Special Report on Climate Change and Land

From Wikipedia, the free encyclopedia

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

 

Intergovernmental Panel on Climate Change

The United Nations' Intergovernmental Panel on Climate Change's (IPCC) Special Report on Climate Change and Land (SRCCL), also known as the "Special Report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems", is a landmark study from 2019 by 107 experts from 52 countries. The SRCCL provides a comprehensive overview of the entire land-climate system for the first time and decided to enlist land as a "critical resource". The IPCC's 50th session (IPCC-50) formally adopted the SRCCL's Summary for policymakers (SPM) and approved the underlying report. The SPM and the full text of Special Report on Climate Change and Land—in an unedited form—were released on 8 August 2019. The report is over 1,300 pages long and includes the work of 107 experts from 52 countries.

The report is the second of three Special Reports in the current Sixth Assessment Report (AR6) cycle which began in 2015 and will be completed in 2022. The first was Special Report on Global Warming of 1.5 °C, and the third is the Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC) released on 25 September 2019. The AR6 cycle is considered by the IPCC to be their most ambitious since the panel was formed in 1988.

Previous IPCC assessments cycles and special reports

Since it was established in 1988, the IPCC provides the governments of their 195 member countries, with periodic comprehensive summaries of scientific assessments of the drivers of climate change, including current impact and potential risks. The reports also put forward possible responses in terms of adaptation and mitigation. The IPCC has published five Assessment Reports, including the 1990 IPCC First Assessment Report (FAR), the 1995 IPCC Second Assessment Report also known as Climate Change 1995, the 2001 Third Assessment Report, the IPCC Fourth Assessment Report (AR4) also known as Climate Change 2007, and the Fifth Assessment Report. Each report also includes the "full scientific and technical assessment of climate change, generally in three volumes, one for each of the Working Groups of the IPCC, together with their Summaries for Policymakers, and a Synthesis Report."

SRCCL is part of a series of Special Reports and Assessments in the sixth assessment report (AR6) cycle which began in 2015—following the election of a new Bureau—and concludes in 2022. The IPCC considers the current assessment cycle to be their most ambitious in the 30-year history of the panel. So far, during this cycle, along with the SRCCL, IPCC has published the Special Report on Global Warming of 1.5 °C in October 2018, and the May 2019 Refinement. The third in the series, the Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC), is upcoming. As well, in March 2018, the IPCC held a conference Archived 2019-08-09 at the Wayback Machine in preparation for a special report on cities and climate change in the seventh assessment cycle.

Since its inception, the IPCC had also published over a dozen Special Reports which are included in the ARs. The Special report also includes a Summary for policymakers providing an "assessment of a specific issue and generally follow the same structure as a volume of an Assessment Report and Methodology Reports which are "materials that provide practical guidelines for the preparation of greenhouse gas inventories."

Sections

SRCCL summary for policymakers (SPM)

"Land provides the principal basis for human livelihoods and well-being including the supply of food, freshwater and multiple other ecosystem services, as well as biodiversity. Human use directly affects more than 70%...of the global, icefree land surface... Land also plays an important role in the climate system."

— SRCCL summary for policymakers (SPM)

There are four sections in the Summary for Policymakers (SPM). The first deals with "people, land and climate in a warming world"; the second covers "adaptation and mitigation response options"; the third focuses on "enabling response options" and the fourth considers "action in the near-term". In the first section, the SPM says that human-induced land degradation—with increased consumption and population growth causing more land use for "food, feed, fibre, timber and energy"—has negatively affected ice-free land area globally. Approximately "25–30% of total food produced is lost or wasted" while "821 million people are undernourished" and "2 billion adults now being overweight or obese." In part two, the SPM says that "increased food productivity, dietary choices and food losses and waste reduction, can reduce demand for land conversion." In part 3, suggested response options that will also help eradicate poverty, include "improving access to markets, securing land tenure, factoring environmental costs into food, making payments for ecosystem services, and enhancing local and community collective action". The SPM says that, "Many sustainable land management technologies and practices are profitable within three to 10 years (medium confidence). While they can require upfront investment, actions to ensure sustainable land management can improve crop yields and the economic value of pasture. Land restoration and rehabilitation measures improve livelihood systems and provide both short-term positive economic returns and longer-term benefits in terms of climate change adaptation and mitigation, biodiversity and enhanced ecosystem functions and services."

