The summer of 2018 was an anomalous one across much of Europe, while extreme events are increasing in many parts of the world. And a new study warns: we risk a “hothouse Earth” effect.
What would a planet that is 4–5° Celsius warmer look like? Very, very different from how we know it now. Certainly less hospitable. And we are already beginning to see some signs: this year's scorching summer, which struck northern Europe. In various locations and across several countries, temperatures well above seasonal averages were recorded, and for prolonged periods. Heat peaks that led to widespread fires, the shutdown of nuclear power plants, and the loss of entire harvests. And what is striking is not the isolated cases, but the fact that the anomaly affected vast areas of Europe.
At the end of July and the beginning of August, Finland reached 30°C, and the image of reindeer seeking relief next to people in swimwear is still fresh in the memory. In Denmark, also known as "the breadbasket" of England, temperatures broke record after record: May 2018 was the warmest month ever recorded in the country, at 1.21°C above average (records go back to 1879).
Sweden, another Arctic country and Europe's largest producer and exporter of timber and wood pulp, was hit at the end of July by one of the most extensive fires in its history, comparable in intensity to those seen in Mediterranean regions. More than 50 were counted across the entire Arctic Circle. Also in July, a state of alert had been declared in numerous cities in the Netherlands: in Amsterdam, 12 bridges could no longer be opened to allow ships and boats to pass due to the expansion of the metal.
In Germany, records began as early as April, and August saw numerous cases linked to the heatwave: in Gotteszell, Bavaria, a railway line was closed due to the warping of the tracks, while near Kassel a motorway was closed because the asphalt was melting, having evidently not been designed to withstand high temperatures. In France, meanwhile, several nuclear power plants were shut down because the cooling water was too warm, while in Paris electrical substations failed due to excessive demand. Not to mention the devastating fires that struck Greece and the outskirts of Athens.
All the signs appear to be there. And they are not from the latest disaster film produced by Netflix. The continuous rise in CO2 emissions into the atmosphere only exacerbates global warming, and the new Ipcc report itself, to be published in October, appears to contain no good news — namely, the possibility of staying below 2°C.
And one of the confirmations comes from one of the world's best-known research centres, namely the Stockholm resilience center, which a few days ago published a study in Pnas (Proceedings of the national academy of sciences) stating that the Earth risks entering a dangerous phase of warming, which would settle well above 2°C.
Drafted in collaboration with the University of Copenhagen, the Australian national university and the Potsdam institute for climate impact research, the study examined the various feedback effects caused by rising temperatures, concluding that these would only serve to amplify the temperature increase and bring the planet to a dangerous "Hothouse Earth" effect, or "boiling greenhouse".
These processes include the thawing of permafrost, the release of methane from the ocean floor, the melting of summer Arctic sea ice and the reduction of Antarctic sea ice and polar ice sheets. "These feedback processes could potentially act like a row of dominoes. Once one is tipped, it pushes the Earth towards another," said Johan Rockström, co-author of the report published in the Proceedings of the National academy of sciences and executive director of the Stockholm resilience center. At that point, the planet would need to find a new "resilient" equilibrium point, and this will not necessarily be suited to the flourishing of Homo sapiens.
