Tag Archives: tropical rainforests

How Forests Create Clouds and Cool the Earth

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Tropical forests have a crucial role in cooling Earth’s surface by extracting carbon dioxide from the air. But only two-thirds of their cooling power comes from their ability to suck in CO2 and store it. The other one-third comes from their ability to create clouds, humidify the air and release cooling chemicals. This is a larger contribution than expected for these ‘biophysical effects’ says Bronson Griscom, a forest climate scientist.

The analysis, published in Frontiers in Forests and Global Change in March 2022, could enable scientists to improve their climate models, while helping governments to devise better conservation and climate strategies. The findings underscore growing concerns about rampant deforestation across the tropics. Scientists warn that one-third of the world’s tropical forests have been mown down in the past few centuries, and another one-third has been degraded by logging and development. This, when combined with climate change, could transform vast swathes of forest into grasslands…

Trees in the tropics provide shade, but they also act as giant humidifiers by pulling water from the ground and emitting it from their leaves, which helps to cool the surrounding area in a way similar to sweating, Griscom says. “If you go into a forest, it immediately is a considerably cooler environment,” he says.

This transpiration, in turn, creates the right conditions for clouds, which like snow and ice in the Arctic, can reflect sunlight higher into the atmosphere and further cool the surroundings. Trees also release organic compounds — for example, pine-scented terpenes — that react with other chemicals in the atmosphere to sometimes create a net cooling effect… When they considered only the biophysical effects, the researchers found that the world’s forests collectively cool the surface of the planet by around 0.5 °C.

Threats to tropical rainforests are dangerous not only for the global climate, but also for communities that neighbour the forests, Lawrence says. She and her colleagues found that the cooling caused by biophysical effects was especially significant locally. Having a rainforest nearby can help to protect an area’s agriculture and cities from heatwaves, Lawrence says. “Every tenth of a degree matters in limiting extreme weather. And where you have forests, the extremes are minimized.”

Excerpts from Freda Kreier, Tropical forests have big climate benefits beyond carbon storage, Nature, 

100 Ways to Finance Criminal Cartels Logging Forests

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The report – Green Carbon, Black Trade (2012) – by UNEP and INTERPOL focuses on illegal logging and its impacts on the lives and livelihoods of often some of the poorest people in the world set aside the environmental damage. It underlines how criminals are combining old fashioned methods such as bribes with high tech methods such as computer hacking of government web sites to obtain transportation and other permits. The report spotlights the increasingly sophisticated tactics being deployed to launder illegal logs through a web of palm oil plantations, road networks and saw mills. Indeed it clearly spells out that illegal logging is not on the decline, rather it is becoming more advanced as cartels become better organized including shifting their illegal activities in order to avoid national or local police efforts. By some estimates, 15 per cent to 30 per cent of the volume of wood traded globally has been obtained illegally…

The much heralded decline of illegal logging in the mid- 2000s in some tropical regions was widely attributed to a short-term law enforcement effort. However, long-term trends in illegal logging and trade have shown that this was temporary, and illegal logging continues. More importantly, an apparent decline in illegal logging is due to more advanced laundering operations masking criminal activities, and notnecessarily due to an overall decline in illegal logging. In many cases a tripling in the volumes of timber “originating” from plantations in the five years following the law enforcement crack-down on illegal logging has come partly from cover operations by criminals to legalize and launder illegal logging operations….

Much of the laundering of illegal timber is only possible due to large flows of funding from investors based in Asia, the EU and the US, including investments through pension funds. As funds are made available to establish plantations operations to launder illegal timber and obtain permits illegally or pass bribes, investments, collusive corruption and tax fraud combined with low risk and high demand, make it a highly profitable illegal business, with revenues up to 5–10 fold higher than legal practices for all parties involved. This also undermines subsidized alternative livelihood incentives available in several countries.

[It is important to discourage] the use of timber from these regions and introducing a rating og companies based on the likelihood of their involvement in illegal practices to discourage investors and stock markets from funding them.

Excerpts from Nellemann, C., INTERPOL Environmental Crime Programme (eds). 2012.Green Carbon, Black Trade Illegal Logging, Tax Fraud and Laundering in the Worlds Tropical Forests. A Rapid Response Assessment United Nations Environment Programme

How to Discover an Illegal Logger

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Tropical forests nearly the size of India are set to be destroyed by 2050 if current trends continue causing species loss, displacement and a major increase in climate-changing greenhouse gas emissions.  Prior to the launch of the Global Land Analysis and Discovery (GLAD) alerts, researchers would have to manually track images of logging in specific areas.

The new process, developed by scientists at the University of Maryland and Google, uses an algorithm to analyze weekly updates of satellite images and sends automatic notifications about new logging activity.”This is a game changer,” said Matt Finer from the Amazon Conservation Association, an environmental group.

His organization tracks illegal logging in Peru, sending images of deforestation to policymakers, environmentalists and government officials to try and protect the Amazon rainforest.  In the past, he would rely on tips from local people about encroachment by loggers, then look at older satellite images to try and corroborate the claims.

