A Medium-Sized Asteroid Could Bring An Ice Age

It appears that a medium-sized asteroid could bring an Ice Age for the better part of a decade on Earth should it hit our planet on land. Given recent news of close fly-bys, it’s interesting to know what could happen. We will not be hit by asteroids for the foreseeable future, but what if?

• Researchers studied the consequences of a potential impact with a 0.6-mile-wide asteroid
• The collision would create a 9-mile-wide crater, and would release dust and soot in to the air
• It would cause average global temperatures to drop by 14.5^o F
• Precipitations would drop by 50% and the UV index will reach 20 in the tropics

A new study from the National Center for Atmospheric Research shed a little light on the matter of a potential asteroid impact. Specifically, their study focused on the possibility of a 0.6-mile-wide (1 km) asteroid hitting a landmass on Earth, as opposed to water. And, apparently, the consequences will be massive, long-term, and highly detrimental to the health of the planet. In turn, it will also become a major negative influence on humanity.

First of all, the impact would create a 9-mile-wide crater (15 km). This will throw large amounts of dust into the atmosphere. Barring the asteroid landing in a desert area with little vegetation, the collision will also trigger numerous wildfires, which will send tremendous amounts of soot into the air. This will quickly make an impact on the protective ozone layer and temperatures around our world. And, unfortunately, these effects could last up to 10 years.

According to the study, the impact of such an asteroid will cause a significant impact on global average temperatures. Particularly, they will drop by 14.5^o Fahrenheit (8^o Celsius), which Charles Bardeen, stated that is “about the equivalent of the ice ages”. That is because the dust and soot will reduce the amount of sunlight we’re getting by around 70% in the first few years and then gradually lower to 20%. It will mean much cooler temperatures everywhere around the world, with a further negative impact on global agriculture, animals, and, of course, ourselves.

After the hypothetical collision with the asteroid, the dust will take up to 6 years to settle and the soot will remain in the atmosphere for 10 years. While this will temporarily cool down the planet, which might need it a little given issue of global warming, it’s not so beneficial and it’s not simple either. In fact, it will be temporary and the effects will still be felt long after. The chemical reactions that destroy the much-needed ozone layer will speed up.

It’s a vital protective layer that protects us from the Sun’s damaging rays. After the asteroid impact, it will be temporarily reduced by 55%. That means that the UV index will top at 20 in the tropics for a couple of years. It would be extremely dangerous, considering the U.S. Environmental Protection Agency describes an UV index of 11 to be “extreme risk of harm from unprotected sun exposure”. One can imagine what would happen if that number would be almost double.

Global precipitations will also be reduced by 50% which means bad times for agriculture. This would be especially the case in North American, Europe, and Asia. It will be cold and dry, and “these would not be pleasant times”, as stated by Bardeen.

However, what would be the impact if the asteroid hits water? After all, Earth is 70% water, so there’s a bigger statistical chance of it not making impact on land. According to Bardeen, the impact on the ozone layer will be much harsher. The resulting vapors will nearly destroy the protective layer, and will cause the UV index to temporarily reach 56. That means that everyone will be indoors during the day for their own safety.

However, the temperature and effects on the climate, such as rain, would not be as dramatic as a land collision.

Thankfully, the chances of such an impact are remote. NASA is tracking almost 13,000 near-Earth objects (NEOs), and only 1,607 of them are categorized as Potentially Hazardous Asteroids. Among them, 879 are at least 0.6-mile-wide as the one described in the study. However, none present with an immediate threat. And if one should set its crosshair on Earth, there are methods ready to be used against it.

If NASA has a 10-year notice on the potential impact, the asteroid could be steered off-course using “kinetic impactors” that slam into the space rock, “gravity tractor” probes that fly alongside it and slowly nudge it, or there is the potential use of destroying it with a nuclear bomb. And if all else fails, someone will get Bruce Willis on the phone.

Image source: wired.co.uk