Earth’s climate will slip past “tipping point” within 100 years

Nine key geographical factors have been highlighted as Earth’s critical climate controllers most at risk of slipping past their “tipping points”. This means that once damage reaches a certain point, there can be no recovery; the damage will continue in a downward spiral, amplifying global warming and environmental damage on historic scales. And as if climate news couldn’t get any worse, one such tipping point is only a year away… 

You can’t move these days for articles about climate change, global warming and environmental disasters. All this talk about impending doom and gloom can often lull you into a detached reverie thinking “what the hell can I do about it anyway?” Although sometimes the outlook seems hopeless, scientists are stepping up a gear to understand what is happening and why humans are having such an impact on our world. In the quest to understand the effects we are having on the planet, new research has drawn up a list of nine key factors and processes likely to change the Earth’s climate most dramatically. It is hoped that once we understand how these processes work, and how long we have until the point of no return, action could be taken to allow the climate to heal.

Prof. Tim Lenton from the University of East Anglia, UK, has identified when the tipping points are likely to occur for the nine key geological factors, and the next one is most likely going to be the collapse of the Indian summer monsoon, which is variable at best. The list is as follows (plus predicted time to tipping point):

• Arctic sea-ice melt (approx 10 years)
• Greenland ice sheet decay (more than 300 years)
• West Antarctic ice sheet decay (more than 300 years)
• Atlantic thermohaline circulation collapse (approx 100 years)
• El Nino Southern Oscillation increase (approx 100 years)
• Indian summer monsoon collapse (approx 1 year)
• Sahara/Sahel greening and West African monsoon disruption (approx 10 years)
• Amazon rainforest dieback (approx 50 years)
• Boreal Forest dieback (approx 50 years)

Many of the factors seem obvious. The melting of the Arctic ice for instance will cause a global rise in sea levels and a loss of ice cover causing Earth’s albedo to decrease (reflectivity decreases), amplifying the greenhouse effect. Also, El Nino in the South Pacific will occur more often, causing rapid and extreme changes in the large-scale weather structure; hurricanes, flooding, droughts and unseasonal shifts in the jet stream will become more and more common.

Some of the factors are perhaps less obvious. For instance, the collapse of the Atlantic thermohaline circulation would have a counter-intuitive effect on the north Atlantic, actually cooling the waters around Europe, North America and the Arctic. The thermohaline drives the circulation of the oceans, so should the Atlantic thermohaline collapse, water from the equator will stop drifting north, providing the warmth at such high latitudes. This effect is unlikely to slow the melting of the Arctic ice-sheets, but it will have devastating effects on biodiversity in the region.

“Society must not be lulled into a false sense of security by smooth projections of global change […] Our findings suggest that a variety of tipping elements could reach their critical point within this century under human-induced climate change. The greatest threats are tipping of the Arctic sea-ice and the Greenland ice sheet, and at least five other elements could surprise us by exhibiting a nearby tipping point.” – Prof Lenton

Although worrying, many of the tipping point projections could be averted should strong action be taken by the international community and individuals alike – after all, we can all contribute in some way.

Source: Telegraph.co.uk