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Rainforest Promises | Earth Wise

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The recent UN climate summit in Sharm el Sheikh, Egypt brought with it lots of pledges for action.   Among them was a promise from the three countries that are home to more than half of the world’s tropical rainforests to try to do something to protect them.

The ministers of Brazil, Indonesia, and the Democratic Republic of Congo signed an agreement pledging cooperation on sustainable management and conservation, restoration of critical ecosystems, and creation of economies that would ensure the health of both their people and their forests.

The plan has no financial backing of its own.  The countries are pledging to work together to establish a funding mechanism that could help to preserve the tropical forests that both help regulate the Earth’s climate and sustain a wide range of animals, plants, birds, and insects.

That such an agreement has come about at all is a result of the election of Luiz Lula da Silva as Brazilian president, replacing Jair Bolsonaro, who was famously an opponent of any and all environmental conservation or protections.  President Lula addressed the attendees of the climate summit promising that “Brazil is back.”   He described his country as having been in a cocoon for the past four years under his predecessor.  He declared that going forward, Brazil will be a force to combat climate change.  Given the importance of the Amazon rainforest, that is critical for the success of the world’s efforts.

Like all other issues on the table at the climate summit, the real challenge is not to come up with meaningful pledges on climate action, it is to be able to follow through on those pledges.  If past summits are any indication, that is not an easy task.

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Brazil, Indonesia and Congo Sign Rainforest Protection Pact

Photo, posted September 15, 2013, courtesy of Moises Silva Lima via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Mangrove Forests And Climate Change | Earth Wise

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Mangrove forests play a vital role in the health of our planet.  These coastal forests are the second most carbon rich ecosystems in the world.  A patch of mangrove forest the size of a soccer field can store more than 1,000 tons of carbon. It does this by capturing carbon from the air and storing it in leaves, branches, trunks, and roots.

Mangrove forests only grow at tropical and subtropical latitudes near the equator because they cannot withstand freezing temperatures.  These forests can be recognized by their dense tangle of prop roots that make the trees look like they are standing on stilts above the water.  These roots allow the trees to handle the daily rise and fall of tides.  Most mangroves get flooded at least twice a day.  The roots also slow the movement of tidal waters, which allows sediments to settle out of the water and build up on the muddy bottom.  Mangrove forests stabilize coastlines, reducing erosion from storms, currents, waves, and tides.

A new study by the University of Portsmouth in the UK looked at the effects of climate change on how carbon is stored in mangrove forests.  In mangrove ecosystems, a variety of organisms break down fallen wood.  These include fungi, beetle larvae, and termites.  Closer to the ocean, clams known as shipworms degrade organic material.

Climate change is disrupting these processes in at least two ways.  Rising sea levels are changing the way sediments build up and increased ocean acidity is dissolving the shells of marine organisms like shipworms.

Mangrove forests are crucial to mitigating climate change, and changes to the functioning of the carbon cycle of those ecosystems are a threat to their ability to perform that function.

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Study Reveals How Climate Change Can Significantly Impact Carbon-Rich Ecosystem

Photo, posted March 24, 2014, courtesy of Daniel Hartwig via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Training Corals To Tolerate Heat | Earth Wise

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When ocean water is too warm, corals expel the algae that lives in their tissues, which causes the coral to turn completely white.  This is called coral bleaching.   When this happens, the coral is not dead.  However, corals are dependent upon the symbiotic relationship with algae and if conditions don’t improve, they don’t let the algae back in and the corals will die.

According to the National Oceanic and Atmospheric Administration, between 2014 and 2017, around 75% of the world’s tropical coral reefs experienced heat stress severe enough to trigger bleaching.  For 30% of the world’s reefs, the heat stress was enough to kill the coral.

According to new research by the University of Miami published in the journal Coral Reefs, corals subjected to a stressful regimen of very warm water in the laboratory came to be more tolerant of high temperatures, offering a potential tool for preserving ailing coral reefs.

In the study, some corals were kept in water at a constant temperature of 82 degrees while others saw water temperatures fluctuating between 82 degrees and 88 degrees.  After 90 days of this treatment, the corals exposed to variable temperatures were able to tolerate high heat for longer periods before bleaching.  This training regime is akin to an athlete preparing for a race.

The findings suggest a possible approach for restoring coral reefs.  Nursery-raised corals that are “trained” to tolerate heat could be planted onto reefs endangered by warming waters.  Reefs populated by corals with boosted stamina to heat stress could have a greater chance of surviving the warming waters of the oceans.

