What should our national carbon emissions reduction goal be?

Our goal should be to create an economy substantially independent of the burning of fossil fuels.

Notable organizations and leaders have endorsed a goal for developed nations of reducing carbon emissions 80% by 2050, based on climate science considerations.

• Nicholas Stern report to the UK Treasury — a broad and thorough goal setting analysis.
• United Nations Framework Convention on Climate Change — executive director has endorsed the goal.
• NASA Scientist Jim Hansen:  reduce CO2 in next decade; also reduce other pollutants.
• Endorses not more than 1 degree C above 2000 temperature, 450ppm of CO2 or less (for more of Hansen’s argument on this, see Atmospheric Chemistry and Physics or Proceedings of the National Academy of Sciences.
  • Need for immediate action. (NY times book review of Inconvenient Truth).
  • Likely only course of planetary rescue is developing a means to extract carbon back out of air.
• State of California
• The United States Climate Action Partnership — see their report at page 7.
• The Natural Resources Defense Council.  See their rich document collection.
• Union of Concerned Scientists
• Many members of congress.
• Step it Up advocacy organization – links to many grassroots organizations.
• See a similar position from the European Environmental Council.
• For many references to this goal, google “carbon 2050 80”.

Massachusetts and other states have adopted this goal in legislation.

Ultimately, however, this goal is probably not aggressive enough.

• it is based on a target atmospheric carbon dioxide concentration which is high enough to cause significant negative climate change in many parts of the globe;
• it makes generous assumptions about the global carbon budget which is necessary to achieve stabilization at that concentration;
• it is consistent with a continued dramatic disparity between the United States per capita contribution to global warming and the global average;

(Currently, our per capita carbon production is roughly 5 times the global average. If, holding population constant, the global average must drop by 1/3, then, even if we feel entitled to pollute at three times the world average per capita, our average over the century would need to drop to 6/15 (3 x 1/5 x 2/3) or a cut of 60% from our current level. One cannot draw a straight line graph of emissions levels that averages 60% below current levels over the course of the century, but remains above zero at the end of the century — big cuts have to come in the first half of the century. If we assume a linear drop over the first half of the century from 100% of current levels in the first decade, to 80% in the second, and so on, stabilizing at 20% of current levels in the fifth decade and remaining there over the balance of the century, we achieve a 60% reduction on average over the century.)

• it assumes that, despite that dramatic continued disparity and despite the possibility of continued population growth and economic development, other nations will, on average reduce their carbon consumption by approximately one third by 2050 and continue further reductions in the second half of the century.

Moreover, aside from climate predictions, there are many other equally urgent reasons to reduce fossil fuel consumption:  Ongoing and recurring wars over fossil resources, economic dependence on unfriendly powers, and environmental destruction — deforestation, particulate pollution, toxics — from extraction and burning of fuels.  In addition, the supply of petroleum may soon be inadequate to meet world demand.

I support aggressive short and medium term plans to reduce fossil fuel use through efficiency and renewables.

The following sources address the broad question of goal setting in some depth:

• The Stern review, commissioned by the U.K. Treasury to study the economics of climate change.
• The Hadley center for weather in the U.K. summary on climate change goals.  (The Hadley center offers a wide variety of climate change information online.)
• The International Panel on Climate Change (the authoritative source on scientific issues, provides useful background, but does not directly engage coal setting).
• The Carbon Equity Project in Australia (argues for a 95% reduction by 2030 for Australia and by implication the United States).
• The Natural Resources Defense Counsel (offers a number of publications on alternative goals and emissions trajectories);
• The International Scientific Steering Committee (goal assessments towards stabilization)
• For another argument, see Setting a long term climate objective.

For a November 26, 2008 discussion of developments that have occurred since the most recent IPCC report (2007 Fourth Assessment), see this link for testimony of Jim Hansen before a British Parliamentary committee and this page for notes.