Chapters

The SRCCL consists of seven chapters, Chapter 1: Framing and Context, Chapter 2: Land-Climate Interactions, Chapter 3: Desertification, Chapter 4: Land Degradation, Chapter 5: Food Security, Chapter 5 Supplementary Material, Chapter 6: Interlinkages between desertification, land degradation, food security and GHG fluxes: Synergies, trade-offs and Integrated Response Options, and Chapter 7: Risk management and decision making in relation to sustainable development. Like all IPCC reports, the SRCCL includes a "Summary for Policymakers".

Chapter 1: Framing and context

..."Neither our individual or societal identities, nor the world's economy would exist without the multiple resources, services and livelihood systems provided by land ecosystems and biodiversity."

— Chapter 1

In the executive summary of Chapter 1, the authors described the land area on earth as "finite" saying that sustainable land use is "fundamental for human well-being."

One of the authors of "Framing and Context", Karlsruhe Institute of Technology's Almut Arneth, told Deutsche Presse-Agentur (DPA) journalists that "The surface of the earth is limited, the population is growing, and more acreage is needed for food and for fibres that can be used for clothing."

Chapter 2: Land-climate interactions

According to the 8 August Carbon Brief in-depth article on the SRCCL, Chapter 2 provides data on livestock methane emissions, about 66% is agricultural methane" and "about 33% of global methane emissions" come from livestock.

Chapter 3: Desertification

In Chapter 3, the authors said that while climate change is exacerbating desertification, there are technologies and innovations including those based on indigenous and local knowledge (ILK), that are available and that could, if put into practice in local regions, "avoid, reduce and reverse desertification, simultaneously contributing to climate change mitigation and adaptation."

Chapter 4: Land degradation

"Unravelling the impacts of climate-related land degradation on poverty and livelihoods is highly challenging. This complexity is due to the interplay of multiple social, political, cultural, and economic factors, such as markets, technology, inequality, population growth, each of which interact and shape the ways in which social-ecological systems respond."

— Chapter 4

While the impact of land degradation on peoples' livelihoods globally is already evident, "particularly those living in vulnerable and poverty-stricken regions", the authors of chapter four do not make a clear connection between climate change and land degradation because of the multiple factors at play which include inequality, population growth, technology, and markets.

Chapter 5: Food security

"The report highlights that climate change is affecting all four pillars of food security: availability (yield and production), access (prices and ability to obtain food), utilization (nutrition and cooking), and stability (disruptions to availability)."

— IPCC press release. 8 August 2019

Climate change has had a negative impact on vegetation at the same time that we are experiencing population growth. Ice-free land is needed to maintain food security. The IPCC report authors cautioned against "converting land" to bioenergy in which energy is produced by burning vegetation instead of burning fossil fuels, and advised countries to "set limits on the amount of land" used for energy crops—biofuels and afforestation. Land use in this way means there is less soil to grow much-needed food crops. In the original draft of the summary for policymakers the warning was even more pronounced, but it was considerably watered down due to the intervention of a group of governments led by Brazil, United States, United Kingdom and Sweden.

According to Chapter 5, with extreme weather events, rising temperatures increase, and either not enough or too much rain, there is more food insecurity. In some cases, yields of maize and wheat, for example, have increased in higher altitudes while yields of the same crops have declined in regions with lower altitudes. They also discuss "climate change-induced displacement and migration" in "eight countries in Asia, Africa and Latin America." They said that in countries such as, Guatemala, Honduras, and Nicaragua where 30% of the agriculture is dependent on rainfall, food security is undermined. They cited studies that show that migration from Mexico and Central America, fluctuates in "response to climate variability". Furthermore, in these countries, the "food system is heavily dependent on maize and bean production and long-term climate change and variability significantly affect the productivity of these crops and the livelihoods of smallholder farmers."

Chapter 6: Interlinkages

"IPCC does not recommend people's diets. What we've pointed out on the basis of the scientific evidence is that there are certain diets that have a lower carbon footprint — Jim Skea."

