How quickly can we recover from global warming?

The answer is rather shocking: 20,000 to 50,000 years, according to the latest research.

Polling just completed shows that most Europeans are eager to have their leaders do something about climate change but are also unwilling to make any lifestyle sacrifice to make it happen. In the meantime, climate change is causing temperatures to rise and is also increasing the likelihood of storms, out-of-control fires, heavy rain, and flooding.

A recent UN study (reported in TR) showed that by the end of the century global warming will have increased by 3.7%--way above the Paris Agreement target of 1.5%.

The obvious question is, how quickly can the climate recover from the warming caused by an increase in carbon dioxide in the atmosphere?

A German team set out to investigate this aspect by considering the significant rise in global temperatures of five to eight degrees Celsius that took place 56 million years ago – the fastest natural period of global warming that has impacted on our climate, known as the Paleocene-Eocene Thermal Maximum (PETM).

It was most likely triggered by a volcanic eruption that released huge amounts of carbon dioxide or CO2 into the atmosphere.

We know that the higher the temperature, the faster rock will weather, and, in addition, if there is a lot of CO2 in the atmosphere, some of it will react with water, forming carbonic acid – the acid that promotes and accelerates the weathering process. Because of the weathering process, this atmospheric carbon will eventually find its way into the seas via rivers, where it binds CO2 as carbonate and form a persistent ocean-based reservoir of carbon dioxide.

What the researchers say: "Our theory was that if rock weathers faster due to the increased temperatures, it also helps convert a lot of carbon dioxide from the atmosphere into insoluble carbonate in seawater – meaning that, over the long term, CO2 levels would end up falling again and the climate would ultimately recover," explained the lead researcher.

This effect could have helped to keep the Earth's climate fairly stable over billions of years and it could have even prevented the total extinction of all life on the planet (maybe total extinction of all life is something not even Exxon Mobil wants—at least not before the CEO’s term ends?)

In order to test this theory, the team decided to analyze the weathering processes that occurred during the warming event 56 million years ago. Their findings indicate that the theory may well be correct.

"Rock weathering during that time increased by 50 percent as a result of global warming; erosion – the physical part of weathering – actually tripled. Another consequence of the rise in temperature was that evaporation, rainfall, and storms also increased, which then led to even more erosion. As a result of this increased rock weathering, the climate stabilized, but it took between 20,000 and 50,000 years for this to happen," they said.

But how did the researchers come to these conclusions? After all, these weathering processes took place 56 million years ago. The answer lies in the rocks themselves. When rocks dissolve, they release lithium – the isotopes lithium-6 and lithium-7 to be precise – which escapes into any surrounding water.

The proportion of the isotopes lithium-6 and lithium-7 present in water is determined by the type of weathering, in other words, the amount of erosion produced by weathering. Clay, which is found at the bottom of the sea, mainly stores lithium-6, while lithium-7 remains in the water. The research team conducted two types of scientific investigation: They examined marine carbonates that were formed 56 million years ago – a type of rock that absorbs chemical components from water. They also investigated clay minerals from Denmark and Svalbard, which also formed during this period, looking at the relative proportions of lithium isotopes in these two different kinds of minerals. The researchers were able to use the data obtained to draw conclusions about weathering and climate 56 million years ago.

Their results have been published in the journal Science Advances.

The Paleocene-Eocene Thermal Maximum is also used as an analog to draw conclusions about current and future global warming rates. The authors point out that in the future both weathering and erosion, including soil erosion, are likely to increase, as well as storms and extreme weather events – the recent floods in Germany and fires in Australia, Greece and the US West Coast are symptomatic of this.

So, what? An additional study, published on the same day as this one, finds that 99.9% of all studies on global climate change conclude that it is mainly caused by humans. The researchers based their finding on a new survey of 88,125 climate-related studies.

But as the European polling noted at the top of the story suggests, no serious steps to halt climate change are liable to happen. And, after all, in 50,000 years all will be well.

For more on climate change click here.