During his inaugural speech, President Obama said, "...we'll work tirelessly to... roll back the specter of a warming planet." Specter is a powerful word to use, imbued with dark magic – a terrifying apparition and unreal appearance, a visible incorporeal spirit. But if the scientific synthesis of Mark Lynas in his new book, Six Degrees: Our Future on a Warming Planet, is correct, then President Obama has chosen his words wisely.

Mark Lynas has written a compelling book – and revealing its basic thesis does not spoil the read because he tells the details so well. Six Degrees is the story of the difference between the world we have now, and our world six degrees warmer. The lesson is simple: the time to act is now! Lynas has compiled and synthesized the work of numerous climate scientists and the Intergovernmental Panel on Climate Change (IPCC). His story unfolds, chapter by chapter, with a scientific description of the change that may occur with each successive degree (Celsius) of global warming.

As Lynas relates in Six Degrees, we are currently .7ºC warmer than we would be without the impact of greenhouse gasses added to the atmosphere by humanity. Even if we stopped emitting carbon today, scientists anticipate we would warm an additional .5 to 1ºC due to the thermal lag in Earth’s vast systems, especially in the ocean. However, we are not likely to stop emitting all greenhouse gasses today, and, according to projections by the IPCC, we are likely to continue the trend toward a world that is somewhere between 1.1 and 6.4ºC warmer by the year 2100.

At some point above 2ºC is when the specter of a warming planet begins to really sink in, due to biofeedback mechanisms that accelerate the pace and scale of change. Scientists increasingly fear that first we will cross a tipping point, causing Amazonia to collapse and release carbon from warming soils, pouring up to 250 ppm of additional CO₂ into the atmosphere and accelerating global warming in a positive feedback loop. As we cruise into a world that is 3ºC warmer, we enter a climate not seen since the Pliocene Era, when the sea level was 25 meters higher. But the specter continues – somewhere just over 3ºC we will cross another tipping point as the permafrost of Siberia melts, releasing vast quantities of methane (an even more potent greenhouse gas) into the atmosphere and further accelerating our march towards six degrees. The third major tipping point, known with less precision, but feared more greatly, is the possibility of causing an oceanic methane hydrate release somewhere close to 5ºC. This is literally an explosive release of methane into our atmosphere, sending us beyond a 6º C warming. At 6ºC global warming, it is likely that the mass extinction may exceed the “End-Permian Wipeout” when 75-95% of life on earth went extinct.

The key take-away from Six Degrees is that our safe landing zone is not more than 2º C global warming. The current financial crisis and specter of a warming planet give new meaning to the mantra that “de-carbonizing the economy is our greatest economic opportunity since we mobilized for WWII.” President Obama, please give the order: it is time we mobilized to defeat the specter of a warming planet!

PS. Please read Six Degrees and make up your own mind. Mark Lynas has compiled a great story and I apologize if I have prematurely spoiled it for anyone.