— Jim Skea. SRCCL Facebook 8 August 2019

Chapter 6, "Interlinkages between desertification, land degradation, food security and GHG fluxes: Synergies, trade-offs and Integrated Response Options", offers pathways of mitigating the effects of global climate change on land use, such as reduced deforestation and agricultural diversification. In addition, Chapter 6 also says that a shift in consumer behaviour towards a more plant-based diet with less protein from livestock, such as cattle, "sheep, buffalo and goats" would result in lower emissions. One of the three lead authors for Chapter 6, the University of Aberdeen's environmental scientist, Pete Smith, who teaches plant and soil science, said that as growing conditions deteriorate, there will be a "massive pressure for migration." Ruminant livestock not only produce a lot of methane, a powerful greenhouse gas, but the "deforestation in critical forest systems" is caused by need for grazing land in countries such as Brazil. Smith clarified that, "We're not telling people to stop eating meat. In some places people have no other choice. But it's obvious that in the West we're eating far too much."

Rutgers University's Department of Human Ecology at the School of Environmental and Biological Sciences's associate professor, Pamela McElwee, who is one of Chapter 6's co-authors, said that "dietary change"—"particularly in developed countries of the West"—such as reducing "excess" consumption of "high-greenhouse-gas-emissions diets" high in lamb and cattle consumption is a "win-win" because it addresses both climate crisis and health problems at the same time. McElwee said that food security in a warming world is a major concern as there is potential for "food crises developing "on several continents at once," as quoted in the New York Times. Climate change can be a multiplier effect on existing problems like "rate of soil loss and land degradation" which heightens the risk of "severe food shortages." While there are a lot of actions available to combat these problems, McElwee said that "what some of these solutions do require is attention, financial support, enabling environments." The science on which the report is based shows that "increasing the productivity of land, wasting less food" and shifting diets "away from cattle and other types of meat" lowers the carbon footprint. According to an 8 August 2019 PBS NewsHour report, about 15% of current emissions could be cut by mid-century if "people change their diets, reducing red meat and increasing plant-based foods, such as fruits, vegetables and seeds." Rosenzweig added, it "would also make people more healthy."

Chapter six discusses material substitution as it relates to sustainable long-term forest management, with more production of harvested wood products (HWPs) which have a lower carbon footprint. HWP that are used to as a substitute for metal, plastic, or concrete— which are more emissions-intensive—would also result in removing carbon dioxide (CO₂) from the atmosphere. In Canada, for example, Margot Hurlbert said that forest industry could increase the percentage of solid wood products that it harvests and decrease the amount of pulp and paper products.

Chapter 7: Risk management and decision making in relation to sustainable development

Risk management, which "reduces vulnerabilities in land and the food system" and increases resilience in communities, can include making dietary changes and growing a "variety of crops", which can prevent soil degradation. It also includes sharing risks, "reducing inequalities, and improving incomes." Other "ways to adapt to the negative effects of climate change, include ensuring that there is "equitable access to food" particularly in those regions where "land cannot provide adequate food".

University of Regina's Margot Hurlbert, who is also Canada Research Chair in climate change, energy and sustainability policy, is co-ordinating co-author of "Risk management and decision making in relation to sustainable development", said that, "...there's lots of opportunities to make these changes, and it's not too late." This includes using natural shade, through agroforestry, for example, to grow crops, and—in tropical climates—using biochar as a fertilizer. Hurlbert said that countries, like Canada, can "wield influence through its own use of trade conditions and policies" to "ensure imported food is grown without damaging landscapes and widening deserts overseas". Consumers, as well as organizations and governments, can use sustainability certifications when sourcing wood products and food, for example.

Main statements

"Land is where we live. Land is under growing human pressure. Land is a part of the solution. But land can't do it all."

— IPCC. 9 August 2019. Twitter

This report provided a comprehensive overview of the entire land-climate system for the first time and addressed land itself as a "critical resource".

In a 9 August United Nations video, Valerie Masson-Delmotte cited the newly released report, saying that there are currently over 500 million people who live in areas negatively affected by climate change on land transformed by land degradation or desertification. Many are forced to migrate. The international group of 107 authors urged all nations to adopt sustainable land use in order to "limit greenhouse gas emissions before it is too late" and to work together to build long-term food security systems to support farmers with programs that will help build their resilience and help them engage in the market.