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Some Corals Can Be Conditioned to Tolerate Heat, Study Finds

Photo, posted December 16, 2015, courtesy of Big Cypress National Preserve via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Tree Diversity | Earth Wise

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Scientists have estimated that there are more than 8 million species of plants and animals in existence.  Amazingly, only about 1.2 million of them have been identified and described so far and most of those are actually insects.  Millions of other organisms have yet to be discovered.

One would imagine that most of these unknown species are tiny things that are hard to spot or encounter.  But our ignorance of species even applies to trees, which are pretty easy to spot if you encounter them.

A new study involving more than 100 scientists across the globe has produced an estimate of the number of tree species on the Earth.  The new global estimate is that there are 73,000 tree species, which is about 14% more than previously thought.  Based on a combination of data from two global datasets, the study yielded a total of 64,100 documented tree species worldwide.  The researchers then used novel statistical methods to estimate the total number of unique tree species at biome, continental, and global scales, which includes species yet to be discovered and described by scientists.  Therefore, the estimate predicts that there are likely to be over 9,000 tree species still to be found.

Roughly 40% of the undiscovered tree species are likely to be in South America, which is the continent with the highest number of rare tree species and the highest number of continentally endemic tree species – meaning those found only on that continent.  Hot spots of undiscovered tree species are likely the tropical and subtropical moist forests of the Amazon basin and the Andes-Amazon interface.

Extensive knowledge of tree richness and diversity is key to preserving the stability and functioning of ecosystems.

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Number of Earth’s tree species estimated to be 14% higher than currently known, with some 9,200 species yet to be discovered

Photo, posted November 5, 2017, courtesy of Deensel via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Bomb Cyclones | Earth Wise

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It seems like we are hearing about new weather phenomena pretty frequently these days.  One name that has popped up lately is “bomb cyclones.”  Bomb cyclones, it turns out, are storms that undergo “bombogenesis.”  What that means is a low-pressure area (in other words, a storm) that undergoes rapid strengthening and can be described as a weather bomb, or popularly, a bomb cyclone.

These things usually take place over remote tropical ocean areas but a really intense one struck the Pacific Northwest on October 24th.  The storm off the coast of Washington, with a barometric pressure reading equivalent to a category 4 hurricane, was the second extreme low-pressure storm in the North Pacific in a single week.  Both storms involved pressure drops of more than 24 millibars in 24 hours, making them bomb cyclones.

These storms brought high winds and extreme precipitation that doused wildfires and provided some relief to the extreme drought in Central and Northern California.  Along with these positive effects, however, the storms also caused power outages, flooding, landslides, and mud and debris that washed out roads.

The October 24-25 event brought 16.55 inches of rain to Mount Tamalpais in Marin County, California in a 48-hour period.  Sacramento got 5.44 inches of rain, breaking a 140-year-old record.  And the city had just broken another extreme weather record for the longest dry spell in history.

The storms directed streams of moisture from north of Hawaii toward the West Coast in long, narrow bands of moisture known as atmospheric rivers.  We are learning about all sorts of unfamiliar weather phenomena as extreme weather events become increasingly common.

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Extratropical Cyclones Drench West Coast

Photo, posted January 4, 2018, courtesy of NOAA/CIRA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Disappearing Mountaintop Glacier Ice | Earth Wise

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A newly released study has found that mountaintop glacier ice in the tropics of all four hemispheres has diminished dramatically over the past 50 years.  Among the findings of the study, published in the journal Global and Planetary Change, are that a glacier near Puncak Jaya, in Papua New Guinea, lost about 93% of its ice between 1980 and 2018.  Between 1986 and 2019, the area covered by glaciers on top of Mt. Kilimanjaro in Africa decreased by nearly 75%.

The study combined NASA satellite imagery with data from ice cores drilled during field expeditions on tropical glaciers around the world.  The combination of measurements demonstrated that climate change is causing these glaciers to disappear and that the ice loss has accelerated in recent years.

The study looked at glacier ice in Kilimanjaro in Tanzania, the Andes in Peru and Bolivia, the Tibetan Plateau and the Himalayas, and ice fields in Papua, New Guinea.  Collecting ice cores from these places provides information on the climate in these regions over the centuries and millennia.  As snow falls on a glacier each year, it is buried and compressed to form layers that preserve the chemistry of snow, pollutants from the atmosphere, and biological material such as plants and pollen.

