Finally tonight, hundreds of miles from the UN Conference on Climate Change that wrapped up this weekend in BM, Brazil, there's a firstofits-kind experiment that could help future policy makers address the issue.

Here's John Yang.

In the Amazon jungle, steel towers peak over the tops of mature trees.

Scientists call it a time machine, giving them a glimpse into the future.

Carlos Alberto Casada is coordinator at Brazil's National Institute of Amazonian Research.

From these towers, we will release CO2 into the treetops and try to create the atmosphere of the future there in that environment.

Then we can study all the ecological processes that will be altered with more carbon in the system.

It's part of a groundbreaking program called Amazon FACE Free Air CO2 Enrichment.

The idea is to pump CO2 into the tree canopies to replicate rising greenhouse gas emissions.

Researchers use cranes to collect data about water use, leaf resistance, and other indications of the treere's health.

They hope these readings will provide an insight into the Amazon's ability to adapt to climate change.

With these sensors, we can get the forest response every 10 minutes.

For example, if it rains, if it's sunny, if there's a storm, we know how the forest works.

Amazon's rainforest is sometimes called the lungs of the earth, absorbing billions of tons of carbon dioxide every year and releasing oxygen.

Its health is directly tied to the planets.

It affects rainfall worldwide and the overall balance of the Earth's water system.

Researchers hope the data this experiment yields will help global policy makers better navigate climate change.

How much CO2 can we still admit within a twoderee temperature increase?

We will be able to understand what trajectories the Amazon will take and prepare decades in advance.