IPCC vice-chair and ANU Climate Institute director Mark Howden, who is one of the authors of the SRCCL, said that "the land sector is currently contributing to climate change" and better land management "would have multiple economic, environmental and health benefits" and would deliver "win-wins for farmers, communities, governments and biodiversity but also helps address climate change."

Contributors

The scientific leadership of the SRCCL included 107 experts from 52 countries as coordinating lead authors and lead authors in the three IPCC Working Groups as well as the Task Force on National Greenhouse Gas Inventories with support from the Working Group III Technical Support Unit. Fifty three percent of the authors of the report are from developing countries and forty percent of the coordinating lead authors are women.

Reactions

The Economist stated that the report "fires another warning shot about the state of the planet and the way people are transforming virtually every corner of every continent. Human activities affect roughly three-quarters of Earth's ice-free land, with huge consequences for the climate." The BBC published a series of articles related to the publication of the report. Roger Harrabin, a BBC environment analyst, said that the report would "become the most authoritative report yet on the way we use and abuse the land." An 8 August 2019 article by New York Times (NYT) highlighted the facts that the SRCCL was "prepared by more than 100 experts from 52 countries" and that it found that a "half-billion people already live in places turning into desert, and soil is being lost between 10 and 100 times faster than it is forming." The NYT also pointed to the fivefold increase in migrants at the United States/Mexico border from El Salvador, Guatemala and Honduras "coinciding with a dry period that left many with not enough food." Some scientists "suggested it bears the signal of climate change." An article in The Atlantic was titled, "This Land Is the Only Land There Is". The article said that the SRCCL is a milestone because it says that ice-free land itself, which humans need for growing food, is "scarce and precious". The article pointed to some climate scientists and researchers having, prior to SRCCL, sometimes portrayed land as a "limitless" cleansing "global sponge", in the sense that replanting sufficient numbers of trees would significantly reduce the net CO₂ burden. The Washington Post called SRCCL a "landmark study".

Deforestation and climate change

From Wikipedia, the free encyclopedia

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

Deforestation in the tropics – given as the annual average between 2010 and 2014 – was responsible for 2.6 billion tonnes of CO₂ per year. That was 6.5% of global CO₂ emissions.

Deforestation is a primary contributor to climate change, and climate change affects the health of forests. Land use change, especially in the form of deforestation, is the second largest source of carbon dioxide emissions from human activities, after the burning of fossil fuels. Greenhouse gases are emitted from deforestation during the burning of forest biomass and decomposition of remaining plant material and soil carbon. Global models and national greenhouse gas inventories give similar results for deforestation emissions. As of 2019, deforestation is responsible for about 11% of global greenhouse gas emissions. Carbon emissions from tropical deforestation are accelerating.

When forests grow they are a carbon sink and therefore have potential to mitigate the effects of climate change. Some of the effects of climate change, such as more wildfires, invasive species, and extreme weather events can lead to more forest loss. The relationship between deforestation and climate change is one of a positive (amplifying) climate feedback. The more trees that are removed, the greater the effect of climate change which then results in the loss of more trees.

Forests cover 31% of the land area on Earth. Every year, 75,700 square kilometers (18.7 million acres) of the forest is lost. There was a 12% increase in the loss of primary tropical forests from 2019 to 2020.

Deforestation has many causes, among them agricultural clearcutting, livestock grazing, logging for timber, and wildfires.

Causes of deforestation

Forest area net change rate per country in 2020

Causes due to climate change

The rate of global tree cover loss has approximately doubled since 2001, to an annual loss approaching an area the size of Italy.

Amazon slash-and-burn agriculture, Colombia

Globally, wildfires and deforestation have reduced forests' net absorption of greenhouse gases, reducing their effectiveness at mitigating climate change. Global warming increases forest fires that release more greenhouse gases, creating a feedback loop that causes more warming.

 

Over recent decades, "forest disturbance" (damage) by fire has increased in most of the planet's forest zones. The increase in area, frequency, and severity of forest fires creates a positive feedback that increases global warming.

Another cause of deforestation is due to the effects of climate change: More wildfires, insect outbreaks, invasive species, and more frequent extreme weather events (such as storms) are factors that increase deforestation.

