Effect of doubling CO₂ concentration on the climate: A prophetic prediction

What is it about?

The effects of climate change are a consequence of increased atmospheric CO₂ levels. CO₂, now recognised as a greenhouse gas, causes the Earth’s atmosphere to heat up, and this phenomenon eventually snow-balls into global warming. However, decades ago, a 1975 paper was almost prophetic in determining this outcome. The authors of the paper in question used a three-dimensional general circulation climate model with simplifications to pre-dict how the doubling of atmospheric CO₂ would affect the climate. This doubling warmed the troposphere, which is the atmospheric layer closest to the Earth’s surface. The troposphere’s thermal stability ensured that this heating was limited to the layers closest to the Earth. This, in turn, amplified surface temperatures, especially at the higher latitudes, where receding snow boundaries were observed. The authors also considered multiple parameters in their simulation, such as relative humidity, heat and energy balance, and hydrology, thus predicting a greater rise in surface temperature. Another finding was the effect of increased CO₂ on the hydrologic cycle. Rising temperatures caused a change in relative humidity, leading to altered absorption of solar radiation by the atmosphere (which, in turn, made temperatures soar). This cycle of arbitrary temperature changes, called greenhouse feedback, caused unreliable changes in precipitation patterns as well.

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Photo by NASA on Unsplash

Photo by NASA on Unsplash

Why is it important?

Though this study was done in 1975, it is relevant even today, due to the rapid and unchecked rise in CO₂ emissions. It explains the link between emissions, global warming, and climate change, which are now pressing issues. KEY TAKEAWAY: A rise in atmospheric CO₂ concentration consequently leads to global warming and climate change. Controlling emissions may help mitigate the effects of climate change to an extent.