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CLIMATE CHANGE THREATENS RAINFORESTS
By Rhett Butler | Last updated July 31, 2012
Global climate change initiated by global warming is expected to have wide-ranging effects for tropical rainforests
(also see section 9).
Changes in weather patterns, rainfall distribution, and temperature will result in the transformation of rainforest into drier forest in some areas and the conversion of other forms of forests into tropical forest. Should sea levels rise, large tracts of coastal lowland rainforest and enormous areas of mangrove forest will be affected. Additionally, though tropical forests and their species have lived through significant climate changes in the past (Pleistocene and Holocene epochs), they have less resilience to climate change in the future due to fragmentation and degradation from human activities. In response to global climate change, ecological communities will need to migrate, an effort that will be more difficult because of habitat alteration and fragmentation.
Climate models are still far from perfect, but recent simulations paint a mixed picture from tropical rainforests. In the Western Amazon, rainfall may increase, but the southern and eastern parts of the Amazon Basin are expected to experience higher temperatures and less rainfall. In Southeast Asia, warmer and drier conditions are projected for the island of Borneo. In contrast, parts of the African Sahel and coastal East Africa may have more precipitation. Most models project an increase in extreme weather with warming climate.
More information on the impacts of climate change on forests >>
Global warming accelerates destruction of the Amazon
40 percent of the Amazon could be grassland by 2050
Global warming will cause local climates to shift and disappear
Global warming could cause catastrophic die-off of the Amazon
Global warming could trigger 8-degree temperature rise in the Amazon
Globalization could save the Amazon rainforest
Expansion of agriculture in the Amazon may impact climate
Amazon drought continues, worst on record
Amazon rainforest locks up 11 years of carbon dioxide emissions
Subtle threats could destroy the Amazon rainforest
Review questions:
- How will climate change effect the distribution of rainforests?
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(07/12/2012) Recent blog posts on The Telegraph and the Register claiming that tropical rainforests like the Amazon are set to benefit from climate change are 'uninformed' and 'ridiculous' according to some of the world's most eminent tropical forest scientists. The posts, published Sunday and Monday by Tim Worstall, a Senior Fellow at London's Adam Smith Institute, asserted that a new Nature study indicates that 'climate change will mean new and larger tropical forests.' But some of the world's leading tropical forest experts took aim at Worstall's logic, noting the limitations of the study as well as the other factors that are endangering rainforests.
(02/21/2012) There may be less birds for birders to see in the world as the planet warms. Climate change, in combination with deforestation, could send between 100 and 2,500 tropical birds to extinction before the end of century, according to new research published in Biological Conservation. The wide range depends on the extent of climate and how much habitat is lost, but researchers say the most likely range of extinctions is between 600 and 900 species, meaning about 10-14 percent of tropical birds, excluding migratory species.
(02/01/2012) New, radical theories in science often take time to be accepted, especially those that directly challenge longstanding ideas, contemporary policy or cultural norms. The fact that the Earth revolves around the sun, and not vice-versa, took centuries to gain widespread scientific and public acceptance. While Darwin's theory of evolution was quickly grasped by biologists, portions of the public today, especially in places like the U.S., still disbelieve. Currently, the near total consensus by climatologists that human activities are warming the Earth continues to be challenged by outsiders. Whether or not the biotic pump theory will one day fall into this grouping remains to be seen. First published in 2007 by two Russian physicists, Victor Gorshkov and Anastassia Makarieva, the still little-known biotic pump theory postulates that forests are the driving force behind precipitation over land masses.
(05/20/2011) Deforestation and climate change will likely decimate much of the Amazon rainforest, says a new study by Brazil’s National Institute for Space Research (INPE) and the UK's Met Office Hadley Centre. Climate change and widespread deforestation is expected to cause warmer and drier conditions overall, reducing the resistance of the rainforest ecosystem to natural and human-caused stressors while increasing the frequency of extreme rainfall events and droughts by the end of this century. While climate models show that higher temperatures resulting from global climate change will threaten the resilience of the Amazon, current deforestation is an immediate concern to the rainforest ecosystem and is likely driving regional changes in climate.
(03/29/2011) A new study on its way to being published shows that the Amazon rainforest suffered greatly from last year's drought. Employing satellite data and supercomputing technology, researchers have found that the Amazon was likely hit harder by last year's drought than a recent severe drought from 2005. The droughts have supported predictions by the Intergovernmental Panel on Climate Change's (IPCC) that climate change, among other impacts, could push portions of the Amazon to grasslands, devastating the world's greatest rainforest. "The greenness levels of Amazonian vegetation—a measure of its health—decreased dramatically over an area more than three and one-half times the size of Texas and did not recover to normal levels, even after the drought ended in late October 2010," explains the study's lead author Liang Xu of Boston University.