A study suggests that "tropical, arid and temperate forests are experiencing a significant decline in resilience, probably related to increased water limitations and climate variability" which may shift ecosystems towards critical transitions and ecosystem collapses. By contrast, "boreal forests show divergent local patterns with an average increasing trend in resilience, probably benefiting from warming and CO₂ fertilization, which may outweigh the adverse effects of climate change". It has been proposed that a loss of resilience in forests "can be detected from the increased temporal autocorrelation (TAC) in the state of the system, reflecting a decline in recovery rates due to the critical slowing down (CSD) of system processes that occur at thresholds".

23% of tree cover losses result from wildfires and climate change increase their frequency and power. The rising temperatures cause massive wildfires especially in the Boreal forests. One possible effect is the change of the forest composition. Deforestation can also cause forests to become more fire prone through mechanisms such as logging.

Effects of deforestation on climate change

Biophysical mechanisms by which forests influence climate

Irreversible deforestation would result in a permanent rise in the global surface temperature. Moreover, it suggests that standing tropical forests help cool the average global temperature by more than 1 °C or 1.8 °F. Deforestation of tropical forests may risk triggering tipping points in the climate system and of forest ecosystem collapse which would also have effects on climate change.

Several studies since the early 1990s have shown that large-scale deforestation north of 50°N leads to overall net global cooling while tropical deforestation produces substantial warming. Carbon-centric metrics are inadequate because biophysical mechanisms other than CO₂ impacts are important, especially the much higher albedo of bare high-latitude ground vis-à-vis intact forest.

Deforestation, particularly in large swaths of the Amazon, where nearly 20% of the rainforest has been clear cut, has climactic effects and effects on water sources as well as on the soil. Moreover, the type of land usage after deforestation also produces varied results. When deforested land is converted to pasture land for livestock grazing it has a greater effect on the ecosystem than forest to cropland conversions. Other effect of deforestation in the Amazon rainforest is seen through the greater amount of carbon dioxide emission. The Amazon rainforest absorbs one-fourth of the carbon dioxide emissions on Earth, however, the amount of CO₂ absorbed today decreases by 30% than it was in the 1990s due to deforestation.

Modeling studies have concluded that there are two crucial moments that can lead to devastating effects in the Amazon rainforest which are increase in temperature by 4 °C or 7.2 °F and deforestation reaching a level of 40%.

Forest fires

Main article: Wildfire

Statistics have shown a direct correlation between forest fires and deforestation. Statistics regarding the Brazilian Amazon area during the early 2000s have shown that fires and the air pollution that accompanies these fires mirror the patterns of deforestation and "high deforestation rates led to frequent fires".

The Amazon rainforest has experienced fires inside the forest as well as wildfires on its outer edges. Wetlands have faced an increase in forest fires as well. Due to the change in temperature, the climate around forests have become warm and dry, conditions that allow forest fires to occur.

Under unmitigated climate change, by the end of the century, 21% of the Amazon would be vulnerable to post‐fire grass invasion. In 3% of the Amazon, fire return intervals are already shorter than the time required for grass exclusion by canopy recovery, implying a high risk of irreversible shifts to a fire‐maintained degraded forest grassy state. The south‐eastern region of the Amazon is currently at highest risk of irreversible degradation.

According to a study in tropical peatland forest of Borneo, deforestation also contributes to the increase in fire risk.

Carbon sequestration through forestry

Further information: Carbon dioxide removal

Forests are an important part of the global carbon cycle because trees and plants absorb carbon dioxide through photosynthesis. Therefore, they play an important role in climate change mitigation. By removing the greenhouse gas CO₂ from the air, forests function as terrestrial carbon sinks, meaning they store large amounts of carbon in the form of biomass, encompassing roots, stems, branches, and leaves. By doing so, forests sequester approximately 25% of human carbon emissions annually, playing a critical role in Earth's climate. Throughout their lifespan, trees continue to sequester carbon, storing atmospheric CO₂ long-term. Sustainable forest management, afforestation, reforestation are therefore important contributions to climate change mitigation.

An important consideration in such efforts is that forests can turn from sinks to carbon sources. In 2019 forests took up a third less carbon than they did in the 1990s, due to higher temperatures, droughts and deforestation. National-scale forest inventory data also shows trends from 1999 to 2020 that some forests were already approaching climate thresholds shifting them from carbon sinks to carbon sources. The typical tropical forest may become a carbon source by the 2060s.