“With this new data we can focus on getting actionable information to policy makers,” Finer told the Thomson Reuters Foundation.  “We have seen how powerful these images can be,” he said, citing a case where his group brought pictures of illegal gold miners cutting down trees to the Peruvian government, who then removed the miners.

Excerpt from  CHRIS ARSENAULT, New satellite program aims to cut down illegal logging in real time, Reuters, Mar. 2, 2016

The Desert at the Heart of the Amazon Rainforest

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An area of the Amazon rainforest twice the size of California continues to suffer from the effects of a megadrought that began in 2005, finds a new NASA-led study. These results, together with observed recurrences of droughts every few years and associated damage to the forests in southern and western Amazonia in the past decade, suggest these rainforests may be showing the first signs of potential large-scale degradation due to climate change.

An international research team led by Sassan Saatchi of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., analyzed more than a decade of satellite microwave radar data collected between 2000 and 2009 over Amazonia. The observations included measurements of rainfall from NASA’s Tropical Rainfall Measuring Mission and measurements of the moisture content and structure of the forest canopy (top layer) from the Seawinds scatterometer on NASA’s QuikScat spacecraft.

The scientists found that during the summer of 2005, more than 270,000 square miles (700,000 square kilometers, or 70 million hectares) of pristine, old-growth forest in southwestern Amazonia experienced an extensive, severe drought. This megadrought caused widespread changes to the forest canopy that were detectable by satellite. The changes suggest dieback of branches and tree falls, especially among the older, larger, more vulnerable canopy trees that blanket the forest.

While rainfall levels gradually recovered in subsequent years, the damage to the forest canopy persisted all the way to the next major drought, which began in 2010. About half the forest affected by the 2005 drought – an area the size of California – did not recover by the time QuikScat stopped gathering global data in November 2009 and before the start of a more extensive drought in 2010.

“The biggest surprise for us was that the effects appeared to persist for years after the 2005 drought,” said study co-author Yadvinder Malhi of the University of Oxford, United Kingdom. “We had expected the forest canopy to bounce back after a year with a new flush of leaf growth, but the damage appeared to persist right up to the subsequent drought in 2010.”

Recent Amazonian droughts have drawn attention to the vulnerability of tropical forests to climate change. Satellite and ground data have shown an increase in wildfires during drought years and tree die-offs following severe droughts. Until now, there had been no satellite-based assessment of the multi-year impacts of these droughts across all of Amazonia. Large-scale droughts can lead to sustained releases of carbon dioxide from decaying wood, affecting ecosystems and Earth’s carbon cycle.

The researchers attribute the 2005 Amazonian drought to the long-term warming of tropical Atlantic sea surface temperatures. “In effect, the same climate phenomenon that helped form hurricanes Katrina and Rita along U.S. southern coasts in 2005 also likely caused the severe drought in southwest Amazonia,” Saatchi said. “An extreme climate event caused the drought, which subsequently damaged the Amazonian trees.”

Saatchi said such megadroughts can have long-lasting effects on rainforest ecosystems. “Our results suggest that if droughts continue at five- to 10-year intervals or increase in frequency due to climate change, large areas of the Amazon forest are likely to be exposed to persistent effects of droughts and corresponding slow forest recovery,” he said. “This may alter the structure and function of Amazonian rainforest ecosystems.”

The team found that the area affected by the 2005 drought was much larger than scientists had previously predicted. About 30 percent (656,370 square miles, or 1.7 million square kilometers) of the Amazon basin’s total current forest area was affected, with more than five percent of the forest experiencing severe drought conditions. The 2010 drought affected nearly half of the entire Amazon forest, with nearly a fifth of it experiencing severe drought. More than 231,660 square miles (600,000 square kilometers) of the area affected by the 2005 drought were also affected by the 2010 drought. This “double whammy” by successive droughts suggests a potentially long-lasting and widespread effect on forests in southern and western Amazonia.

The drought rate in Amazonia during the past decade is unprecedented over the past century. In addition to the two major droughts in 2005 and 2010, the area has experienced several localized mini-droughts in recent years. Observations from ground stations show that rainfall over the southern Amazon rainforest declined by almost 3.2 percent per year in the period from 1970 to 1998. Climate analyses for the period from 1995 to 2005 show a steady decline in water availability for plants in the region. Together, these data suggest a decade of moderate water stress led up to the 2005 drought, helping trigger the large-scale forest damage seen following the 2005 drought…

Results of the study were published recently in the Proceedings of the National Academy of Sciences. Other participating institutions included UCLA; University of Oxford, United Kingdom; University of Exeter, Devon, United Kingdom; National Institute for Space Research, Sao Jose dos Campos, Sao Paulo, Brazil; Boston University, Mass.; and NASA’s Ames Research Center, Moffett Field, Calif.

Study Finds Severe Climate Jeopardizing Amazon Forest, NASA Press Release, Jan. 17, 2013