The 'Bathtub' Climate Model Explained

The circuit of carbon in nature is a phenomenon that is not yet well understood, with new discoveries done almost on a daily basis. Yet, knowing how much carbon goes out in the atmosphere and how much gets trapped in the soil, plants and water is essential for figuring out the exact nature of global warming, as well as for assessing the level of danger we are in accordingly. Researcher John Sterman from the Massachusetts Institute of Technology (MIT) proposes the “bathtub effect” of the environment, a model that may help those failing to see the scale of global warming come to terms with what's been happening on Earth for the past years.

This model is fairly simple to understand. It states that the carbon circuit in nature can be likened to a vortex created in bathtub water when it goes down the drain. The water gets sucked down very rapidly, but still it keeps coming, which may end up by clogging the whole system, warns Sterman, who is a prominent analyst of risk perception and management at MIT's Sloan School.

At this point in time, carbon dioxide is emitted in the atmosphere at a rate that is twice as high as the rate with which our planet can absorb the dangerous greenhouse gas. The oceans and forests, traditionally the most efficient carbon sinks, are now in danger of becoming oversaturated with carbon, which means that they will lose their abilities to store the needed amounts.

And Sterman warns that, in a regular tub, the clogging of the draining system means flood. The situation is relatively similar on the scale of our entire planet, considering the fact that carbon remains in the air if it has no place to go. And once the trees, for example, stop taking in carbon because they are already full, the rate at which the dangerous chemical will accumulate will increase drastically.

In addition, by that point, cutting down wood would become virtually impossible, seeing how every single severed tree will release the important amount of carbon it has sequestrated over the course of its life. “The erroneous belief that stabilizing emissions would quickly stabilize the climate supports wait-and-see policies but violates basic laws of physics,” the researcher said.

He argues the necessity of urgent climate action, so that the danger threshold will not be reached and surpassed. If we allow for this to happen, then it may already be too late to restore the balance of the carbon circuit at a later date. Sterman argues that preventive action should be taken instead, to ensure a better climate for future generations.