC and face-to-face discourse can be compared to draw conclusions about the quality of critical thinking.

Searching for evidence of critical thinking in discourse has roots in a definition of critical thinking put forth by Kuhn (1991), which emphasizes the social nature of discussion and knowledge construction. There is limited research on the role of social experience in critical thinking development, but there is some evidence to suggest it is an important factor. For example, research has shown that 3- to 4-year-old children can discern, to some extent, the differential creditability and expertise of individuals. Further evidence for the impact of social experience on the development of critical thinking skills comes from work that found that 6- to 7-year-olds from China have similar levels of skepticism to 10- and 11-year-olds in the United States. If the development of critical thinking skills was solely due to maturation, it is unlikely we would see such dramatic differences across cultures.

Deglaciation

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Deglaciation 

Deglaciation is the transition from full glacial conditions during ice ages, to warm interglacials, characterized by global warming and sea level rise due to change in continental ice volume. Thus, it refers to the retreat of a glacier, an ice sheet or frozen surface layer, and the resulting exposure of the Earth's surface. The decline of the cryosphere due to ablation can occur on any scale from global to localized to a particular glacier. After the Last Glacial Maximum (ca. 21,000 years ago), the last deglaciation begun, which lasted until the early Holocene. Around much of Earth, deglaciation during the last 100 years has been accelerating as a result of climate change, partly brought on by anthropogenic changes to greenhouse gases. 

The previous deglaciation took place from approximately 22 ka until 11.5 ka. This occurred when there was an annual mean atmospheric temperature on the earth that increased by roughly 5 °C, which was also accompanied by regional high-latitude warming that exceeded 10 °C. This was also followed by noteworthy deep-sea and tropical-sea warming, of about 1–2 °C (deep-sea) and 2–4 °C (tropical sea). Not only did this warming occur, but the global hydrological budget also experienced noticeable changes and regional precipitation patterns changed. As a result of all of this, the world's main ice sheets, including the ones located in Eurasia, North America and parts of the Antarctic melted. As a consequence, sea levels rose roughly 120 metres. These processes did not occur steadily, and they also did not occur at the same time.

Background

The process of deglaciation reflects a lack of balance between existing glacial extent and climatic conditions. As a result of net negative mass balance over time, glaciers and ice sheets retreat. The repeated periods of increased and decreased extent of the global cryosphere (as deduced from observations of ice and rock cores, surface landforms, sub-surface geologic structures, the fossil record, and other methods of dating) reflect the cyclical nature of global and regional glaciology measured by ice ages and smaller periods known as glacials and interglacials. Since the end of the Last glacial period about 12,000 years ago, ice sheets have retreated on a global scale, and Earth has been experiencing a relatively warm interglacial period marked by only high-altitude alpine glaciers at most latitudes with larger ice sheet and sea ice at the poles. However, since the onset of the Industrial Revolution, human activity has contributed to a rapid increase in the speed and scope of deglaciation globally.

Greenland

Research published in 2014 suggests that below Greenland's Russell Glacier's ice sheet, methanotrophs could serve as a biological methane sink for the subglacial ecosystem, and the region was at least during the sample time, a source of atmospheric methane. Based on dissolved methane in water samples, Greenland may represent a significant global methane source, and may contribute significantly more due to ongoing deglaciation. A study in 2016 concluded based on past evidence, that below Greenland's and Antarctica's ice sheet may exist methane clathrates.

Causes and effects

See also: Sea level rise

At every scale, climate influences the condition of snow and ice on Earth's surface. In colder periods massive ice sheets may extend toward the Equator, while in periods warmer than today, the Earth may be completely free of ice. A significant, empirically demonstrated, positive relationship exists between the surface temperature and concentration of Greenhouse gases such as CO₂ in the atmosphere. The higher concentration, in turn, has a drastic negative impact on the global extent and stability of the cryosphere. On the millennial time scales of Pleistocene glacial and interglacial cycles, the pacemaker of glaciation onset and melting are changes in orbital parameters termed the Milankovitch cycles. Specifically, low summer insolation in the northern hemisphere permits growth of ice sheets, while high summer insolation causes more ablation than winter snow accumulation.

