Global warming hits poorest hardest

The new study, published today in Geophysical Research Letters, a journal of the American Geophysical Union, compares the difference between climate change impacts for wealthy and poor nations.

"The results are a stark example of the inequalities that come with global warming," said lead author Andrew King from the ARC Centre of Excellence for Climate Extremes at the University of Melbourne in Australia.

"The richest countries that produced the most emissions are the least affected by heat when average temperatures climb to just 2°C, while poorer nations bear the brunt of changing local climates and the consequences that come with them."

The least affected countries include most temperate nations, with the United Kingdom coming out ahead of all others. By contrast, the worst affected are in the Equatorial regions, including countries like the Democratic Republic of Congo.

This pattern holds true even if global average surface temperatures only reach 1.5°C above pre-industrial levels.

To get their results the researchers used a simple metric -- the signal to noise ratio. The signal in this case is the local change in average temperatures caused by climate change. The noise is how variable the temperature is for that region.

In places outside the tropics, where there is greater year-to-year variability and those locations are more well adapted to a wide range of temperatures, the warming will be less noticeable.

But in Equatorial regions, where there is already a very high average temperature and less variation through the year, a small rise in temperatures due to climate change will be distinctly felt and have immediate impacts.

This difference in experienced temperature combined with the distribution of wealth across the world, with richer nations tending to be in temperate regions and the poorer nations in the tropics, adds to the future climate change burden of developing nations.

"Economically powerful nations, who are most responsible for the emissions that led to global warming, are going to have to pick up the slack if they want to maintain economic growth in developing countries," said co-author Luke Harrington from the University of Oxford.

"It's why we need to invest in limiting the worst impacts of climate change for developing nations today. By assisting developing nations to meet these challenges we help maintain their economic stability and security into the future and by extension, our own as well."