Scientists describe what a ‘hothouse Earth’ might look like

7 Aug 2018


Researchers fear that even if we meet our climate objectives with the Paris Agreement, a ‘hothouse Earth’ might still be inevitable.

After a week in which Europe was baked by record-high temperatures, an international team of researchers is suggesting things are only likely to get worse.

According to the researchers, even if the carbon emission reduction targets set out by the Paris Agreement are met, there is a risk we could still enter ‘hothouse Earth’ conditions.

If this were to happen, Earth would enter a long, stable period where the global average temperature would be between 4 and 5 degrees Celsius higher than pre-industrial temperatures.

By comparison, Earth’s current average temperature is a little more than 1 degree Celsius above the pre-industrial average and rising at 0.17 degrees Celsius per decade.

Even more worrying for those living on coasts, sea levels in these future conditions would be between 10 and 60 metres higher than today.

Carbon sinks to carbon engines

The authors of the study published to Proceedings of the National Academy of Sciences identified a number of natural feedback processes that could turn carbon sinks into carbon engines.

These include permafrost thaw, loss of methane hydrates from the ocean floor and the loss of Arctic summer sea ice.

“These tipping elements can potentially act like a row of dominoes,” said Johan Rockström, co-author of the paper and executive director of the Stockholm Resilience Centre.

“Once one is pushed over, it pushes Earth toward another. It may be very difficult or impossible to stop the whole row of dominoes from tumbling over. Places on Earth will become uninhabitable if ‘hothouse Earth’ becomes the reality.”

What can we do to avoid it?

To hopefully avoid such a grim future, the researchers said it requires not only a reduction in atmospheric CO2 and other greenhouse gases, but also innovative new biological carbon stores to absorb it.

This is possible through improved forest, agricultural and soil management, biodiversity conservation, and technologies that remove CO2 from the atmosphere and store it underground.

Then, of course, there is the fundamental shift in attitude needed by us humans towards a more sustainable society.

Katherine Richardson of the University of Copenhagen and a co-author of the paper, added: “Climate and other global changes show us that we humans are impacting the Earth system at the global level.

“This means that we as a global community can also manage our relationship with the system to influence future planetary conditions.”

Colm Gorey was a senior journalist with Silicon Republic