Human activities promoting climate change, notably the extensive use of fossil fuels over the last 150 years and the resulting increase in atmospheric CO₂ concentrations, are the principal cause of the more rapid retreat of alpine glaciers and continental ice sheets all across the world. For example, the West Antarctic Ice Sheet has receded significantly, and is now contributing to a positive feedback loop that threatens further deglaciation or collapse. Newly exposed areas of the Southern Ocean contain long-sequestered stores of CO₂ which are now being emitted into the atmosphere and are continuing to impact glacial dynamics.

The principle of isostasy applies directly to the process of deglaciation, especially post-glacial rebound, which is one of main mechanisms through which isostasy is observed and studied. Post-glacial rebound refers to the increase in tectonic uplift activity immediately following glacial retreat. Increased rates and abundance of volcanic activity have been found in regions experiencing post-glacial rebound. If on a large enough scale, an increase in volcanic activity provides a positive feedback to the process of deglaciation as a result CO₂ and methane released from volcanos.

Periods of deglaciation are also caused in part by oceanic processes. For example, interruptions of the usual deep cold water circulation and penetration depths in the North Atlantic have feedbacks that promote further glacial retreat.

Deglaciation influences sea level because water previously held on land in solid form turns into liquid water and eventually drains into the ocean. The recent period of intense deglaciation has resulted in an average global sea level rise of 1.7 mm/year for the entire 20th century, and 3.2 mm/year over the past two decades, a very rapid increase.

The physical mechanisms by which deglaciation occurs include melting, evaporation, sublimation, calving, and aeolian processes such as wind scouring.

Deglaciation of the Laurentide Ice Sheet

Throughout the Pleistocene Epoch, the Laurentide Ice Sheet spread over large areas of northern North America, with over 5,000,000 square miles of coverage. The Laurentide ice sheet was 10,000 feet deep in some areas, and reached as far south as 37°N. Mapped extent of the Laurentide Ice Sheet during deglaciation has been prepared by Dyke et al. Cycles of deglaciation are driven by various factors, with the main driver being changes in incoming summer solar radiation, or insolation, in the Northern Hemisphere. But, as not all of the rises in insolation throughout time caused deglaciation, to the current ice volumes that we witness today. This leads to a different conclusion, one that suggests that there is a possible climatic threshold, in terms of ice sheets retreating, and eventually disappearing. As Laurentide was the largest mass ice sheet in the Northern Hemisphere, much study has been conducted regarding its disappearance, unloading energy balance models, atmosphere-ocean general circulation models, and surface energy balance models. These studies concluded that the Laurentide ice sheet presented a positive surface mass balance during almost the entirety of its deglaciation, which indicates that the loss of mass throughout its deglaciation was more than likely due to dynamic discharge. It was not until the early Holocene when the surface mass balance switched to become negative. This change to a negative surface mass balance suggested that surface ablation became the driver that resulted in the loss of mass of ice in the Laurentide ice sheet. It is concluded then that the Laurentide ice sheet only began to exhibit behaviours and patterns of deglaciation after radiative forcing and summer temperatures began to rise at the beginning of the Holocene.

Result of the deglaciation of the Laurentide ice sheet

When the Laurentide ice sheet progressed through the process of deglaciation, it created many new landforms and had various effects of the land. First and foremost, as huge glaciers melt, there is a consequently large volume of meltwater. The volumes of meltwater created many features, including proglacial freshwater lakes, which can be sizable. Not only was there meltwater that formed lakes, there were also storms that blew over the inland freshwater. These storms created waves strong enough to erode the ice shores. Once ice cliffs were exposed, due to rising sea levels and erosion caused by waves, the ice bergs were split and shed (calved) off. Large lakes became prevalent, but so did smaller, shallower, relatively short-lived lakes. This appearance and disappearance of small, shallow lakes influenced much of the plant growth, spread and diversity that we see today. The lakes acted as barriers to plant migration, but when these lakes drained, the plants could migrate and spread very efficiently.

