Quantcast
Popular

Why Half a Degree Really Matters

By Tim Radford

Researchers now know the difference half a degree can make. They can tell you why 1.5°C warming would be better than a 2°C climb in average global temperatures, because even half a degree Celsius could mean greater extremes of heat, more overwhelming rainfall and longer spells of warm weather.


And they know all this because they've seen it happen in the recent past. There is enough evidence, they say, in the observational record for the last half century to underline the importance of even half a degree.

Scientists from Germany and Switzerland outline the argument and identify the evidence in the journal Nature Climate Change.

In the last two centuries, the ratio of carbon dioxide, the result of extravagant fossil fuel use since the Industrial Revolution, has risen from around 280 parts per million to 400 ppm, and average global temperatures have risen around 1°C during that time.

The researchers matched temperature and climate records for the years 1960 to 1979 and 1991 to 2010, a period when the thermometer averages climbed by a whole half a degree.

Significant changes

They found that the intensity of extreme rainfall had increased by nine percent over that period. The coldest winters were measurably less cold, and half of the global land mass had experienced changes of what they called "warm spell duration" of more than six days.

It is not that perceptible global warming made these extremes happen—extremes happen anyway—but the researchers think it made them more likely. By raising the temperature, humans loaded the climate dice.

"The hottest summer temperatures increased by more than 1°C in a quarter of global land areas, while the coldest winter temperatures warmed by more than 2.5°C," said Peter Pfleiderer, a scientist with the Potsdam Institute for Climate Impact Research and for Climate Analytics.

And his colleague Carl-Friedrich Schleussner said, "As we're moving increasingly outside of the range of natural climate variability, we have to expect that impacts on agriculture, human and biological systems will be more pronounced."

The Intergovernmental Panel on Climate Change has begun to prepare a special report on the impacts of a warming of 1.5°C, the Paris agreement target set by the world's nations in 2015.

There is no certainty that the world's nations can meet the Paris target and contain global warming, and limit climate change, because enough carbon dioxide has been emitted to take air temperatures over land to that level already.

The next decade could be critical, which is why researchers feel they need the evidence in as clear a form as possible.

"One of the pressing questions for scientists today is whether we know that limiting warming to 1.5°C instead of 2°C would make a difference in the future. We have to rely on climate models to predict the future, but given we now have observational evidence of around 1˚C warming, we can also look at the real life impacts this warming has brought," Schleussner said.

And the third signatory, Erich Fischer of ETH Zurich, said, "Communicating abstract quantities like differences in global mean temperature is difficult.

"With the warming the world has already experienced, we have an actual record of warming to study, and we can see very clearly that a difference of 0.5˚C of warming really does matter."

Reposted with permission from our media associate Climate News Network.

Show Comments ()

EcoWatch Daily Newsletter

Sponsored
Popular
Kodachrome25 / Getty Images

Roof-to-Garden: How to Irrigate with Rainwater

By Brian Barth

The average American household uses about 320 gallons of water per day, a third for irrigation and other outdoor uses. Collecting the water flowing down your downspouts in rainstorms so you can use it to irrigate in dry periods is often touted as a simple way to cut back. But setting up a functional rainwater irrigation system—beyond the ubiquitous 55-gallon barrels under the downspout, which won't irrigate much more than a flower bed or two—is a fairly complicated DIY project.

Keep reading... Show less
Health
A family wears face masks as they walk through the smoke filled streets after the Thomas wildfire swept through Ventura, California on Dec. 6, 2017. MARK RALSTON / AFP / Getty Images

How to Protect Your Children From Wildfire Smoke

By Cecilia Sierra-Heredia

We're very careful about what our kids eat, but what about the air they breathe?

Keep reading... Show less
Health
Hero Images / Getty Images

Study: Children Have Better Nutrition When They Live Near Forests

Spending time in nature is known to boost mental and emotional health. Now, a new global study has found that children in 27 developing nations tend to have more diverse diets and better nutrition when they live near forests.

The paper, published Wednesday in Science Advances, provides evidence that forest conservation can be an important tool in promoting better nutrition in developing countries, rather than clear-cutting forests for more farmland.

Keep reading... Show less
Health
Navy torpedo bomber spraying DDT just above the trees in Goldendale, WA in 1962. USDA Forest Service

Maternal DDT Exposure Linked to Increased Autism Risk

A study published in the American Journal of Psychiatry Thursday found that mothers exposed to the banned pesticide DDT were nearly one-third more likely to have children who developed autism, Environmental Health News reported.

Keep reading... Show less
Sponsored
GMO
Significant cupping of leaves from dicamba drift on non-Xtend soybeans planted next to Xtend beans in research plots at the Ashland Bottoms farm near Manhattan, KS. Dallas Peterson, K-State Research and Extension / CC BY 2.0

Top Seed Companies Urge EPA to Limit Dicamba

Two of the nation's largest independent seed sellers, Beck's Hybrids and Stine Seed, are urging the U.S. Environmental Protection Agency (EPA) to place limits on the spraying of the drift-prone pesticide dicamba, Reuters reported.

This could potentially hurt Monsanto, which along with DowDupont and BASF SE, makes dicamba formulations to use on Monsanto's Xtend seeds that are genetically engineered to resist applications of the weedkiller. Beck's Hybrids and Stine Seed, as well as other companies, sell those seeds.

Keep reading... Show less
Food
Baby son in high chair feeding father. Getty Images

Baby Food Tests Find 68 Percent Contain 'Worrisome' Levels of Heavy Metals

Testing published by Consumer Reports (CR) Thursday found "concerning levels" of toxic metals in popular U.S. baby and toddler food.

The consumer advocacy group tested 50 nationally-distributed, packaged foods designed for toddlers and babies for mercury, cadmium, arsenic and lead.

Keep reading... Show less
Sponsored
Popular
Interior Secretary Ryan Zinke talks to journalists outside the White House West Wing before attending a Trump cabinet meeting on Aug. 16. Chip Somodevilla / Getty Images

Zinke Announces Plan to Fight Wildfires With More Logging

The Trump administration announced a new plan Thursday to fight ongoing wildfires with more logging, and with no mention of additional funding or climate change.

Keep reading... Show less
Energy
Wangan and Jagalingou cultural leader Adrian Burragubba visits Doongmabulla Springs in Australia. The Wangan and Jagalingou are fighting a proposed coal mine that would likely destroy the springs, which are sacred to the Indigenous Australian group. Wangan and Jagalingou

Indigenous Australians Take Fight Against Giant Coal Mine to the United Nations

By Noni Austin

For tens of thousands of years, the Wangan and Jagalingou people have lived in the flat arid lands of central Queensland, Australia. But now they are fighting for their very existence. Earlier this month, they took their fight to the United Nations after years of Australia's failure to protect their fundamental human rights.

Keep reading... Show less
Sponsored

mail-copy

The best of EcoWatch, right in your inbox. Sign up for our email newsletter!