The Decade of "Climate Departure"

 

Several years ago the climate department at the University of Hawaii released a paper warning of a phenomenon they called "climate departure" that would begin to set in during the first half of this decade.

“The coldest year in the future will be warmer than the hottest year in the past,” said Camilo Mora, the lead scientist on a paper published in the journal Nature.

Unprecedented climates will arrive even sooner in the tropics, Dr. Mora’s group predicts, putting increasing stress on human societies there, on the coral reefs that supply millions of people with fish, and on the world’s greatest forests.

“Go back in your life to think about the hottest, most traumatic event you have experienced,” Dr. Mora said in an interview. “What we’re saying is that very soon, that event is going to become the norm.” 

Climate departure not only means hotter years. It also means there'll be no more cold years as we've experienced them in the past.  Once a region enters 'departure' every year afterward will be hotter than the hottest year pre-departure.

There are already signs that departure is taking hold in tropical regions.  A new study finds that deforestation, common to the tropics, is making outdoor working dangerous, nearly impossible. For countries where much of the population relies on subsistence agriculture the change is catastrophic.

“Because of climate change, these areas in the tropics are already on the edge of what’s considered safe or comfortable for working in the late morning to afternoon,” said Luke Parsons, a climate researcher at Duke University in North Carolina and lead author of the paper published in the journal One Earth. “And then you take deforestation on top of that and it pushes these regions over into even more unsafe work conditions.”

A growing body of research has shown that deforestation is linked to an increase in local temperatures, as it decreases the cooling benefits trees bring to an area. For example, in the areas of the Amazon in Brazil which have been heavily deforested, over the past two decades the temperatures have been as much as 10C higher than forested regions.

For this study, the researchers parsed satellite and meteorological data between 2003 and 2018 in 94 countries with tropical forests, looking at temperature and humidity.

For people living on the margins of poverty becoming unable to work outside for a few hours or half a day every day can be an insurmountable challenge.