(02/14/2011) How many tropical plant species are threatened by climate change? Which plants have big enough ranges to survive a warming world, not to mention deforestation? How likely is it that the tropics are undergoing a current mass extinction? These questions may appear straight forward, but a new study in Global Change Biology finds that researchers lack the hard data necessary to come to any confident conclusions. According to the study, nine out of ten tropical plants from Africa, Asia, and South America lack the minimum number of collections needed (at least 20) to determine the species' range, and therefore predict the impact of climate change.
(02/03/2010) A claim published in the Sunday Times over the veracity of a statement published in an Intergovernmental Panel on Climate Change (IPCC) report may land the British newspaper in hot water. On Sunday, Jonathan Leake, Science & Environment Editor of the Sunday Times, accused the IPCC of making a "bogus rainforest claim" when it cited a report warning that up to 40 percent of the Amazon could be "drastically" affected by climate change. Climate change skeptics immediately seized on "Amazongate" as further evidence to discredit the IPCC just two weeks after it was found to be using shoddy glacier data in its 2007 climate assessment.
(02/03/2010) Amid questions over the Amazon forests' capacity to survive climate change, a renowned tropical biologist says that in fact the fears are real, reports Tierramerica. Speaking at the Biodiversity Science Policy Conference in Paris, Thomas Lovejoy, biodiversity chair at the Washington DC-based Heinz Center for Science, Economics and the Environment, and chief biodiversity adviser to the president of the World Bank, described the Amazon rainforest as "very close to a tipping point".
(04/16/2009) Rising temperatures could reverse the role forests play in mitigating climate change, turning them into net sources of greenhouse gases, reports a new assessment by the International Union of Forest Research Organizations (IUFRO). The report, titled "Adaptation of Forests and People to Climate Change – A Global Assessment" and authored by 35 forestry scientists, examined the potential impacts of climate change across the world's major forest types as well as the capacity of forest biomes to adapt to climate shifts. Among the conclusions: a 2.5-degree-C rise in temperatures would eliminate the net carbon sequestering function of global forests. Presently forests worldwide capture about a quarter of carbon emissions.
(03/05/2009) Drought in the Amazon is imperiling the rainforest ecosystem and global climate, reports new research published in Science. Analyzing the impact of the severe Amazon drought of 2005, a team of 68 researchers across 13 countries found evidence that rainfall-starved tropical forests lose massive amounts of carbon due to reduced plant growth and dying trees. The 2005 drought — triggered by warming in the tropical North Atlantic rather than el Niño — resulted in a net flux of 5 billion tons of carbon dioxide (CO2) into the atmosphere — more than the combined annual emissions of Japan and Europe — relative to normal years when the Amazon is a net sink for 2 billion tons of CO2.
(02/19/2009) Economic development could doom the Amazon warns a comprehensive new report from the United Nations Environment Programme (UNEP). The report — titled GEO Amazonia [
(02/16/2009) Projections by the Intergovernmental Panel on Climate Change (IPCC) likely underestimate the scale and rapidity of climate change, warned a Stanford University scientist presenting Saturday at the annual meeting of the American Association for the Advancement of Science (AAAS) in Chicago.
(01/13/2009) A symposium from the Smithsonian Institution meant to debate the level of threat by deforestation posed to the tropics shifted topic slightly near its end as scientists began to discus which was the most significant threat for rainforests and the species that inhabit them: habitat destruction or climate change?
(02/27/2008) More than half the Amazon rainforest will be damaged or destroyed within 20 years if deforestation, forest fires, and climate trends continue apace, warns a study published in Philosophical Transactions of the Royal Society B. Reviewing recent trends in economic, ecological and climatic processes in Amazonia, Daniel Nepstad and colleagues forecast that 55 percent of Amazon forests will be "cleared, logged, damaged by drought, or burned" in the next 20 years. The damage will release 15-26 billion tons of carbon into the atmosphere, adding to a feedback cycle that will worsen both warming and forest degradation in the region. While the projections are bleak, the authors are hopeful that emerging trends could reduce the likelihood of a near-term die-back. These include the growing concern in commodity markets on the environmental performance of ranchers and farmers; greater investment in fire control mechanisms among owners of fire-sensitive investments; emergence of a carbon market for forest-based offsets; and the establishment of protected areas in regions where development is fast-expanding.
