tundras are emitting carbon at a rate of 0.1% an year. Permafrost is more carbon than the atmosphere currently contains (and much of that is in the form of methane, a far more potent greenhouse gas than carbon dioxide). NCAR climate researcher David Lawrence found that virtually the entire top 11 feet of permafrost around the globe could disappear by the end of this century.
Using the first “fully interactive climate system model” applied to study permafrost, the researchers found that if we tried to stabilize CO2 concentrations in the air at 550 ppm, permafrost would plummet from over 4 million square miles today to 1.5 million. If concentrations hit 690 ppm, permafrost would shrink to just 800,000 square miles.
While these projections were done with one of the world’s most sophisticated climate system models, the calculations do not include the feedback effect of the released carbon from the permafrost. That is to say, the CO2 concentrations in the model rise only as a result of direct emissions from humans, with no extra emissions counted from soils or tundra. Thus, they are conservative numbers — or overestimates — of how much CO2 concentrations have to rise to trigger irreversible melting.
We must stay well below 450 ppm to save the tundra and hence the climate.
Significantly, none of the major climate models — including NCAR’s (!) — included this crucial tundra feedback in their forecast of future concentrations atmospheric impacts for the IPCC.
Yet the IPCC report says that to stabilize below 450 ppm, the world must average under 5 billion tons of carbon emissions a year for the whole century. Annual carbon emissions are currently over 8 billion tons and rising 3 percent per year. We need to cut that to 4 billion by 2050 and below 1 by 2100.
And remember the tundra has some 1,000 billion metric tons of carbon. In the future, losing a mere 0.2 percent per year of the tundra (in the form of CO2) would add two billion tons a year to our carbon emissions, yet that rate would still leave us with over 80 percent of the tundra by 2100, so it is not an especially fast loss rate compared to what we may see at 550 ppm or higher. And, of course, the greenhouse gas impact would be far greater if much of that carbon were released as methane.
The point is that once even a small fraction of the tundra begins to defrost, it makes efforts to stabilize anywhere near 450 ppm almost impossible. But again, should we get to 550 ppm or above for any length of time, then permafrost emissions (and other amplifying feedbacks) are likely to take us to 700 to 1,000 ppm and beyond, which is the end of life on this planet as homo sapiens have come to know it.
So, the only prudent option is to stay below 450 ppm, which is eminently doable from a technological and economic, though not (yet) political, perspective.
by Joseph Romm
If rulers dont have the politicall will, we should make it. If you love your children, if you like them to have good life, your bank balance will not give that. Only your green consciousness can provide that.
You must reduce your consumption.
Dont get adicted to advertisements
Reduce use of money. Dont let it concentrated. Buy local.