Quantcast
Climate
Researchers warn that unchecked fossil fuel emissions would raise global temperatures to catastrophic levels. Gerry Machen / Flickr

New Study: Global Warming Limit Can Still Be Achieved

By Tim Radford

Scientists in the UK have good news for the 195 nations that pledged to limit global warming to well below 2°C: it can be done. The ideal limit of no more than 1.5°C above the average temperatures for most of human history is possible.

All it requires is an immediate reduction in the combustion of fossil fuels—a reduction that will continue for the next 40 years, until the world is driven only by renewable energy.


This optimistic assessment is possible because of new information, coupled with another look at the challenge ahead, according to scientists from Exeter, London, Leeds and Oxford, backed up by colleagues from Norway, Austria, Switzerland, Canada and New Zealand.

They reported in Nature Geoscience journal that they have a new estimate for the mass of fossil fuels it would be safe to burn, consistent with achieving the target agreed at the Paris climate conference in 2015.

Pre-industrial levels

Industry has a bit more room to maneuver as it adjusts, and researchers now have a more up-to-date estimate of how much extra carbon dioxide may be released into the atmosphere before the global thermometer starts to reach potentially dangerous temperatures.

"Limiting total CO2 emissions from the start of 2015 to beneath 240 billion tonnes of carbon—880 billion tonnes of CO2–or about 20 years of current emissions would likely achieve the Paris goal of limiting warming to 1.5°C above pre-industrial levels," said study leader Richard Millar, a climate system scientist at the University of Oxford.

And his colleague, Pierre Friedlingstein, the University of Exeter's chair in mathematical modelling of climate systems, who advises the Intergovernmental Panel on Climate Change (IPCC) on carbon budgets, said, "Previous estimates of the remaining 1.5°C carbon budget based on the IPCC Fifth Assessment were around four times lower, so this is very good news for the achievability of the Paris targets."

The problem can be put simply—even if the solution remains a global headache. For 200 years, humans have been exploiting coal, oil and natural gas on a massive scale, destroying forests and converting wilderness to crops and pasture.

To burn fossil fuel is to release a greenhouse gas into the atmosphere—and the more carbon dioxide in the atmosphere, the warmer the world. What had once been a stable ratio of around 280 parts per million of carbon dioxide has crept up to around 400 ppm in 2016, and global average temperatures are about 0.9°C higher than the pre-industrial average.

The big question is how much more carbon dioxide can the factories, power stations and car exhausts of the world emit before the temperature goes up another 0.6°C, but no higher?

Almost as soon as the world's nations settled on the Paris target, there were doubts about whether the temperature limit is achievable, and these doubts have been expressed by distinguished scientists at the forefront of climate change research.

The latest study indicates that it can be done. But parallel research published in Nature Geoscience suggests there is no time to lose.

Norwegian scientists reported that the global greenhouse effect caused by human increases in carbon dioxide concentrations is now halfway to doubling. That is not the same as twice the levels of carbon dioxide in the atmosphere: what is being measured here is the extra heat that double the carbon dioxide will guarantee.

'Dangerous' global warming

"The doubling of CO2 now has an iconic role in climate research," the Norwegian report said. "In terms of radiative forcing, we are still likely to have come more than halfway to a doubling of CO2 in the atmosphere."

And a third study, published in the Proceedings of the National Academy of Sciences, spells out the importance of the Paris agreement when it comes to global risk.

Researchers in Texas and California said the "well below 2°C target" set in Paris commits the world to "dangerous" global warming, and a rise of 3°C on average for the whole globe would rate as "catastrophic."

But a rise of 5°C would, the researchers say, deliver risks that are "unknown, implying beyond catastrophic." And if emissions are not checked, the world will reach the dangerous level in three decades.

So the overall message is that a 1.5°C limit is possible, but the world had better start working towards that goal now.

"The sooner global emissions start to fall, the lower the risk not only of major climate disruption, but also of economic disruption that could otherwise arise from the need for subsequent reductions at historically unprecedented rates, should near-term action remain inadequate," said another of the report's authors, Michael Grubb, professor of international energy and climate change policy at University College London's Institute of Sustainable Resources.

Reposted with permission from our media associate Climate News Network.

Show Comments ()
Sponsored
Shutterstock

September 2017: Earth's 4th Warmest September on Record

By Dr. Jeff Masters

September 2017 was the planet's fourth warmest September since record keeping began in 1880, said the National Oceanic and Atmospheric Administration's (NOAA) National Centers for Environmental Information (NCEI) and NASA this week. The only warmer Septembers came during 2015, 2016 and 2014. Minor differences can occur between the NASA and NOAA rankings because of their different techniques for analyzing data-sparse regions such as the Arctic.

