Geologist: ‘Going to a world that’s more Cretaceous than we want to’

The new calculations also show that average global temperatures in the Mesozoic era were higher than in pre-industrial times. The continuing trend toward global warming has been caused in part by increased sun brightness and rising sea levels. “Ocean surfaces typically reflect less solar radiation than land surfaces, and since higher sea levels flood flat continental regions, this has also contributed to higher average global temperatures,” Landwehrs says. In addition, there have been fluctuations in carbon dioxide concentrations in the atmosphere.

According to new accounts, these particularly warm sections were brought about in the early and late Mesozoic era – that is, in the Triassic and Middle Cretaceous periods. Shortly before the abrupt end of the age of the dinosaurs, carbon dioxide levels fell again in the late Cretaceous period. That also ended the extended warm phase before the asteroid impact, according to scientists.

Unprecedented increases in emissions

However, there is no need to rely on a similar reduction in carbon dioxide concentrations, says Wagrich. Because the increase in human-caused emissions is unprecedented in its pace and the Ice Age, which is currently ending, has caused a “reversal to a global warming climate” that can be talked about relatively little at the moment. The last documented major development of this type was about 55 million years ago. Therefore, it is worth taking a look at the Cretaceous greenhouse, which will soon be honed in further research. Because: “We’re going into a more Cretaceous-like world than we actually want to,” says Wagrich.

Accordingly, more precipitation is expected in the Earth system. This is also confirmed by analyzes of fossils and rocks from the Middle Ages, according to the geologist: “We see it in sediments, we see it in weathering.” Some current weather phenomena can indeed be explained in this way.