The world is indeed getting warmer - but not everywhere and not at the same rate, the first detailed study on global land surface warming trends over the last 100 years has found.
New research by Florida State University scientists, illustrating precisely when and where different areas of the world started to warm up or cool down, indicates that the planet is indeed getting warmer.
However, historical records show that the warming has not happened everywhere at the same rate, researchers said.
"Global warming was not as understood as we thought," said Zhaohua Wu, an assistant professor of meteorology at FSU.
The team, using an analysis method newly developed by Wu and his colleagues, examined land surface temperature trends from 1900 onward for the entire globe, minus Antarctica.
Previous work by scientists on global warming could not provide information of non-uniform warming in space and time due to limitations of previous analysis methods in climate research.
The research team found that noticeable warming first started around the regions circling the Arctic and subtropical regions in both hemispheres.
But the largest accumulated warming to date is actually at the northern mid-latitudes. They also found that in some areas of the world, cooling had actually occurred.
"The global warming is not uniform. You have areas that have cooled and areas that have warmed," Eric Chassignet, director of Center for Ocean-Atmospheric Prediction Studies (COAPS) said.
For example, from about 1910 to 1980, while the rest of the world was warming up, some areas south of the equator - near the Andes - were actually cooling down, and then had no change at all until the mid 1990s.
Other areas near and south of the equator didn't see significant changes comparable to the rest of the world at all, researchers said.
The study was published in the journal Nature Climate Change.