Glaciers in the tropics respond more quickly to climate change because they exist in the warmest areas of the world and survive only at very high altitudes. For many of these tropical glaciers, it is too late to prevent their demise.  It is not too late to attempt the slow down the buildup of greenhouse gases in the atmosphere that is causing the planet to warm, but we don’t have unlimited time to act.

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Mountaintop glacier ice disappearing in tropics around the world

Photo, posted February 12, 2009, courtesy of Christoph Strassler via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Palm Oil Replacement | Earth Wise

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In the 1990s, cardiovascular health issues associated with partially hydrogenated oils containing harmful trans fats became a focus of great concern.  As a result, food companies looked for substitutes and the alternative they identified was palm oil.  Its ability to remain solid at room temperature made it well suited for many food applications.  Unfortunately, that property stems from its high saturated fat content, which means it also increases the risk of coronary heart disease.

The widespread use of palm oil has also caused significant environmental problems.  Palm oil plantations have replaced millions of acres of tropical forests, destroying the habitat for numerous species and threatening biodiversity.

Other potential replacements for partially hydrogenated oils such as coconut oil tend to be more costly, limited in supply, and also high in saturated fats.

Food scientists at the University of Guelph in Ontario, Canada, recently demonstrated the use of enzymatic glycerolysis (EG) to turn liquid vegetable oils into solid fats.  Their process is able to produce solid fats with the textural and structural properties desired by consumers.

The process is fairly simple, relatively easy to scale up, and is amenable to smaller food production or even local production.  Using it would enable food producers to use all sorts of readily available vegetable oils that can be produced in parts of the world that are not necessarily tropical regions.

Palm oil use is not going to go away, but this work may point a way to help slow down the destruction of ecosystems and animal habitats as well lead to more sustainable and healthy food sources.

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U of G Food Scientists Find Palm Oil Alternative That’s Good for Human, Planet Health

Photo, posted February 21, 2010, courtesy of Craig Morey via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Restoring Tropical Forests | Earth Wise

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Tropical forests store more than half of the world’s above-ground carbon.  For this reason, deforestation is one of the greatest threats to global climate regulation.   Once forests are degraded through partial clearing and agricultural conversion, they are often perceived as no longer having much ecological value even though degraded forests still provide important ecosystem services despite no longer storing as much carbon.

As a result, once forests have been degraded, they tend to be seen as prime candidates for full conversion to agricultural plantations.   But this is not actually the case.

An international team of scientists, including researchers from Arizona State University’s Center for Global Discovery and Conservation Science, has provided the first long-term comparison of above-ground carbon recovery rates between naturally regenerating and actively restored forests in Southeast Asia.

First of all, the research shows that allowing forests to regenerate naturally results in significant amounts of restored above-ground carbon storage.  It is definitely worthwhile to allow forests to recover rather than giving up on them and putting the land to other uses.

But more importantly, the researchers found that forest areas that undergo active restoration recover their carbon-storing ability 50% faster than naturally recovering forests.

Restoration methods include planting native tree species and thinning vegetation around saplings to improve their chances of survival.   

These findings suggest that restoring tropical forests is a viable and highly scalable solution to regaining lost carbon stocks on land.  What is needed is sufficient incentive to engage in active forest restoration.  The current price of carbon is not sufficient to pay for restoration, but as the climate crisis intensifies, this is likely to change.

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Tempe to Hawaii: ASU professors teach Hawaiian youth about coral reef conservation

Photo, posted May 22, 2008, courtesy of Eric Chan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Mangrove Trees And Climate Change | Earth Wise

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Mangrove trees are small trees that grow in coastal saline or brackish water at tropical and subtropical latitudes.  Many mangrove trees can be identified by their dense tangle of prop roots.  These roots make the trees appear as if they are standing on stilts above the water.  The tangle of roots allows mangrove trees to handle the daily rise and fall of tides and to slow the movement of tidal waters.  

Mangrove forests provide many ecosystem services, including stabilizing the coastline by reducing erosion from storm surges, waves, and tides.  The intricate root system of mangrove trees are attractive to fish and other species seeking food and shelter from predators.  Mangrove forests also store large amounts of carbon.     

But according to a new study recently published in the journal Science, mangrove trees won’t survive sea level rise by 2050 if greenhouse gas emissions aren’t reduced.  