Researchers have found that, in terms of environmental services, it is better to avoid deforestation than to allow for deforestation to subsequently reforest, as the latter leads to irreversible effects in terms of biodiversity loss and soil degradation. Furthermore, the probability that legacy carbon will be released from soil is higher in a younger boreal forest. In particular, boreal forests have been noted to support the growth of Armillaria (honey fungus), which is a root pathogen that breaks down compounds necessary for wood integrity, increasing the likelihood of carbon release. Global greenhouse gas emissions caused by damage to tropical rainforests may have been substantially underestimated until around 2019. Additionally, the effects of afforestation and reforestation will be farther in the future than keeping existing forests intact. It takes much longer − several decades − for the benefits for global warming to manifest to the same carbon sequestration benefits from mature trees in tropical forests and hence from limiting deforestation. Therefore, scientists consider "the protection and recovery of carbon-rich and long-lived ecosystems, especially natural forests" to be "the major climate solution".

The planting of trees on marginal crop and pasture lands helps to incorporate carbon from atmospheric CO
₂ into biomass. For this carbon sequestration process to succeed the carbon must not return to the atmosphere from biomass burning or rotting when the trees die. Several species of Ficus such as Ficus wakefieldii have been observed to sequester atmospheric CO₂ as calcium oxalate in the presence of oxalotrophic bacteria and fungi, which catabolize the oxalate, which produces calcium carbonate. The calcium carbonate is precipitated throughout the tree, which also alkalinizes the surrounding soil. These species are current candidates for carbon sequestration in agroforestry. This Calcium-oxalate fixation process was first observed in the Iroko tree, which can sequester up to a ton of calcium carbonate in the soil over its lifespan. Also Cacti, such as the Saguaro, transfer carbon from the biological cycle to the geological cycle by forming the mineral calcium carbonate.

Earth offers enough room to plant an additional 0.9 billion ha of tree canopy cover, although this estimate has been criticized, and the true area that has a net cooling effect on the climate when accounting for biophysical feedbacks like albedo is 20-80% lower. Planting and protecting these trees would sequester 205 billion tons of carbon if the trees survive future climate stress to reach maturity. To put this number into perspective, this is about 20 years of current global carbon emissions (as of 2019). This level of sequestration would represent about 25% of the atmosphere's carbon pool in 2019.

Life expectancy of forests varies throughout the world, influenced by tree species, site conditions, and natural disturbance patterns. In some forests, carbon may be stored for centuries, while in other forests, carbon is released with frequent stand replacing fires. Forests that are harvested prior to stand replacing events allow for the retention of carbon in manufactured forest products such as lumber. However, only a portion of the carbon removed from logged forests ends up as durable goods and buildings. The remainder ends up as sawmill by-products such as pulp, paper, and pallets. If all new construction globally utilized 90% wood products, largely via adoption of mass timber in low rise construction, this could sequester 700 million net tons of carbon per year. This is in addition to the elimination of carbon emissions from the displaced construction material such as steel or concrete, which are carbon-intense to produce.

A meta-analysis found that mixed species plantations would increase carbon storage alongside other benefits of diversifying planted forests.

Although a bamboo forest stores less total carbon than a mature forest of trees, a bamboo plantation sequesters carbon at a much faster rate than a mature forest or a tree plantation. Therefore, the farming of bamboo timber may have significant carbon sequestration potential.

The Food and Agriculture Organization (FAO) reported that: "The total carbon stock in forests decreased from 668 gigatonnes in 1990 to 662 gigatonnes in 2020". In Canada's boreal forests as much as 80% of the total carbon is stored in the soils as dead organic matter.

The IPCC Sixth Assessment Report says: "Secondary forest regrowth and restoration of degraded forests and non-forest ecosystems can play a large role in carbon sequestration (high confidence) with high resilience to disturbances and additional benefits such as enhanced biodiversity."

Impacts on temperature are affected by the location of the forest. For example, reforestation in boreal or subarctic regions has less impact on climate. This is because it substitutes a high-albedo, snow-dominated region with a lower-albedo forest canopy. By contrast, tropical reforestation projects lead to a positive change such as the formation of clouds. These clouds then reflect the sunlight, lowering temperatures.

