Quantcast
Environmental News for a Healthier Planet and Life

Help Support EcoWatch

Scientists Share Why Keeping Warming Under 1.5 Degrees Celsius Is Crucial

Climate
Scientists Share Why Keeping Warming Under 1.5 Degrees Celsius Is Crucial

With the possible prospect of the world warming dangerously and uncontrollably, half of one degree Celsius may sound like a negligible temperature change unlikely to make much difference to life on Earth.

But scientists say 0.5 C could make a crucial difference in some regions—particularly in developing countries in the tropics—that are already at great risk from climate change. The consequences could include higher sea level rise and extended heatwaves, threatening most tropical coral reefs.

Bill Hare, CEO of Climate Analytics and a member of the research team that has produced the cautionary report, said: “Our study shows that tropical regions—mostly developing countries that are already highly vulnerable to climate change—face the biggest rise in impacts between 1.5 C and 2 C.

Vulnerable Countries

“Our results add to a growing body of evidence showing that climate risks occur at lower levels than previously thought. They provide scientific evidence to support the call by vulnerable countries, such as the Least Developed Countries and Small Island Developing States, that a 1.5 C warming limit would substantially reduce the impacts of climate change.”

The Paris agreement on climate change being signed today in New York was concluded at last December’s UN climate conference. It aims to keep global average temperatures “well below” the 2 C previously agreed—and to pursue efforts to limit the increase to 1.5 C.

But the report by European researchers—published in Earth System Dynamics, an open access journal of the European Geosciences Union (EGU)—says they have found that there would be substantially different impacts for the two targets by 2100. They say the extra 0.5 C would mean a global sea-level rise of 10 centimeters, longer heatwaves and would put virtually all tropical coral reefs at risk.

“We found significant differences for all the impacts we considered,” said the study’s lead author, Carl-Friedrich Schleussner, a physicist at Climate Analytics.

“We analyzed the climate models used in the Intergovernmental Panel on Climate Change’s Fifth Assessment Report, focusing on the projected impacts at 1.5 C and 2 C warming at the regional level. We considered 11 different indicators, including extreme weather events, water availability, crop yields, coral reef degradation and sea-level rise.”

The team, including researchers from Germany, Switzerland, Austria and the Netherlands, identified a number of hotspots around the globe where projected climate impacts at 2 C are significantly more severe than at 1.5 C.

One of these is the Mediterranean region, already experiencing climate change-induced drying. With a global temperature increase of 1.5 C, the availability of fresh water in the region would be about 10 percent lower than in the late 20th century. But in a 2 C world, the researchers project that this reduction would double to about 20 percent.

In tropical regions, the half-a-degree difference in global temperature could damage crop yields, particularly in Central America and West Africa. On average, local tropical maize and wheat yields would fall twice as much with a 2 C temperature increase as with 1.5 C.

By 2100, tropical regions would also experience warm spells lasting up to 50 percent longer in a 2 C world than at 1.5 C. “For heat-related extremes, the additional 0.5 C increase marks the difference between events at the upper limit of present-day natural variability and a new climate regime, particularly in tropical regions,” Schleussner said.

The extra warming would also affect tropical coral reefs. Limiting warming to 1.5 C would provide a window of opportunity for some reefs to adapt to climate change, but a 2 C increase by 2100 would put virtually all of them at risk of severe degradation from coral bleaching.

Large-scale Bleaching

Australian researchers say 93 percent of the Great Barrier Reef, off the coast of Queensland, is affected to some degree by bleaching. They say large-scale bleaching has also been found off Australia’s west coast.

In the EGU study, the researchers say they expect sea level to rise by about 50 cm by 2100 in a 2 C warmer world, 10 cm more than for 1.5 C warming. These levels are appreciably lower than some scientists expect.

“Sea level rise will slow down during the 21st century only under a 1.5 C scenario,” Dr. Schleussner warns.

One of his co-authors, Jacob Schewe, a climate physicist at the Potsdam Institute for Climate Impact Research, Germany, says it is necessary to account for natural variability, model uncertainties and other factors that could obscure the picture.

“We did that in our study,” he said. “And by focusing on key indicators at the regional level, we clearly show that there are significant differences in impacts between 1.5 C and 2 C.”

YOU MIGHT ALSO LIKE

Scientists Confirm: 93% of Great Barrier Reef Now Bleached

Not Everyone Is Celebrating the Signing of the Paris Climate Agreement

Do the Koch Brothers Want to Mine the Grand Canyon for Uranium?

NOAA: Last Month Was by Far the Planet’s Warmest March Since Record Keeping Began

Could mouthwash help stop the spread of the new coronavirus? Craig F. Walker / The Boston Globe via Getty Images

Could mouthwash help stop the spread of the new coronavirus?

Read More Show Less

EcoWatch Daily Newsletter

This turtle dove is part of Operation Turtle Dove; the European Commission estimates there may be fewer than 5,000 pairs left in the UK. Ian / Flickr / CC by 2.0

By Naomi Larsson

For centuries, the delicate silver dove has been a symbol of love and fidelity.

Read More Show Less

Trending

We pet owners know how much you love your pooch. It's your best friend. It gives you pure happiness and comfort when you're together. But there are times that dogs can be very challenging, especially if they are suffering from a certain ailment. As a dog owner, all you want to do is ease whatever pain or discomfort your best friend is feeling.

Read More Show Less
Swimming alongside an animatronic dolphin, a person learns about hydrodynamics. Edge Innovations

Life-sized, ultra-realistic robotic dolphins could help end animal captivity by replacing living creatures in aquariums and theme parks.

Read More Show Less
A Stop the Money Pipeline protester holds a banner outside JP Morgan headquarters in NYC on Feb. 25, 2020; JP Morgan is a top contributor to the fossil fuel industry. Erik McGregor / LightRocket / Getty Images

By Jessica Corbett

Green groups applauded Sen. Jeff Merkley on Wednesday for introducing a pioneering pair of bills that aim to "protect the long-term health and well-being of the American people and their economy from the catastrophic effects of climate chaos" by preventing banks and international financial institutions from financing fossil fuels.

Read More Show Less

Support Ecowatch