Rainforests and climate

Rainforests help to regulate Earth's climate

Forests in tropical and temperate regions have a cooling effect, whereas boreal forests found in high northern latitudes have a warming effect. This helps to regulate temperature extremes.

All forests play an important role in the water cycle, by transporting a huge amount of water from the soil to the sky, creating clouds and rain. Water is released from the leaves as vapour into the atmosphere in a process called transpiration. In rainforests, this process is turbocharged. There is more water in the sky above the Amazon rainforest than in the mighty River Amazon below.

Green rainforest canopy with white clouds above

How?

Rainforests are:

Air movers: Rainforests make rain and rain makes rainforests
Sun reflectors: Massive white clouds form above rainforests which reflect sunlight
Rain makers: Rainforests make rain and rain makes rainforests
Water transporters: Water is drawn up through narrow vessels inside the tree. It then evaporates into the sky through tiny holes in leaves. This cools the air and creates clouds.
Carbon catchers: Forests take in CO₂ from the air as they grow. It’s stored as solid carbon compounds in their roots, wood, leaves, seeds and flowers.
Flood defenders: Rainforest roots and soil hold onto water like a sponge, which slows run-off.

You can learn more about all of this by visiting the exhibits on the Rainforest Canopy Walkway in our Rainforest Biome.

Dark skies and lightning above a field with fence

How is climate change affecting the rainforests?

CO₂ levels are rising: they’re the highest they’ve been for 4 million years
As CO₂ rises so does the temperature. The Earth has already warmed by an average of 1.1°C since the Industrial Revolution. Every 0.1°C of warming is enough to disrupt weather patterns and increase the risk of severe storms, heatwaves and wildfires.
The globally agreed Paris Agreement aims to limit warming to below 2°C and to bring it below 1.5°C by 2100. Currently, we’re on a trajectory that would take us to between 2.3 and 2.8°C of warming.

In rainforests this is already taking effect in the form of severe droughts, more forest fires and an increase in lightning strikes. Recent data also suggests that in some tropical regions, deforestation can lead to temperature increases of up to 5°C.

Tree-climber scientist high in rainforest tree

Rainforest research

Eden is working with scientists from the University of Exeter and the Met Office to bring you the latest
research on rainforests and the climate.

They’re investigating the effects of climate change, increased CO₂ and drought on tropical rainforests, and modelling how continual rainforest loss of will further impact the Earth’s climate.

Exhibit signage in Eden Project Rain Shack

Climate change and the water cycle

A large rainforest tree can transport thousands of litres of water from soil to sky every day, creating clouds and rain that help regulate the global water cycle.

Some trees grow up to 100 metres tall – as high as a 30-storey building. That’s a long way for water to travel uphill!

The warming climate is putting extra pressure on the largest rainforest trees.

Too warm, and the trees' water transport systems will fail, and the tree will die. This will impact the global water cycle, devastate rainforest ecosystems, and make climate change worse - as the carbon stored in the trees will be released as CO₂ into the atmosphere.

These trees must be protected. This research is helping direct conservation work to where it’s most needed.

To learn more, visit the Rain Shack in our Rainforest Biome.