Keeping warming below the agreed-upon definition for the threshold of dangerous climate change, 2°C above pre-industrial levels, will be very difficult, since we've already blown two-thirds of our budget, and there is little time to act. Despite growing efforts to slow them down, CO2 emissions increased by 2.2% per year between 2000 - 2010, hitting the equivalent of 38 Gigatons (Gt) of CO2 per year in 2010. If we continue to follow this "business as usual" course, we will reach the 2,900 Gt limit just 17 years from now, in 2031, according to an analysis done by the Carbon Tracker Initiative. The International Energy Agency warned in 2012 that "almost four-fifths of the CO2 emissions allowable by 2035 are already locked-in by existing power plants, factories, buildings, etc. If action to reduce CO2 emissions is not taken before 2017, all the allowable CO2 emissions would be locked-in by energy infrastructure existing at that time."
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Avoiding Dangerous Climate Change Is Affordable If We Act Now
The cost of keeping global warming under the "dangerous" level of 2° C will only reduce "consumption growth" of the global economy by 0.06% per year if we start immediately and act strongly. Since consumption growth is expected to increase between 1.6% and 3% per year in the coming decades, we’re talking about annual growth that is, for example, 2% rather than 2.06%. This is a small price to pay to greatly decrease the risks of increased hunger, thirst, disease, refugees, and war that will result otherwise.
We're On Course for 4°C (7°F) of Warming by 2100
Our current business-as-usual emissions path (RCP 8.5) is more likely than not to cause 4°C (7°F) warming by 2100. That amount of warming is expected to result in "substantial species extinction, global and regional food insecurity, consequential constraints on common human activities, and limited potential for adaptation in some cases (high confidence). "
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Commentary
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There is no “critical threshold” that will be crossed when warming exceeds 2°C, sending us into a dangerous climate regime with greatly increased risks. Given the wildly erratic behavior of our jet stream in recent years, I believe we have already crossed one critical threshold into a more dangerous climate.
The 2°C limit is more like a speed limit--a convenient mark to set, above which the dangers are much greater. A more reasonable speed limit for the climate is 350 parts per million (ppm) of carbon dioxide in the atmosphere, a level we passed back in 1987. The climate activist group 350.org based their name on this lower speed limit. Since CO2 levels passed 400 ppm this year, I argue that we are already traveling 15% higher than the "safe" speed limit of 350 ppm.
If we do manage the very unlikely feat of keeping warming to 2°C, atmospheric CO2 levels will stabilize near 500 ppm--like traveling 100 mph on an expressway where the speed limit is 70 mph, an extremely risky proposition. If an ambitious global legal climate agreement is signed at the critical December 2015 Conference of Parties (COP) negotiations in Paris, and followed up with strong action over the next twenty years, we have a fighting chance of keeping warming to 3°C (about 700 ppm of CO2.)
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If we are to preserve any hope of a livable climate for our children, the fossil fuel industry cannot be allowed to burn anywhere close to the $27 trillion worth of fossil fuel reserves on their books, or be allowed to develop significant new resources. Given the massive wealth and political power of a fossil fuel industry intent upon preserving this $27 trillion stock value, it's no wonder that the dire messages on climate change given by the Nobel prize-winning IPCC, a volunteer organization with almost no PR budget, are drowned out by a stupendous amount of industry-funded misinformation, echoed by politicians they help elect and sympathetic media outlets.
Read original article at IPCC Final Report: We've Blown Two-Thirds of Our Carbon Budget
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