The last deglaciation

Main article: Holocene glacial retreat

 

Temperature from 20,000 to 10,000 years ago, derived from EPICA Dome C Ice Core (Antarctica)

 

The Post-Glacial Sea Level

The period between the end of the Last Glacial Maximum to the early Holocene (ca. 19k-11k years ago), shows changes in greenhouse gas concentrations and of the Atlantic meridional overturning circulation (AMOC), when sea-level rose by 80 meters. Additionally, the last deglaciation is marked by three abrupt CO₂ pulses, and records of volcanic eruptions show that subaerial volcanism increased globally by two to six times above background levels between 12 ka and 7 ka.

Between roughly 19ka, the end of the Last Glacial Maximum (or LGM) to 11ka, which was the early Holocene, the climate system experienced drastic transformation. Much of this change was occurring at an astonishing rate, as the earth was dealing with the end of the last ice age. Changes in insolation was the principal reason for this drastic global change in climate, as this was linked with several other changes globally, from the alteration of ice sheets, to the concentration of greenhouse gases fluctuating, and many other feedbacks that resulted in distinct responses, both globally and regionally. Not only were ice sheets and greenhouse gases experiencing alteration, but also additionally to this, there was sudden climate change, and many occurrences of fast, and sizeable rising of sea level. The melting of the ice sheets, along with the rising sea levels did not happen until after 11ka. Nonetheless, the globe had arrived at its present interglacial period, where climate is comparatively constant and stable, and greenhouse gas concentrations exhibit near pre-industrial levels. This data is all available due to studies and information gathered from proxy records, both from the terrestrial and ocean, which illustrates overall global patterns of changes in climate whilst in the period of Deglaciation. 

During the Last Glacial Maximum (LGM), there were apparent low atmospheric concentration of Carbon Dioxide (CO₂), which was believed to be as a result of larger containment of carbon in the deep ocean, via the process of stratification within the Southern Ocean. These Southern Ocean deep waters contained the least δ13C, which consequently resulted in them being the location with the greatest density, and most salt content during the LGM. The discharge of such sequestered carbon was perhaps a direct outcome of the deep Southern Ocean overturning, driven by heightened wind-driven upwelling, and sea-ice retreat, which are directly correlated to the warming of the Antarctic, and also coinciding with the cold events, the Oldest and Younger Dryas, in the north.

Throughout the LGM in North America, the east was populated by cold-tolerant conifer forests, while the southeast and northwest of the United States sustained open forests in locations that have closed forests today, which suggests that during the LGM temperatures were cooler and overall conditions were much drier than those that we experience today. There is also indication that the southwest of the United States was much wetter during the LGM compared to today, as there was open forest, where today we see desert and steppe. In the United States, the general variation of vegetation implies an overall fall in temperatures of (at minimum 5 °C), a shift of the westerly storm tracks to the south, and a very steep latitudinal temperature gradient. 

Landforms

Main article: Glacial landform

Several landforms visible today are distinctive of the powerful erosional forces at play during, or immediately after, deglaciation. The distribution of such landforms helps to inform the understanding of the glacial dynamics and geologic periods of the past. Studying exposed landforms can also inform the understanding of the present and near future as glaciers all over the world retreat in the current period of climate change. In general, recently deglacialized landscapes are inherently unstable and will tend to move towards an equilibrium.

A sampling of common landforms caused by deglaciation, or caused by the successive geomorphic processes after exposure due to deglaciation:

• Moraine
• Esker
• Kettle
• Kame
• Drumlin
• Thermokarst
• Tunnel valley
• Proglacial lake
• Subglacial channel