Using sediment data from 78 locations over the last 10,000 years, an international team of scientists led by Macquarie University in Australia estimated the chances of mangrove trees survival based on the projected rates of future sea-level rise.

When sea level rise rates exceeded 6 millimeters per year, which is similar to estimates under high-emissions scenarios for 2050, researchers found that mangrove trees were unlikely to keep pace with the rising water levels.  But when the annual increase was 5 millimeters or less – which is the projected low-emissions scenario this century – mangrove trees are much more likely to survive. 

These findings underscore the importance of reducing greenhouse gas emissions to mitigate rapid sea level rise.  The future of mangrove trees may depend on it.  

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Mangrove trees won’t survive sea-level rise by 2050 if emissions aren’t cut

Photo, posted December 17, 2012, courtesy of Edward Stojakovic via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Fighting Malaria With Gene-Drive Technology | Earth Wise

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Malaria continues to be a major health hazard throughout the tropical and subtropical regions of the world. There were 228 million cases of malaria in 2018 and over 400,000 deaths. 

Malaria is a mosquito-borne infectious disease spread by 40 of the world’s 3,500 mosquito species.  So, efforts to control mosquito populations are the primary strategy to eradicate malaria.

A team led by Imperial College London has created a genetic modification that distorts the sex ratio of a population of Anopheles gambiae mosquitoes using “gene drive” technology.  The modification works by using a DNA-cutting enzyme to destroy the X chromosome during the production of sperm, which leads to predominantly male offspring, since females require two X chromosomes.  The modification is coupled to a gene drive to allow it to spread through a population in a very effective way.  A gene drive is a genetic engineering technology that propagates a particular modification by assuring that a specific form of a gene (or allele) will be transmitted with far more than the natural 50% probability.

The result of this is that mosquitoes produce more male offspring, eventually leading to no females being born and a total collapse in the population. The mosquitoes studied are the main malaria vector in sub-Saharan Africa.  The hope is that mosquitoes carrying a sex-distorter gene drive would be released in the future, spreading the male bias with local malaria-carrying populations and causing them to collapse.  Only female mosquitoes bite and take blood meals.  If the gene drive technology works in the field, it could be a game-changer in the fight to eliminate malaria.

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Malaria mosquitoes eliminated in lab by creating all-male populations

Photo, posted June 20, 2014, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Forest Regrowth In The Amazon | Earth Wise

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The Amazon is the largest tropical rainforest in the world.  It covers an area approximately equal in size to the lower 48 states, and is home to an estimated 10% of the world’s biodiversity and 15% of its freshwater.  These so-called “lungs of the planet” provide many important global ecological services, including carbon storage, and regulating air quality and climate.

Deforestation in the Amazon exploded in the 1970s and remains one of its biggest threats today.  Since the 1970s, more than 20% of the Amazon rainforest has been cleared.  Cattle ranching, soy and palm plantations, logging, and climate change are some of the biggest drivers of deforestation.  

Now, according to a new study recently published in the journal Ecology, the regrowth of Amazonian forests following deforestation may happen more slowly than previously thought.  These findings could have significant impacts on climate change predictions as the ability of forest regrowth in the Amazon – so-called secondary forests – may have been overestimated.  The research, which was conducted in Bragança, Brazil and includes two decades of forest monitoring, reveals that climate change and the wider loss of forests could be hampering regrowth.    

After 60 years of regrowth, the research team found that secondary forests only held 40% of the carbon when compared with forests undisturbed by humans.  Secondary forests also take less carbon from the atmosphere during periods of drought, and climate change is increasing the number of drought-years in the Amazon.  (During their 20 years of monitoring, the researchers also found biodiversity levels in secondary forests were only 56% of those seen in undisturbed forests). 

More long-term studies are needed to better understand the impacts of reforestation efforts.  

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Amazon forest regrowth much slower than previously thought

Photo, posted September 6, 2009, courtesy of Nao Lizuka via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Mistaking Plastic For Food

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Green sea turtles are one of the world’s largest species of turtle, with some measuring close to four feet long and weighing up to nearly 300 pounds.  Their range extends throughout tropical and subtropical seas around the world, with the largest nesting populations found in Costa Rica and Australia. 

Green sea turtles get their name from the green layer of fat under their shell, as opposed to their shell itself, which can be brown, green, yellow, and/or black.  Scientists believe the green coloring of their fat is a result of their diet.  Unlike most other sea turtles, green sea turtles eat marine plants such as seaweed and seagrass.