Planting trees in tropical climates with wet seasons has another advantage. In such a setting, trees grow more quickly (fixing more carbon) because they can grow year-round. Trees in tropical climates have, on average, larger, brighter, and more abundant leaves than non-tropical climates. A study of the girth of 70,000 trees across Africa has shown that tropical forests fix more carbon dioxide pollution than previously realized. The research suggested almost one-fifth of fossil fuel emissions are absorbed by forests across Africa, Amazonia and Asia. Simon Lewis stated, "Tropical forest trees are absorbing about 18% of the carbon dioxide added to the atmosphere each year from burning fossil fuels, substantially buffering the rate of change."

Concerns with forestry projects

This section is an excerpt from Carbon offsets and credits § Concerns with forestry projects.[edit]

Forestry projects have faced increasing criticism over their integrity as offset or credit programs. A number of news stories from 2021 to 2023 criticized nature-based carbon offsets, the REDD+ program, and certification organizations. In one case it was estimated that around 90% of rainforest offset credits of the Verified Carbon Standard are likely to be "phantom credits".

Tree planting projects in particular have been problematic. Critics point to a number of concerns. Trees reach maturity over a course of many decades. It is difficult to guarantee how long the forest will last. It may suffer clearing, burning, or mismanagement. Some tree-planting projects introduce fast-growing invasive species. These end up damaging native forests and reducing biodiversity. In response, some certification standards such as the Climate Community and Biodiversity Standard require multiple species plantings. Tree planting in high latitude forests may have a net warming effect on the Earth's climate because tree cover absorbs sunlight thus creating a warming effect that balances out their absorption of carbon dioxide. Tree-planting projects can also cause conflicts with local communities and Indigenous people if the project displaces or otherwise curtails their use of forest resources.

Changes in rainfall

Further information: Flying river

As a consequence of reduced evapotranspiration, precipitation is also reduced. This implies having a hotter and drier climate, and a longer dry season. This change in climate has drastic ecological and global impacts including increases in severity and frequency of fires, and disruption in the pollination process that will likely spread beyond the area of deforestation.

According to a study published in 2023, tropical deforestation has led to a significant decrease in the amount of observed precipitation. By the year 2100, researchers anticipate that deforestation in the Congo will diminish regional precipitation levels by up to 8-10%.

Decreasing albedo

Deforestation changes the landscape and reflectivity of earth's surface, i.e. decreasing Albedo. This results in an increase in the absorption of light energy from the sun in the form of heat, enhancing global warming.

Policies and programs to reduce deforestation

Main article: Deforestation § Control

Deforestation in Bolivia

Reducing emissions from deforestation and forest degradation in developing countries

Examples of issues addressed by REDD+ in tropical forest landscapes: large-scale deforestation visible from space (top), conversion of carbon-rich peat forests for agriculture such as oil-palm (left), and community-based efforts to reduce forest degradation by creating income incentives for conservation (right).

REDD+ is a voluntary climate change mitigation framework developed under the United Nations Framework Convention on Climate Change (UNFCCC). It aims to encourage developing countries to reduce greenhouse gas emissions from deforestation and forest degradation, and to promote conservation, sustainable forest management, and enhancement of forest carbon stocks through financial incentives and policy support. The acronym is commonly expanded as "reducing emissions from deforestation and forest degradation in developing countries", and the "+" denotes the additional forest conservation and enhancement activities included in the UNFCCC scope.

UNFCCC decisions describe REDD+ as a phased approach, beginning with "readiness" activities (planning, capacity-building and institutional development), moving to implementation of national policies and measures, and evolving toward results-based actions that are fully measured, reported and verified. Countries undertaking REDD+ are expected to develop a national strategy or action plan, establish a forest reference (emission) level (FREL/FRL) as a benchmark for assessing performance, and build a national forest monitoring system to support monitoring, reporting and verification (MRV). UNFCCC decisions also include social and environmental safeguards (often referred to as the Cancún safeguards) and require countries seeking results-based payments to provide information on how safeguards are addressed and respected.

