Stabilizing atmospheric carbon dioxide concentrations at 450 parts per million would still allow for climate change and ocean acidification leading to catastrophic losses – such as the destruction of the world’s coral reefs.

At anticipated rates of increase in emissions, it is expected that 450 ppm CO₂ will be reached before 2050. At that point, corals may be on a path to extinction within a matter of decades. By 2050, the remaining coral reefs could fall victim to ocean acidification. Such a catastrophe would not be confined to reefs, but could start a domino-like sequence of the fall of other marine ecosystems.

According to scientists at the Royal Society in London:

To ensure the long-term viability of coral reefs, the level [of atmospheric C02] has to be brought down from today’s 387 parts per million to significantly below 350 ppm.

The 350 ppm figure is based on simple correlation. The early 1980s brought the first isolated bleaching events, which were caused by ocean warming in response to earlier rises in carbon dioxide. These events were triggered when 320 ppm was passed. Levels were up to 345 ppm by the 1980s, and at today’s 387 ppm reefs are in serious decline due to repeated mass bleaching. As carbon dioxide continues to climb, ocean acidification will take an additional toll on these ecosystems.

Unless humankind puts on the brakes very quickly and aggressively (i.e. global reductions of 80% by 2050), we face a high probability of driving climate beyond the 2°C threshold taken by both studies as a “danger limit”.To remain at or below the two-degree threshold, emissions must be reduced drastically, beginning immediately. But physical reality is moving much faster than policy: the concentration of CO2 in the air is already too high, and the oceans are warming up much more quickly than the United Nations’ Intergovernmental Panel on Climate Change (IPCC) assumed just two years ago.

As the climate scientists at RealClimate write:

[E]ven a “moderate” warming of 2°C stands a strong chance of provoking drought and storm responses that could challenge civilized society, leading potentially to the conflict and suffering that go with failed states and mass migrations. Global warming of 2°C would leave the Earth warmer than it has been in millions of years, a disruption of climate conditions that have been stable for longer than the history of human agriculture. Given the drought that already afflicts Australia, the crumbling of the sea ice in the Arctic, and the increasing storm damage after only 0.8°C of warming so far, a target of 2°C seems almost cavalier.

But we can’t even get serious about taking the steps necessary to hit the 450 ppm target necessary to limit warming to 2°, much less take steps to get back below 350 ppm. Europe is unhappy with the Obama administration’s refusal to accept aggressive near-term goals for cutting greenhouse gases and to accept language that would limit the rise in global temperatures to 2° Celsius, or 3.6 degrees Fahrenheit, above pre-industrial levels. In L’Aquila, Italy, negotiators for the world’s 17 leading polluters have dropped a proposal to cut global greenhouse gas emissions by 50% by mid-century – developing countries argue that they shouldn’t have to slow or sacrifice their fossil-fuel-based economic growth to help the West atone for its historical consumption patterns. The G8 nations, including the U.S., did agreed this week to cut their emissions 80% by 2050, but failed to reach an accord on shorter-term targets. U.S. officials framed the L’Aquila climate-change declarations as progress. U.S. officials dismissed numerical targets for emissions reductions by 2050 as “largely meaningless anyway”, as the target is so far in the future.

The G8 emissions pledge is scientifically illiterate. The best estimate is that the world needs at least 80 per cent cuts in global emissions – not just G8 emissions – and probably more like 100 per cent, to stay below two degrees.

The world is light years away from mandating a binding reversal in global emissions.

Everybody knows what needs to be done to arrest and then reverse the rise in greenhouse gases: first and foremost, stop burning coal, the sooner the better. Don’t even think about methane hydrates or sources of unconventional oil such as tar sands. Stretch out the world’s remaining oil and gas as long as possible, while learning to minimize energy usage and transitioning to renewable sources such as wind and solar thermal.

But neither the world’s leaders nor publics have yet begun to come to grips with the seriousness of our plight or about global climate strategies. We’re still pretending that cap-and-trade schemes will force us to do what we otherwise cannot muster the will to do.

I had a behavioral psych professor at university who attempted to stop smoking by snapping a rubber band he wore around his wrist every time he took a puff. Cap and trade promises are nothing more than promising to snap rubber bands – someday, we’ll quit. Last time I saw my old professor, he was still smoking.