Quantcast
Environmental News for a Healthier Planet and Life

Scientists Warn We May Be on Track for 'Hothouse Earth'

Climate
Scientists Warn We May Be on Track for 'Hothouse Earth'
iStock / Getty Images

In two recent studies, scientists have looked into the future and into the past to see what might happen to the global climate if we fail to curb greenhouse gas emissions in time. The results are frightening.


A study published Monday in Proceedings of the National Academy of Sciences examined how, once a certain threshold was crossed, feedback loops could push the planet's climate towards a "Hothouse Earth."

The researchers expressed uncertainty as to whether limiting warming to the Paris agreement's upper limit of 2 degrees Celsius above pre-industrial levels would be enough to halt the impacts of climate change, or if feedback loops already in motion would accelerate the process regardless.

"We note that the Earth has never in its history had a quasi-stable state that is around 2C warmer than the preindustrial and suggest that there is substantial risk that the system, itself, will 'want' to continue warming because of all of these other processes—even if we stop emissions," study author Katherine Richardson from the University of Copenhagen told The Guardian.

Some of those other processes include the release of methane from the thawing of the permafrost and the dieback of carbon sinks like the Amazon Rainforest.

When it comes to sea level rise, the scientists outlined how the melting of Greenland's ice could disrupt the Gulf Stream current, lifting sea levels and warming the Southern Ocean, which would in turn melt more ice in Antarctica.

A "Hothouse Earth" would be four degrees warmer than pre-industrial levels, and the path towards reaching it would most likely flood deltas, increase the intensity of coastal storms, and kill off coral reefs by the end of this century or sooner.

Currently, the Earth is around one degree Celsius warmer than pre-industrial levels, and that is already leading to more extreme impacts than would have been predicted, study author and executive director of the Stockholm Resilience Centre Johan Rockström told The Guardian.

"The heatwave we now have in Europe is not something that was expected with just 1C of warming," Rockström said. "Several positive feedback loops are already in operation, but they are still weak. We need studies to show when they might cause a runaway effect."

The paper concluded that to safely avoid a hothouse scenario, humans would have to change their relationship to the Earth.

"Collective human action is required to steer the Earth System away from a potential threshold and stabilize it in a habitable interglacial-like state. Such action entails stewardship of the entire Earth System—biosphere, climate and societies—and could include decarbonization of the global economy, enhancement of biosphere carbon sinks, behavioral changes, technological innovations, new governance arrangements, and transformed social values," the paper said.

Another paper published July 30 in Nature Geoscience looked millions of years into the past to see how hot an Earth with a carbon-dioxide-heavy atmosphere would really be.

The study used peat fossils to assess mid-level temperatures in the early Paleogene, 56 to 48 million years ago.

This was the period after the extinction of the dinosaurs that saw the rise of mammals, as well as atmospheric carbon dioxide levels of 1,000 parts per million, which is what they are predicted to reach by the end of this century if no action is taken, The Atlantic reported.

The study found that during that time, average temperatures in what are now the UK, Germany and New Zealand averaged 23 to 39 degrees Celsius, 10 to 15 degrees warmer than now.

"Europe would look like the Everglades and a heat wave like we're currently experiencing in Europe would be completely normal. That is, it would be the everyday climate," study author and University of Bristol geochemist David Naafs told The Atlantic.

Naafs and his colleagues tried to assess temperatures in the tropics as well, but the ancient lignite samples from India they found turned up temperatures too hot for their method to accurately measure.

"Some climate models suggest that the tropics just became a dead zone with temperatures over 50 degrees Celsius like in Africa and South America," Naafs told The Atlantic. "But we have no data so we don't know."

Google Earth's latest feature allows you to watch the climate change in four dimensions.

Read More Show Less
EcoWatch Daily Newsletter
Researchers say there's a growing epidemic of tap water distrust and disuse in the U.S. Teresa Short / Moment Open / Getty Images

By Asher Rosinger

Imagine seeing a news report about lead contamination in drinking water in a community that looks like yours. It might make you think twice about whether to drink your tap water or serve it to your kids – especially if you also have experienced tap water problems in the past.

Read More Show Less
Trending
A new report urges immediate climate action to control global warming. John W Banagan / Getty Images

A new report promoting urgent climate action in Australia has stirred debate for claiming that global temperatures will rise past 1.5 degrees Celsius in the next decade.

Read More Show Less
Winegrowers check vines during the burning of anti-frost candles in the Luneau-Papin wine vineyard in Le Landreau, near Nantes, western France, on April 12, 2021. SEBASTIEN SALOM-GOMIS / AFP via Getty Images

French winemakers are facing devastating grape loss from the worst frost in decades, preceded by unusually warm temperatures, highlighting the dangers to the sector posed by climate change.

Read More Show Less
A recent study focused on regions in Ethiopia, Africa's largest coffee-producing nation. Edwin Remsberg / Getty Images

Climate change could make it harder to find a good cup of coffee, new research finds. A changing climate might shrink suitable areas for specialty coffee production without adaptation, making coffee taste blander and impacting the livelihoods of small farms in the Global South.

Read More Show Less