REDD+ is supported through a mix of multilateral and bilateral channels and can receive results-based finance when reported results meet UNFCCC methodological and transparency requirements under the Warsaw Framework on REDD-plus. A 2024 multi-country impact evaluation reported modest average forest outcomes and limited average welfare effects, with impacts not always sustained over time. Reviews and methodological assessments highlight uncertainties in baselines (reference levels), additionality, leakage, non-permanence and measurement capacity, especially for forest degradation and carbon pools that are harder to quantify. Criticisms and controversies also focus on governance and equity issues, including land tenure and carbon rights, benefit sharing, and the participation and consent of Indigenous peoples and local communities, alongside broader debates over the role of forest offsets in climate policy.

REDD+ remains an active part of the UNFCCC and Paris Agreement architecture. Most of the core UNFCCC decisions that define REDD+ were adopted between 2010 and 2015, including the Warsaw Framework on REDD-plus (2013). Countries continue to report REDD+ results through technical annexes to developing-country reports, including under the Paris Agreement's enhanced transparency framework via technical annexes to biennial transparency reports (BTRs). Results-based finance also continues through multilateral channels such as the Green Climate Fund's REDD+ results-based payments window.

The Bali Action Plan

Scioto grove reforestation area

The Bali Action Plan was developed in December 2007 in Bali, Indonesia. It is a direct result of the Kyoto Protocol of December 1997. One of the key elements of The Bali Action Plan involves a concerted effort by the member countries of the Kyoto Protocol to enact and create policy approaches that incentivize emissions reduction caused by deforestation and forest degradation in the developing world. It emphasized the importance of sustainable forest management and conservation practices in mitigating climate change. This coupled with the increased attention to carbon emission stocks as a way to provide additional resource flows to the developing countries.

Trillion Tree Campaign

Main article: Trillion Tree Campaign

Afforestation at Kanakakunnu

The Billion Tree Campaign was launched in 2006 by the United Nations Environment Programme (UNEP) as a response to the challenges of climate change, as well as to a wider array of sustainability challenges, from water supply to biodiversity loss. Its initial target was the planting of one billion trees in 2007. Only one year later in 2008, the campaign's objective was raised to 7 billion trees—a target to be met by the climate change conference that was held in Copenhagen, Denmark in December 2009. Three months before the conference, the 7 billion planted trees mark had been surpassed. In December 2011, after more than 12 billion trees had been planted, UNEP formally handed management of the program over to the not-for-profit Plant-for-the-Planet initiative, based in Munich, Germany.

The Amazon Fund (Brazil)

Four-year plan to reduce in deforestation in the Amazon

The Amazon Fund (in Portuguese: Fundo Amazônia) is an initiative created by the Brazilian Government and managed by the National Bank for Economic and Social Development (BNDES). It was established on 1 August 2008, with the aim of attracting donations for non-reimbursable investments in actions for the prevention, monitoring, and combat of deforestation, and for the promotion of conservation and sustainable use of the Amazon rainforest. Additionally, the fund supports the development of monitoring and control systems for deforestation in the rest of Brazil and in other tropical countries.

The fund is used in various areas, including the management of public forests and protected areas, control, monitoring and environmental enforcement, sustainable forest management, economic activities developed from the sustainable use of the forest, ecological and economic zoning, land planning and regularization, conservation and sustainable use of biodiversity, and the recovery of deforested areas. The projects supported by the fund must be aligned with applicable public policies and the guidelines and criteria, in addition to demonstrating their direct or indirect contribution to the reduction of deforestation and forest degradation. The actions foreseen in the projects must be coherent with the proposed objective, with the budget and with the schedule of its implementation. Eligibility for accessing the Amazon Fund is determined based on compliance with several plans and criteria, including the PPCDAm (Action Plan for Prevention and Control of Deforestation in the Legal Amazon Region), ENREDD+ (National Strategy for REDD+), state plans for preventing and combating deforestation, and BNDES Operational Policies. Projects eligible for funding should directly or indirectly contribute to reducing deforestation in the Amazon. Various types of entities can submit projects for funding, including public administration bodies, NGOs, private companies, cooperatives, and research institutions.

Until 2018, the fund received R$ 3.4 billion in donations, with the majority coming from Norway, followed by Germany and Petrobras. Since 2023, several countries announced contributions to the fund or interest in contributing, including Germany, Norway, the United States, the United Kingdom, Switzerland, Denmark, France, Spain, Japan and others.