2011-06-22 13:46:34The Most Likely Climate Disasters On The Horizon -- New paper and graphic
John Hartz
John Hartz

The Most Likely Climate Disasters On The Horizon

BY Ariel SchwartzMon Jun 20, 2011

From forest die-offs to melting Arctic ice, there are many possibilities for how climate change will affect the planet. But some have a larger chance of happening than others. Which should we be prepared for most, and working hardest to prevent?
It's impossible to predict exactly when or how climate change will spiral out of control, but a new study claims that it's possible to find the "climate tipping points" (with apologies to Malcom Gladwell)--the small changes that lead to dramatic shifts in the climate--by developing early warning systems that analyze observational data and look for signs that the climate is becoming unstable.

What are the tipping points that we should watch out for? The study ranks them from highest to lowest risk, and from highest to lowest likelihood. Luckily for us, the most likely also happens to be the least risky (what's some flooding in comparison to the collapse of all sea life in the ocean, right?). Here is what you should be worried for, from most to least problematic for our planet:

West African Monsoon Shift

Western Sub-Saharan Africa's annual monsoon occurs because of seasonal temperature and humidity differences between the equatorial Atlantic Ocean and the Sahara. If those start to change, that could mean an increase in drought and famine in the region. On a global scale, the impact of altering hydrological cycles that "regulate the moisture and heat budget of the atmosphere" could have far wider-ranging effects.

West Antarctic Ice Sheet Collapse/Greenland Ice Sheet Meltdown

Should the massive ice sheets on either end of the planet retreat, the obvious effect will be an increase in sea level rise. But that doesn't just mean that coastlines get more narrow. More water means that tsunamis and hurricane-driven storm surges become far more powerful.

El Niño–Southern Oscillation Amplitude Increase

An increase of the the El Niño–Southern Oscillation (ENSO) could cause the Pacific to shift to a permanent El Nino-like state, according to one study. As we know, El Niño brings massive climate shifts to the Pacific--making it permanent could result in an increase in natural disasters all along the Pacific rim.

Atlantic THC Shutdown

This scenario involves the ocean circulation triggered by differences in temperature and salinity in the water--otherwise known as the Atlantic Ocean's thermohaline circulation (THC). It's what causes the Gulf Stream and other ocean currents. If a shutdown results in freshwater continually flowing into the North Atlantic, it will cool areas like Ireland, Britain, and the Nordic countries .This could lead to increasing floods and storms, a collapse of plankton stocks, more frequent El Nino-like events, and even an oceanic anoxic event, where oxygen below the surface of the oceans becomes depleted. This could potentially kill most ocean life--and that would have dire consequences beyond our our worst imaginations.

Amazon Rainforest Dieback/Boreal Forest Dieback

People are rightfully concerned about the Amazon, but the massive loss of any major forest would be problematic. Fewer trees, paradoxically, means we will see more wildfires and in the long term, an increase in the amount of CO2 in the atmosphere (since trees in the forests store carbon).

Arctic Summer Sea Ice Loss

According to some predictions, the Arctic could lose its summer sea ice as early as 2013. This will mean more water in the ocean, which will ultimately lead to to higher sea levels and increased flooding. But though this tipping point is the most likely, it may also be avoidable. The Max Planck Institute for Meteorology contends that the loss of sea ice could be slowed or even stopped if overall climate change is slowed. If this doesn't happen, though, a loss of sea ice will speed up global warming and cause our climate to change irreversibly.

2011-06-22 16:07:50
Rob Painting

The El Nino-like state doesn't refer to a permanent El Nino, rather a warming of the central and eastern tropical Pacific greater than the Western Pacific. ENSO events are still expected to happen, but the evolution of the eastern/central warm pool will most certainly impact some areas, such as the Amazon.