But new research suggests that green sea turtles are also more likely to swallow plastic because it resembles their natural diet. The scientists from the University of Exeter and the Society for the Protection of Turtles who examined green sea turtles that washed up on beaches in Cyprus found they favored narrow lengths of plastic in natural colors (like green and black) as opposed to debris of other shapes and colors. 

Researchers were able to examine the full gastrointestinal tract of 19 green sea turtles.  They found pieces of plastic inside every one of them, with the number of pieces ranging from three to 183.  Smaller turtles tended to contain more plastic, possibly because they are less experienced or because diet choices change with age and size. 

Previous research has suggested that leatherback sea turtles also eat plastic that resembles their food: jellyfish. 

Researchers hope these findings will help motivate us to continue to work on reducing our overall plastic consumption and pollution.

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Green turtles eat plastic that looks like their food

Photo, posted September, 2007, courtesy of Brock Roseberry via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Economic Inequality

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A new study by Stanford University looked at the effects of climate change on global economic inequality.  The study found that the gap between the economic output of the world’s richest and poorest countries is larger today than it would have been without global warming.

The warming climate has enriched cooler countries like Norway and Sweden while dragging down economic growth in warm countries such as India and Nigeria.  The results of the study showed that most of the poorest countries on Earth are considerably poorer than they would have been in the absence of rising temperatures.  At the same time, the majority of rich countries are richer than they would have otherwise been.

Detailed analysis of 50 years of annual temperature and GDP measurements for 165 countries demonstrated that growth during warmer than average years has accelerated in cool nations and slowed in warm nations.  Historical data clearly show that crops are more productive, people are healthier, and they are more productive at work when temperatures are neither too hot nor too cold.  That means that in cold countries, a little bit of warming can help but the opposite is true in places that are already hot.

For most counties, whether global warming has helped or hurt economic growth is pretty certain.  Tropical countries in particular tend to have temperatures far outside the ideal for economic growth and they are already among the poorest countries.  It is less clear how warming has influenced growth in countries in the middle latitudes, such as here in the United States.  Some of the largest economies are near the perfect temperature for economic output but continued warming in the future is likely to push them away from the temperature optimum.

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Climate change has worsened global economic inequality

Photo, posted November 1, 2011, courtesy of CIAT via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Another Problem For Coral Reefs

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Coral reefs around the world have been suffering in recent years from warming ocean temperatures as well as from increasing ocean acidification.  Corals are very sensitive organisms that can only tolerate relatively slight changes in their environment.  Thus, the majority of reef-building corals are found in tropical and subtropical waters with favorable conditions.

New research has confirmed that drastic changes in ocean salinity from, for example, severe freshwater flooding, provoke similar stress responses in corals as the heating that has resulted in freshwater bleaching and, eventually, coral death.

The coast of northeast Queensland in Australia has experienced abnormal monsoon-related freshwater flooding that caused extreme and sudden changes in the ocean salt concentration.  In places, nearshore reefs were exposed to water with only half the normal ocean salinity.  The result has been a shock response in corals that prevents normal cell function.  Unlike their response to heat stress, corals exposed to reduced salinity experience a complete collapse of their internal cellular protein balance.

The central Great Barrier Reef has actually been relatively free from mass thermal bleaching events this Australian summer, but many coastal reefs instead have been battling dramatic changes in water conditions as a result of massive plumes of floodwater.

The wild weather in Australia is undoubtedly associated with the changing climate and this new research shows that it is leading to yet another threat to the world’s coral reefs.  With the frequency and severity of heavy rainfall and runoff events predicted to continue to increase over the next few decades, proactive measures to increase the resiliency of coral reefs are needed more than ever.

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Reduced salinity of seawater wreaks havoc on coral chemistry

Photo, posted December 12, 2010, courtesy of Gareth Williams via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Deforestation-Free Palm Oil

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Few of us cook with palm oil or have ever even seen the stuff.  Nevertheless, 50% of all packaged grocery items – everything from ice cream and pizza to detergents and cosmetics – include it as an ingredient.  The global market for palm oil was $65 billion in 2015, and that number was projected to grow by more than 7% each year through 2021.

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Indonesian Deforestation Continues

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Worldwide, deforestation and land disturbance are responsible for about a quarter of all greenhouse gas emissions.  The largest contributor to this problem is Indonesia and getting control of its emissions is a crucial part of meeting global carbon reduction targets.

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