Quantcast

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

Climate
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."

Related Articles Around the Web
From Your Site Articles

    EcoWatch Daily Newsletter

    Pexels

    By Ketura Persellin

    Global consumption of beef, lamb and goat is expected to rise by almost 90 percent between 2010 and 2050. But that doesn't mean you need to eat more meat. In fact, recent news from Washington gives you even less confidence in your meat: Pork inspections may be taken over by the industry itself, if a Trump administration proposal goes into effect, putting tests for deadly pathogens into the hands of line workers.

    Read More Show Less
    Pexels

    By Kaitlyn Berkheiser

    While enjoying an occasional alcoholic beverage is unlikely to harm your health, drinking in excess can have substantial negative effects on your body and well-being.

    Read More Show Less
    Sponsored
    MStudioImages / E+ / Getty Images

    By Jillian Kubala, MS, RD

    Backpacking is an exciting way to explore the wilderness or travel to foreign countries on a budget.

    Read More Show Less
    Tim P. Whitby / 21st Century Fox / Getty Images

    The beauty products we put on our skin can have important consequences for our health. Just this March, the U.S. Food and Drug Administration (FDA) warned that some Claire's cosmetics had tested positive for asbestos. But the FDA could only issue a warning, not a recall, because current law does not empower the agency to do so.

    Michelle Pfeiffer wants to change that.

    The actress and Environmental Working Group (EWG) board member was spotted on Capitol Hill Thursday lobbying lawmakers on behalf of a bill that would increase oversight of the cosmetics industry, The Washington Post reported.

    Read More Show Less
    A protest march against the Line 3 pipeline in St. Paul, Minnesota on May 18, 2018. Fibonacci Blue / CC BY 2.0

    By Collin Rees

    We know that people power can stop dangerous fossil fuel projects like the proposed Line 3 tar sands oil pipeline in Minnesota, because we've proved it over and over again — and recently we've had two more big wins.

    Read More Show Less
    Sponsored
    Scientists released a study showing that a million species are at risk for extinction, but it was largely ignored by the corporate news media. Danny Perez Photography / Flickr / CC

    By Julia Conley

    Scientists at the United Nations' intergovernmental body focusing on biodiversity sounded alarms earlier this month with its report on the looming potential extinction of one million species — but few heard their calls, according to a German newspaper report.

    Read More Show Less
    DoneGood

    By Cullen Schwarz

    Ethical shopping is a somewhat new phenomenon. We're far more familiar with the "tried and tested" methods of doing good, like donating our money or time.

    Read More Show Less
    Pixabay

    Summer is fast approaching, which means it's time to stock up on sunscreen to ward off the harmful effects of sun exposure. Not all sunscreens are created equally, however.

    Read More Show Less