Earth at risk of becoming 'hothouse' if tipping point reached

A study by scientists says global average temperatures will be 4-5C higher

A study by scientists says global average temperatures will be 4-5C higher

"Places on Earth will become uninhabitable if "Hothouse Earth" becomes the reality", co-author Johan Rockström, former executive director of the Stockholm Resilience Centre, said in a statement.

Average global temperatures are now 1C above pre-industrial times, a trend that the scientific community has mainly blamed on man-caused climate change.

The report notes that a 2 C temperature gain for the Earth could activate "important tipping elements" that would raise the temperature of the planet even higher creating a domino effect that could take the Earth to even higher temperatures.

"Climate and other global changes show us that we humans are impacting the Earth system at the global level", co-author, Katherine Richardson, of the Center for Macroecology, Evolution and Climate at the University of Copenhagen, said in a statement.

They said that "Hothouse Earth" is likely to be risky to many and uncontrollable.

"Global average temperatures are now just over 1C above pre-industrial temperatures and rising at 0.17C each decade", added Professor Steffan.

By the end of the century or maybe even earlier, storms would cause devastation on coastal communities, rivers would overflow, and coral reefs would be eliminated. This would cause flooding in the coastal land where hundreds of millions of people live. At this point, the global temperatures are already one degree higher than pre-industrial times.

Phenomena such as wildfires are equally worrisome to experts. Massive fires could accelerate carbon dioxide build up and add to global warming.

The scientist who compiled the "Perspective" article based their conclusions on previously examined conditions the Earth has experienced and previously published studies on tipping points for our planet. Currently, Earth is at 400 ppm. The stated 2 C no-return threshold is new according to scientists.

"It's rather selective, but not outlandish".

Fossil fuels must be replaced with low or zero emissions energy sources, and there should be more strategies for absorbing carbon emissions such as ending deforestation and planting trees to absorb carbon dioxide.

However, this won't guarantee that humans can avoid the path of destruction.

"This would be a planet that is not recognisable for us... as we know it", he told Shelagh Fogarty.

The feedbacks are permafrost thaw, loss of methane hydrates from the ocean floor, weakening land and ocean carbon sinks, increasing bacterial respiration in the oceans, Amazon rainforest dieback, boreal forest dieback, reduction of northern hemisphere snow cover, loss of Arctic summer sea ice, and reduction of Antarctic sea ice and polar ice sheets.

"Our study suggests that human-induced global warming of two degrees Celsius may trigger other Earth system processes, often called "feedbacks", that can drive further warming - even if we stop emitting greenhouse gases", said Steffen, lead author of the study published in the journal PNAS.

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