What Killed the Dinosaurs Just May Save Humanity

Image Credit: Don Davis, Southwest Research Institute for Forbes

Lydia Wandmacher

The accepted theory for the case of the extinction of the dinosaurs—the great terrible lizards that once ruled the earth—is an asteroid impact. But the crash did not cause their death the way that most of us assume it did. Sure, there was an impact zone that wiped out everything within a certain radius. The real killer, though, was the fallout. Soot suspended in the air created a breathing hazard and blocked the sun’s rays. Without as much solar radiation, the planet cooled by fourteen to twenty-eight degrees Fahrenheit, triggering a chain reaction that wiped out the dinosaurs as well as three-fourths of life on land.

Almost 191 million years before dinosaurs ruled the land, a similar event took place—but yielded very different results. A very large asteroid collided with a very fast object in space somewhere between Jupiter and Mars, and the dust from this impact slowly made its way toward Earth. Scientists believe that this slow increase in dust was enough to trigger an ice age by blocking significant amounts of solar radiation. However, unlike the meteor that ended the dinosaur age, this event took place over a long period of time and was not the result of a direct impact, thus allowing life to adapt to dropping sea levels and colder temperatures. This, while an extinction event, also created a more heterogeneous world that led to diversification for those that survived.

The team researching this early event believes that it may reveal a potential solution to counteract the current climate crisis. They propose that a large asteroid could be captured and brought to a gravity-equal point between Earth and the sun to slowly produce dust that would block sunlight and cool the Earth. The projected cooling effect of such an effort would be three times larger than needed to offset the 2 degree Celsius increase in the global mean temperature. There is also evidence that the dust could help fertilize the oceans, leading to a drawdown of carbon dioxide from the atmosphere. Lowering temperatures and reducing amounts of carbon dioxide in the atmosphere are vital in controlling global climate change. While the idea of capturing an asteroid to cool the planet sounds like science fiction or a bad eighties movie, it could be the future.

Of course, there would be catastrophic consequences to failure in executing this plan. The theoretical basis for this potential solution does come from studying the second largest extinction event, which is an intimidating thought. In the face of an ongoing sixth major extinction, however, options are limited. The worst-case scenario would come if the asteroid were to leave its planned location and plummet into the Earth. The team claims this would not cause enough damage to create an extinction event, but an entire city could be lost.

There are a lot of questions left to be solved before any part of this plan can be attempted. Questions range from moral to legal to logistical. Who would be held liable for failure? There is not currently comprehensive space law to cover the failure of a global potential solution such as this. Who gets to decide to take such a drastic and potential globally dangerous measure? Does the potential risk of asteroids plummeting to Earth or triggering an ice age outweigh the potential benefit of reducing rising global temperatures? Reversing the issue in such a way may cause a cascade of other problems, so would it be better to focus on stopping climate-affecting activities here on Earth?

The team working on this issue does not give an estimate for how long it would take to cause the needed change. Is this a fast-enough solution for the precarious state that we find ourselves in? There may not be an agreed upon date of no return for climate change, but everyone can agree that the danger is fast approaching. The asteroid collision took a couple million years to trigger an ice age, and this is time we may not have to wait. Also, if this plan would more than triple the dust needed to offset increasing temperatures, there is a chance that it would cool the Earth too much.

Overall, the use of extraterrestrial dust to block solar radiation is a fairly new concept with limited research feasibility. There is a lot of research left to do before such an extreme plan with massive potential ramifications should be attempted, but it is one of only a very few potential solutions that could reverse the climate change rather than merely stalling the global temperature increases.