“There is a bright side to this conclusion” said lead author James Hansen of Columbia University, “Following a path that leads to a lower CO2 amount, we can alleviate a number of problems that had begun to seem inevitable, such as increased storm intensities, expanded desertification, loss of coral reefs, and loss of mountain glaciers that supply fresh water to hundreds of millions of people.”
from Revised Theory Suggests Carbon Dioxide Levels Already in Danger ZoneWe can avoid multimeter sea level rise, the loss of the inland glaciers that provide water to a billion people, rapid expansion of the subtropical deserts, and mass extinctions — each of which is all-but inevitable on our current path of unrestrained greenhouse gas emissions.
The not-so-good news: We will probably need an ultimate target of 350 ppm (or lower) for atmospheric carbon dioxide — if you accept the analysis of ten leading climate scientists from around the world.
And yes, the authors of “Target Atmospheric CO2: Where Should Humanity Aim?” in The Open Atmospheric Science Journal are painfully aware we’re already at 385 ppm and rising 2 ppm a year. That is why they propose the self-described “Herculean” task of phasing out coal use that does not capture CO2 “over the next 20-25.” And that requires a global CO2 emissions profile that looks something like this:
[Note to Hansen et al: Big pet peeve — I think you confuse the general reader by labeling your y-axis “CO2 Emissions” while expressing the units in billion metric tons of carbon. This helps foster errors in the media and elsewhere (see “The biggest source of mistakes: C vs. CO2“).]
Actually, even the ultra-sharp emissions cuts depicted in the figure won’t do the trick. We would still need “reforestation of degraded land and improved agricultural practices that retain soil carbon” (aka biochar to the rescue) to “lower atmospheric CO2 by as much as 50 ppm.”
More not-so-good news: That kind of emission reduction isn’t going to happen, not even under President Obama, not even close. Heck, I doubt it would happen under a President Hansen. We just are not going to see 350 ppm this century. Unfortunately, the authors “infer from the Cenozoic data that CO2 was the dominant Cenozoic forcing, that CO2 was only ~450 ppm when Antarctica glaciated, and that glaciation is reversible.”
That is, if we stabilize at 450 ppm (or higher) we risk returning the planet to conditions when it was largely ice free, when sea levels were higher by 70 meters — more than 200 feet! Yet, “Equilibrium sea level rise for today’s 385 ppm CO2 is at least several meters, judging from paleoclimate history."
from The facts about overconsumption
These twenty-four graphs reflect the world economic growth of twenty-fold since 1900, at the yearly increase of 3% - projected out to 2050 - matching the projected global greenhouse gas 3% yearly growth, by 2050, when the world economy is forecast to be 400% larger than today's economy.
---
The increasing rates of change in human activity since the beginning of the Industrial Revolution. Significant increases in rates of change occur around the 1950s in each case, and illustrate how the past 50 years have been a period of dramatic and unprecedented change in human history (US Bureau of the Census 2000; Nordhaus 1997; World Bank 2002; World Commission on Dams 2000; Shiklomanov 1990; International Fertilizer Industry Association 2002; UN Centre for Human Settlements 2001; Pulp and Paper International 1993; McDonalds 2002; UNEP 2000; Canning 2001; World Tourism Organization 2001).
---
Nicholas Stern in Copenhagen argued that the current economic depression gives the world a unique, unrepeatable opportunity to tackle climate change and poverty. The resources that we need to transform the global economy, he explained – raw materials, skilled labour and industrial capacity – are now far more available, and at a far lower cost, than they were during the boom years, and we should use them.
(Note: You can view every article as one long page if you sign up as an Advocate Member, or higher).
