James Hansen and other promi­nent cli­ma­tol­o­gists are call­ing to bring the CO2 atmos­pheric level to 350 parts per mil­lion. In fact, an orga­ni­za­tion, 350.org, came around that ral­ly­ing cry. This is far more rad­i­cal than most politi­cians are will­ing to enter­tain. And it is not likely to be enough.

The 350ppm tar­get will not reverse the clock as far back as one may assume. It was in 1988 that we have had these level of car­bon con­cen­tra­tion in the air.

But wait, there is more to the story.

1988-levels of CO2 with 2012-levels of all other green­house gases bring us to a state of affairs equiv­a­lent to that around 1994 (2.28 w/m2).

And then there are aerosols.

There is good news and bad news about them. The good news is that as long as we keep spew­ing mas­sive amounts of par­tic­u­late mat­ter and soot into the air, more of the sun’s rays are scat­tered back to space, over­all the reflec­tiv­ity of clouds increases, and other effects on clouds whose over­all net effect is to cool­ing of the Earth sur­face. The bad news is that once we stop pol­lut­ing, stop run­ning all the diesel engines and the coal plants of the world, and the soot finally set­tles down, the real state of affairs will be unveiled within weeks. Once we fur­ther get rid of the aerosols and black car­bon on snow, we may be very well be worse off than what we have had around 2011 (a pos­si­ble addi­tion of 1.2 w/m2).

Thus, it is not good enough to stop all green­house gas emis­sions. In fact, it is not even close to being good enough. A carbon-neutral econ­omy at this late stage is an unmit­i­gated disaster.

There is a need for a carbon-negative econ­omy. Essentially, it means that we have not only to stop emit­ting, to the tech­no­log­i­cal extent pos­si­ble, all green­house gases, but also cap­ture much of the crap we have already out­gassed and lock it down. And once we do the above, the ocean will burp its excess gas, which has come from fos­sil fuels in the first place. So we will have to draw down and lock up that car­bon, too. We have taken fos­sil fuel and released its con­tent; now we have to do it in reverse—hundreds of bil­lions of tons of that stuff.

Reality can­not be nego­ti­ated with. We have tried this. It did not work. Time to get real.