Rising humidity can worsen impact of higher temperatures - study

MUMBAI (Thomson Reuters Foundation) - High humidity will magnify the effects of rising heat from South America to India, affecting people’s ability to work and even survive, unless greenhouse gas emissions are substantially cut in coming decades, according to U.S. researchers.

Heat remains underestimated as a threat by governments, aid agencies and individuals, and muggy heat is even more oppressive than the “dry” kind, because it stops people from sweating which takes away excess heat.

A study from the Earth Institute at Columbia University found areas along the coast and others that experience humid-weather patterns will be most affected by higher temperatures unless governments curb greenhouse gas emissions that can raise temperatures and put in place measures to tackle the heat.

The areas likely to be affected include the Amazon, southeastern United States, western and central Africa, parts of the Middle East, northern India and eastern China.

Current and projected “wet bulb” temperatures - which reflect the combined effects of heat and humidity - found that by the 2070s, high wet-bulb readings that now occur maybe once a year could prevail 100-250 days of the year in some parts.

“The conditions we’re talking about basically never occur now - people in most places have never experienced them,” said lead author Ethan Coffel at Columbia’s Lamont-Doherty Earth Observatory.

“Failure to adopt both mitigation and adaptation measures is likely to result in suffering, economic damage, and increased heat-related mortality.”

Rising temperatures may make low-latitude developing nations in the Asian subcontinent, the Middle East, Africa and South America practically uninhabitable during the summer months, another report earlier this year noted.

With muggy heat, the air is already heavy with moisture, so sweat stops evaporating, halting a process to cool the body. If there is no air conditioning, organs strain and can start to fail.

This can lead to lethargy, sickness and, in the worst conditions, death, according to the new study.

The study projects parts of the Middle East and northern India may hit 35 wet-bulb degrees Celsius by late century - equal to the skin’s temperature, and the theoretical limit at which people will die within hours without artificial cooling.

“It’s not just about the heat ... it’s about how many people are poor, how many are old, who has to go outside to work, who has air conditioning,” said Alex de Sherbinin at Columbia’s Center for International Earth Science Information Network. 

Global temperature to rise next year but no new record 

LONDON (Reuters) - The global average temperature will rise again next year but is unlikely to set a new record due to the cooling effect from the La Nina weather phenomenon in the Pacific, Britain’s Met Office said.

The global average temperature rise for 2018 is forecast to be between 0.88 and 1.12 degrees Celsius above the pre-industrial average period 1850–1900.

This corresponds to an increase of between 0.28 and 0.52 degrees C above a 1981–2010 long-term average of 14.3 degrees C.

“2018 will be very warm globally but is unlikely to exceed the recent record, set in 2016,” Adam Scaife, head of long-range prediction at Britain’s Met Office, said in a statement.

Last month, the U.N.’s World Meteorological Office (WMO) said this year will be among the three hottest on record, slightly less warm than a record 2016 and roughly on a level with 2015.

“For 2018, the global temperature will remain high, but the current La Niña conditions suggest that average temperatures will be around 0.1 degree lower than we would otherwise expect in 2018,” Met Office research fellow Doug Smith said.

La Nina is a weather phenomenon characterised by unusually cold ocean temperatures in the equatorial Pacific Ocean, linked to floods and droughts.

Last week, a U.S. government weather forecaster said La Nina conditions were likely to continue through the Northern Hemisphere during the winter of 2017-18.

The Met Office said 16 of the 17 warmest years on record have occurred since the year 2000.

Its forecast for next year is based on global climate drivers but does not include unpredictable incidents such as a large volcanic eruption which would cause a temporary cooling, the Met Office said.