Keep reading... Show less

Shocking Photo of Dehorned Black Rhino Wins Top Award

Africa loses an average of three rhinos a day to the ongoing poaching crisis and the illegal rhino horn trade. In 2016 alone, 1,054 rhinos were reported killed in South Africa, representing a loss in rhinos of approximately six percent. That's close to the birth rate, meaning the population remains perilously close to the tipping point.

This year, the Natural History Museum in London awarded photographer Brent Stirton the 2017 Wildlife Photographer of the Year grand title for his grisly image of a black rhino with its two horns hacked off in South Africa's Hluhluwe-Imfolozi Park.

Keep reading... Show less
Popular
Smallholder agriculture in southern Ethiopia. Smallholder farmers are particularly vulnerable to food insecurity. Leah Samberg

How Climate Change and Wars Are Increasing World Hunger

By Leah Samberg

Around the globe, about 815 million people—11 percent of the world's population—went hungry in 2016, according to the latest data from the United Nations. This was the first increase in more than 15 years.

Between 1990 and 2015, due largely to a set of sweeping initiatives by the global community, the proportion of undernourished people in the world was cut in half. In 2015, UN member countries adopted the Sustainable Development Goals, which doubled down on this success by setting out to end hunger entirely by 2030. But a recent UN report shows that, after years of decline, hunger is on the rise again.

Keep reading... Show less
Pixabay

Two Graphs Explain Why California’s Wildfires Will Only Get Worse

By Molly Taft

The deadly wildfires ripping through Northern California are just the latest in a season of record-defying natural disasters in the U.S. As the death toll passes 40, reports of Californians hiding in pools as their houses burn and scenes of devastated homes and vineyards add to 2017's apocalyptic picture of how climate change is impacting America today.

As the Trump administration guts environmental protections and undermines science, California is one of the states leading the way on climate action. Ironically, experts agree the state can expect devastating fires like the ones in Napa to become the new normal. Drier and drier conditions and creeping temperatures in the American Southwest, definitively linked to climate change, serve to create tinderbox conditions for massive, catastrophic fires to explode.

Keep reading... Show less
Sponsored
Leonardo DiCaprio / Facebook

Leonardo DiCaprio Invests in Plant-Based Food Company

Animal agriculture is responsible for more greenhouse gas emissions than the entire transportation sector, but eating a burger doesn't have to come with a side of guilt.

Actor and environmentalist Leonardo DiCaprio has invested in Beyond Meat, the makers of the world's first vegan burger that's famously known to look, smell and even taste a lot like the real deal.

Keep reading... Show less
www.facebook.com

Guard Dog Wouldn’t Leave Goat Flock During California Fires—And Lived to Tell the Story

By Andrew Amelinckx

The fire the Hendels barely escaped was part of the Northern California firestorm that has so far claimed 40 lives—including one of their neighbors, Lynne Powell—destroyed countless homes, and caused billions of dollars in damage.

"Later that morning when we had outrun the fires I cried, sure that I had sentenced Odie to death, along with our precious family of bottle-raised goats," Roland Hendel wrote in a recent Facebook post.

Keep reading... Show less
Sponsored
Climate activists Emily Johnston and Annette Klapstein shut down Enbridge's tar sands pipelines 4 and 67 in Minnesota on Oct. 11, 2016. Shutitdown.today

Judge Allows Vital 'Necessity Defense' for Climate Activists

By Jessica Corbett

In a decision that is being called "groundbreaking" and "precedent-setting," a district court judge in Minnesota has ruled that he will allow oil pipeline protesters to present a "necessity defense" for charges related to a multi-state action by climate activists last October.

In his decision last week, Judge Robert Tiffany ruled that four activists who participated in the #ShutItDown action—in which pipelines across five states were temporarily disabled, halting the flow of tar sands oil from Canada into the U.S.—may present scientists and other expert witnesses to explain the immediate threat of climate change to justify their action.

Keep reading... Show less
www.youtube.com

Why Are Incarcerated Women Battling California Wildfires for as Little as $1 a Day?

As raging wildfires in California scorch more than 200,000 acres—roughly the size of New York City—more than 11,000 firefighters are battling the blazes, and a number of them are prisoners, including many women inmates.

Keep reading... Show less
Sponsored

mail-copy

Get EcoWatch in your inbox