Published: Tue, August 07, 2018
Research | By Raquel Erickson

Climate Change: What A "Hothouse" Earth Would Really Look Like

Climate Change: What A

The planet at risk of entering an irreversible "hothouse" climate, scientists say.

Scientists from the Stockholm Resilience Center, the University of Copenhagen, Australian National University and the Potsdam Institute for Climate Impact Research worked on the study.

A new worldwide study has found that the world could face a "hothouse" climate where efforts to reduce emissions will have no impact if the Earth's global average temperature increases by a further 1 degree Celsius.

"It would be a planet where large parts of the Arab regions would be inhabitable".

The study warns that Earth is already more than halfway towards the point of no return.

Global average temperatures are just over one degree Celsius above pre-industrial temperatures and rising at 0.17 degrees Celsius each decade.

With Arctic ice and glaciers melting away; increasingly powerful and frequent storms in the Atlantic and Pacific; coral reefs dying from warming oceans; record-setting wildfires in the USA; unprecedented heatwaves in Europe, the Middle East, and elsewhere-climate researchers have been at the forefront of sounding the alarms about the frightening path humanity is now following.

Avoiding a Hothouse Earth would require "deep cuts" in greenhouse gas emissions as well as concerted efforts to remove carbon dioxide from the atmosphere, the researchers said.

"Where such a threshold might be is uncertain, but it could be only decades ahead at a temperature rise of (around) 2C above pre-industrial".

Sea levels could also rise between 10 and 60 metres, threatening coastal areas.

"Hothouse Earth is likely to be uncontrollable and risky to many", said the article by scientists at University of Copenhagen, Australian National University and the Potsdam Institute for Climate Impact Research in Germany.

"If we go past two degrees, then we risk triggering a cascade of these tipping points that could push us all the way to the hothouse earth..."

In the long-term, the Hothouse Earth climate will stabilise at a global average of 4C - 5C above pre-industrial levels, the study shows.

"The impacts of a Hothouse Earth pathway on human societies would likely be massive, sometimes abrupt, and undoubtedly disruptive", says the study, which is published in the journal Proceedings of the National Academy of Sciences of the United States of America.

The tipping point dangers were identified as thawing permafrost, the release of methane trapped on the ocean floor, weakening land and ocean carbon sinks, increased carbon dioxide production by ocean bacteria, Amazon rainforest die-back, coniferous forest die-back, reduced northern hemisphere snow cover, loss of Arctic summer sea ice, reduced Antarctic sea ice and melting polar ice sheets.

Feedback mechanisms would act "like a row of dominoes", spinning the world into a state of climate change that will alter the landscape of the planet.

"Once one is pushed over, it pushes earth towards another".

Rockström added that stopping the "whole row of dominoes from tumbling over" will be either hard, or impossible, and that "if Hothouse Earth becomes the reality", some places on Earth will be uninhabitable.

Rivers would flood, storms would wreak havoc on coastal communities, and coral reefs would be eliminated - all by century's end or even earlier.

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