climate change

Value a forest, cool a planet

Cutting forests is the third-largest source of climate-warming carbon emissions today, larger than the emissions produced by either the US or China. Including them in a "carbon market" is a tempting solution.

It comes down to this: Today, trees are worth more dead than alive. This despite the fact that they stash away billions of tons of carbon in their soil and themselves and constantly inhale more carbon from the atmosphere. They also help regulate the earth's climate in other ways, influencing rainfall patterns far away, including in the US. And they contain unique plant and animal life, the economic value of which is only beginning to be understood.

Yet no dollar figure is placed on these vital services. Instead, tropical forests are cut down in favor of enterprises such as palm oil plantations or cattle grazing, endeavours that make money here and now. It’s easy to see why rain forests continue to disappear at an alarming rate.

A report to the British government this month suggests that the way to recognize the true value of forests is by including them in carbon markets. Polluters around the world could earn credits to offset their own carbon emissions by paying for forest preservation.

via Value a forest, cool a planet | csmonitor.com

A carbon sink needs to be valued as much as a carbon source. Making this really happen is of course very difficult, needing accurate forest cover mappings (now available), and strict enforcement in countries that may be hard to monitor.

The moral hazard of giving people money to do “nothing” of course is something conservatives will not like, but the trees are not doing “nothing”. Paying people for stewardship is not wrong. There would be an opportunity to change an extractive subsistence based economy into a service economy, with sustainable tourism, shade grown coffee, local guards and forest officers, etc.

I like this idea very much. Carbon offset markets have gotten a bad name recently, but a larger scale program is necessary.

Carbon Trends 2007

Emissions increased from 6.2 PgC per year in 1990 to 8.5 PgC in 2007, a 38% increase from the Kyoto reference year 1990. The growth rate of emissions was 3.5% per year for the period of 2000-2007, an almost four fold increase from 0.9% per year in 1990-1999. The actual emissions growth rate for 2000-2007 exceeded the highest forecast growth rates for the decade 2000-2010 in the emissions scenarios of the Intergovermental Panel on Climate Change, Special Report on Emissions Scenarios IPCC-SRES. This makes current trends in emissions higher than the worst case IPCC-SRES scenario. Fossil fuel and cement emissions released approximately 348 PgC to the atmosphere from 1850 to 2007.

Carbon Trends 2007.

This is very scary news, and there’s more in the carbon budget for the last 7 years released here. It shows a total lack of leadership from the US, Canada, and Europe, countries responsible for over 80% of the historical anthropogenic contribution.

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The oceans cannot absorb infinite amounts of CO2

While North Carolina and most of the South of the US reels under drought like conditions and the local newspaper is filled with all kinds of stories about water shortages, this one sentence, steeped in science-speak has caught the attention of climate scientists and general climate change worriers.

The third process is indicated by increasing evidence (P =0.89) for a long-term (50-year) increase in the airborne fraction (AF) of CO2 emissions, implying a decline in the efficiency of CO2 sinks on land and oceans in absorbing anthropogenic emissions.

Huh? What they’re saying is that while increasing CO2 emissions are rightfully blamed for the bulk of global warming, a not insignificant (18% to be precise) percentage can be linked to the fact that the oceans just are not absorbing CO2 at the rate that they used to. The reasons are yet unclear, but the trend can definitely be seen.

OceanUptake.jpg

The noise in the data is clear indication that there are many natural factors that greatly influence this uptake. But recent observational studies (not a free paper, look up reference 2, so I won’t link to it) in the North Atlantic are backing up this trend.

The reasons could be as simple as decreasing solubility with increasing temperature, or with increasing ocean acidity, who knows. But it points in the general direction of our climate models being in danger of underestimating climate change effects.

What does this mean for climate research? Well, there was a really interesting paper out in Science today (Reference 3, not free!) talking about the uncertainties in climate change estimates. The best guess (95% confidence interval) is between 2 and 4.5 degrees Celsius rise in temperature with doubling of CO2 levels in the atmosphere. But the probability graph around this estimate is not symmetrical, it has a long tail towards the right (>4.5 degrees). The paper discusses why this uncertainty is not related to model limitations, but is an inherent feature of the way climate change processes work, through non-linear feedbacks and multiplying processes.

What these observations tell us is that uncertainty in climate estimates is not a bug, it’s a feature and will never go away. Also, all the uncertainty is on the wrong side, meaning we’re always in danger of underestimating climate change. There goes one more excuse for not tackling climate change with all the urgency it deserves.

We will never predict how bad it will be, we only know it will be pretty bad, possibly worse.

1) Contributions to accelerating atmospheric CO2 growth from economic activity, carbon intensity, and efficiency of natural sinks — Canadell et al., 10.1073/pnas.0702737104 — Proceedings of the National Academy of Sciences

2) Schuster, U., and A. J. Watson (2007), A variable and decreasing sink for atmospheric CO2 in the North Atlantic, J. Geophys. Res., doi:10.1029/2006JC003941, in press.

3) Gerard H. Roe and Marcia B. Baker (26 October 2007) Why Is Climate Sensitivity So Unpredictable?Science 318 (5850), 629. [DOI: 10.1126/science.1144735]