Climate change: Tenths count

In the thermometer, a tenth of difference seems something tiny, which is not even noticeable on the street. Small changes in average temperature, however, can have a huge impact on global climate and lead to major disasters. That is the prospect facing the world with increasingly unpredictable, extreme and hot weather.

In 2015, countries around the world agreed in Paris to cut greenhouse gas emissions to contain global warming, bringing it “well below” 2 degrees Celsius (3.6 Fahrenheit). The goal is not to exceed 1.5 degrees (2.7).

Two degrees of difference doesn’t seem like much. When it comes to global average temperatures, however, they make a huge difference.

“Every tenth counts”, meteorologists around the world repeat from time to time.

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EDITOR’S NOTE: This dispatch is part of a series on the most serious problems associated with climate change, the role of science, the impact of global warming and what is being done to deal with this issue.

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The average temperature of the Earth has risen 1.1 degrees Celsius (2 Fahrenheit) since the pre-industrial era. In other words, 0.4 degrees (0.7) more and you will exceed the limit of 1.5 that you do not want to exceed. Once that mark is passed, more climate catastrophes could follow, scientists say.

It is true that tenths count. There is talk of average temperatures, but in some parts of the world, especially in large land masses and in the north, such as the Arctic, temperatures have already risen more than 1.1 degrees and even exceeded 1.5, according to with some estimates.

Try to view temperatures as a bell curve since averaging doesn’t reveal “the hidden extremes,” said Princeton University professor Gabe Vecchi.

“At the extreme, where the shape of the bell is very narrow, there are possibilities for extreme events,” he said. “If there is a slight shift in the average bell top in the direction of warming, the result is that the chances of very cold temperatures are substantially lowered and the chances of much warmer temperatures are increased.”

Something similar happens with the water level. The average rise obscures the fact that in some places the water rose much more than in others.

Most countries, including the top two emitters, the United States and China, are not on track to reduce warming to 1.5. Not even 2 degrees Celsius, according to experts, despite his promises to bring emissions down to “net zero,” when no new emissions are added to the atmosphere.

If temperatures rise more than 2 degrees Celsius by the end of the century, the world will experience five times more floods, storms, droughts and heat waves, according to estimates by the Intergovernmental Panel on Climate Change.

“Anything can happen” in that case, warned Brown University professor Kim Cobb.

The threat of irreversible changes and feedback loops that increase warming, such as melting permafrost, which traps huge amounts of greenhouse gas, can lead to even more warming.

“It’s amazing to think how many people will face an immediate threat from extreme weather events in a two-degree-plus world,” Cobb said.

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The Associated Press’ climate and environment coverage is supported by several private foundations. The HPD is solely responsible for the content.

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