Category: geoengineering

Ask Ethan: Could We Just Build A ‘Space Sunshade’ To Counteract Global Warming?

“[A]s a fan of terraforming options in the solar system, especially Mars, I thought that I would leverage my knowledge to assuage the fears of innocents. In this case, I thought to myself “If global warming is such a critical issue, why don’t we do something ‘cheap’ and ‘simple’ like building a solar shade at a Lagrange point?"”

If you want to deal with all of our climate change issues, going beyond global warming and including things like ocean acidification, we’ll truly need to address the changing contents of our atmosphere and our continued burning of fossil fuels. But if all we truly cared about was reducing the temperature effects of global warming, perhaps we don’t need to reduce our greenhouse gas use at all. Perhaps we don’t even need to resort to potentially Earth-changing geoengineering solutions; perhaps we could simply launch what’s known as a Space Sunshade and block out a fraction of the Sun’s light before it ever arrived here at Earth.

Believe it or not, as launch costs decrease and new orbit-sustaining propulsion technologies come into being, this might be the cheapest and safest way to fight global warming. Here’s the science for the curious.

Pluto’s Mysteriously Cool Atmosphere Might Hold The Key To Fighting Global Warming

“Global dimming could someday provide a geoengineering solution to counteract the effects of global warming, if our environmentally-minded efforts to curb our emissions fail. The discovery of the haze-temperature connection on Pluto demonstrates, for the first time, that there are actual cases out there where this type of effect can serve to reduce the worldwide temperature by far more than humanity’s emissions have increased it. On the surface, it provides a new hope for geoengineering scenarios to mitigate global warming. However, there are side effects associated with having pollutants and potentially toxic particulates in our clouds, and therefore our rainwater. We must ensure, before embarking down such a path, that the cure isn’t worse than the disease.”

When NASA’s New Horizons arrived at Pluto, it discovered a slew of wonderful surprises and sights. It found reddish-brown terrain, ices, a complex atmosphere with hazes, and a temperature surprise: it was 30 K (54 °F) cooler than we would have expected. There are only three factors that normally control a world’s temperature: its distance from the Sun, its reflectivity, and the gases present in its atmosphere. But on Pluto, the hazes play an incredible role, as a new paper out today reveals. These hazes, made of complex hydrocarbons formed from ionized gases like nitrogen and methane, actually add heat to the atmosphere but cool down the surface, leading to a dramatic difference that’s more than 10 times cooler than the heating effects of humanity’s contribution to Earth’s atmosphere. It makes you wonder if this might hold the key to fighting global warming here on Earth.

We may not be in control of our planet, but we’re at the controls. It’s up to us to make the right decisions, and learning all we can about other worlds in the Solar System is certainly helping!