Rising temperatures linked to global warming are not just a sign of climate change but are a cause of it, a study shows.
Higher temperatures on the surface of the earth are themselves fuelling a further increase in emissions of methane, a greenhouse gas with a significant role in global warming.
Scientists studied atmospheric levels of methane from the world’s largest source of the gas, wetlands such as paddy fields, marshes and bogs.
They found that emissions are increasing in line with rising temperatures.
The postgraduate study, published in Science, indicates that warmer temperatures in high latitude regions increase the production of methane.
This in turn exacerbates global warming.
Researchers used satellite measurements of the atmospheric concentration of methane as well as data relating to surface temperature changes and variations in surface water.
This enabled them to work out the levels of wetland emissions of methane from different regions.
The results indicate that output from wetlands increased 7 per cent from 2003-2007.
The findings also show which regional wetland emissions are most sensitive to changes in flooding and extreme temperatures. This will help scientists predict future climate change.
The study was funded by the Natural Environment Research Council and carried out in collaboration with the Netherlands Institute for Space research.
Data was supplied by Nasa and the European Space Agency.
These findings highlight the compound effect of increasing global warming – higher temperatures lead to faster warming. Our study reinforces the idea that satellites can pinpoint changes in the amount of greenhouse gases emitted from a particular place on earth. This opens the door to quantifying greenhouse gas emissions made from a variety of natural and man-made sources.