Climate Change Will Affect Tropics First, Long Before Arctic Sees Shift

on October 09 2013 3:48 PM
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The tropics are more vulnerable to climate change than the Arctic, researchers say, because of their relatively stable environments. Air and water temperatures there hardly fluctuate year-round, so any shift in average temperature will surely tip the balance quicker than anywhere else. Flickr/usoceangov

The image of a polar bear drifting away on a chunk of North Pole ice has become synonymous with climate change. But a more accurate archetype for global warming might be an animal with fins and vivid scales. Scientists say the region surrounding Earth’s equator, called the tropics, will feel the effects of global warming long before the poles do.

Unlike the Arctic, where temperatures fluctuate more dramatically year-round, the tropics experience narrower changes in air and ocean temperatures. Any small shift in the environment there will be felt immediately. Species of fish and tropical plants that like their environment consistent won’t respond well to a sudden change in temperature.

That’s according to a team of researchers from the University of Hawaii who wanted to know where and when extreme temperatures, brought on by global warming, would prevail. According to Scientific American, the research team looked at six different variables: Evaporation, heat flux, ocean pH, sea-surface water temperature, precipitation and transpiration. They used information from 39 climate models developed independently by climate scientists from 12 countries to make a timeline of when and where climate change would strike first.

"We are not underestimating the importance of climate change at the poles, we are pointing out the fact that we have been overlooking the potential high impact that will happen at the tropics," Camilo Mora, lead study author and a geographer at the university, said, according to Live Science.

They’ve pinpointed 2047 as the year the mean air temperature around the globe will shift totally out of the range seen in recent history. After 2047, even the coldest year will be warmer than the hottest year over the past 150 years, Live Science reports.

According to an analysis of climate change trends, published Oct.9 in the journal Nature, the first domino to fall will be the tropics, within the next 10 years. One after the other, major cities across the globe will experience “unprecedented” temperature increases exceeding historical extremes. Researchers produced climate change models based on two scenarios: one to reflect no change in global carbon output over the course of the 21st century, and one to reflect a moderate curtailment in CO2 emissions.

Assuming emissions stay consistent, Manokwari, Indonesia, will reach its tipping point in just seven short years. Jakarta will get there by 2029; Mumbia, 2034; New York, 2047; and London, 2056.

"By 2050, between 1 [billion] and 5 billion people, depending on carbon mitigation scenarios, will live in areas undergoing unprecedented climate change," Ryan Longman, a study co-author and graduate student at the University of Hawaii, said. "The countries most impacted are ones with the least ability to respond."

Global carbon emissions hit a record high in 2012. According to the International Energy Agency, or IEA, worldwide CO2 emissions rose by 1.4 percent, to 31.6 billion tons, last year, Reuters reported in June.

Meanwhile, the U.S. was able to curb its emissions by 200 million tons, knocking them back to CO2 levels not seen since the mid-1990s. Japan’s carbon emissions, on the other hand, rose, following the devastating Fukushima nuclear accident in 2011. And any decrease in carbon emissions in the U.S. and Europe was offset by China.

The IEA said the data suggested an average temperature rise of between 3.6 and 5.3 degrees Celsius.

"Global energy-related greenhouse gas emissions in 2020 are projected to be nearly 4 billion tons higher than a level consistent with attaining the 2 degree target, highlighting the scale of the challenge still to be tackled just in this decade," the agency said in June.

The new report from the University of Hawaii isn’t the first to look at our planet’s steady shift towards warmer temperatures. But as The Washington Post notes, by predicting a pattern of exactly when and where hotter temperatures will strike, the study provides a new way to look at global climate change