As carbon dioxide levels in the atmosphere steadily rise, Nasa is warning that the capacity of Earth's oceans, forests and land ecosystems to absorb human-generated carbon dioxide could one day dramatically weaken.

Currently, the planet 'breathes' - forests, rainforests and oceans all absorb carbon dioxide, taking up about half of all human-emitted carbon.

However, carbon levels are rising - there's currently around 400 parts per million (ppm) or carbon dioxide in the atmosphere, a figure which is rising by 2ppm every year.

As this number gets higher, the less we can rely on the natural world to take care of the bulk of our emissions.

December will see world leaders meet at a United Nations climate conference in Paris, which could prove vital to lessening the worst effects of climate change in the future.

To help the leaders make decisions, Nasa has released detailed measurements and simulations of the world's sources of carbon dioxide, and how it moves through the atmosphere.

One simulation, created with measurements recorded by the Orbiting Carbon Observatory-2 satellite and modelled by the Goddard Earth Observing Model 5 inside a supercomputer, shows where the carbon is coming from.

Focusing on two main carbon sources, burning biomass and cities, the animation shows global hotspots for carbon emissions.

As shown by the red and white hotspots over central Africa, there's a huge amount of biomass being burned, indicating possible forest fires.

The blue clouds show carbon emitted from cities - much of East Asia, in China and Japan, is entirely blue, indicating huge levels of emissions put out by densely populated urban centres.

Blue hotspots also form along the densely-populated American coasts, and in western Europe - the two clouds eventually drift together across the northern hemisphere, leaving a purple carbon cloud.

These kinds of simulations will present Paris delegates with detailed information on where the world's carbon is coming from - if they want to take action, they will need to target the major sources, while the planet is still absorbing much of our emissions.

As Nasa atmospheric scientists Lesley Ott says: "The land and the ocean are really doing us a big favour."