But as forests burn and global warming worsens, the impact of Amazon deforestation continues to gradually undo the fragile ecological processes that have been refined over millions of years.

Ironically, as rainforest continues to disappear, scientific work from the last two decades has shed light on the critical ties that link the health of rainforests to the rest of the world.
 

Filtering and reprocessing the world’s harmful carbon dioxide output

Trees have hidden attributes that play a key role in reducing pollutant levels. Take carbon dioxide (CO₂) for example, a gas emitted from both natural and human sources. Over the last 150 years, humans have been pumping massive amounts of CO₂ into the air by burning fossil fuels, coal, oil and natural gas - this is a major driver for global climate change.

Carbon dioxide in, oxygen out
Under natural conditions, plants remove CO₂ from the atmosphere and absorb it for photosynthesis, an energy-creating process that yields:

• Oxygen, which is released back into the air
• Carbon, which allows the plant to grow.

So, without tropical rainforests the greenhouse effect would likely be even more pronounced, and climate change may possibly get even worse in the future.¹

Amazon rainforests and carbon dioxide
What forests take from the air, they can also give back. When forests burn, tree carbon matter is released in the form of CO₂, which pollutes the atmosphere, and of which there are already excessive quantities.

Where rainforest and savanna once stood, pastures for cattle-ranching are now appearing. Pastures teem with termites and cattle, whose metabolic activities also release CO₂, although their contribution to atmospheric pollution is under much debate.

With the forests gone, CO₂ is no longer transformed through photosynthesis, and the crops that replace forests only absorb a fraction of CO₂ compared to rainforests. Along with industrial pollution, rampant deforestation in South America and elsewhere has significantly increased the amount of CO₂ in the atmosphere.²

Find out more about the link between 'savannization', carbon dioxide and Amazon rainforests

The importance of the Amazon rainforest for local and global climate

Tropical forests and woodlands (e.g. savannas) exchange vast amounts of water and energy with the atmosphere and are thought to be important in controlling local and regional climates3.

 

Water released by plants into the atmosphere through evapotranspiration (evaporation and plant transpiration) and to the ocean by the rivers, influences world climate and the circulation of ocean currents. This works as a feedback mechanism, as the process also sustains the regional climate on which it depends.

 

Find out about the impacts of climate change on the Amazon  

 

The Amazon rainforest could cure you

What is the connection between the blue-green pills in your bathroom cupboard and the Amazon wildlife? The natural roots of medicine. For millennia, humans have used insects, plants and other organisms in the region for a variety of uses; and that includes agriculture, clothing and, of course, cures for diseases.

 

Indigenous people such as the Yanomamo and other groups of mixed ancestry (e.g. the mestizos of Peru or the caboclos of Brazil) have perfected the use of chemical compounds found in plants and animals4. Knowledge of using these plants is usually held by a medicine man (shaman), who passes on this tradition to an apprentice, a process which has been ongoing for centuries and that forms an integral part of people’s identity.

 

With rainforests going fast, the continuity of this knowledge for the benefit of future generations is under threat.

 

Untapped potential of the Amazon's plants

Scientists believe that less than half of 1% of flowering plant species have been studied in detail for their medicinal potential.5 As the Amazon rainforest biome slowly shrinks in size, so does the richness of wildlife found in its forests, along with the potential use of plants and animals that remain undiscovered.

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¹Laurance, W.F. 1999. Gaia's lungs: Are rainforests inhaling Earth's excess carbon dioxide? Natural History (April), p. 96.
²Post et al, 1990, in Kricher 1997
³Vourlitis, G.L. et al, 2002. Seasonal variations in the evapotranspiration of a transitional tropical forest of Mato Grosso, Brazil. Water Resources Research, Vol. 38
⁴ Phillips et al, 1995, in Kricher 1997
⁵ Cox and Balick, 1994 in Kricher 1997