Joseph Romm is one of the most respected writers on climate policy. Here is a summary of his thoughts on what is necessary to avert catastrophic warming:

We have to bring down the amount of CO2 in the atmosphere to between 350-450 parts per million (ppm) to avoid the hellish worst of climate change. Economically and technologically, this is quite doable. However, it is not plausible in the current political climate. Because the alternative is unacceptable, we will get there, but to do so we must all become familiar with the best solutions, and then loudly push our political leaders toward them.

The solution is centered around achieving ~14 “stabilization wedges”. One wedge = one billion fewer metric tons of CO2 emitted globally, compared to projected levels. Again, this is possible with current technologies, and has a net cost of zero. The basic strategy is to replace all coal as quickly as possible, and to electrify transportation as much as possible.

Pacala & Socolow's Stabilization Wedges

Though there’s no silver bullet, but there is “one” solution: we must deploy every conceivable energy-efficient and low carbon technology that we have today as fast as we can. In order to reach the target carbon concentration of 350ppm, we have to deploy all 14 wedges of energy savings by 2040. Though increasingly serious implementation will begin soon, starting around 2030 multiple climate-caused catastrophes will cause drastic measures unthinkable today to be implemented. We must reverse the trend of increasing emissions by 2015-2020 at the latest, and we must have substantial action before 2012 or we’re toast.

There are about 18 wedges possible, and we need about 14 of them to succeed. Here are the options:

Currently available (14.5):

  • 1 wedge – albedo change through white roofs and pavement ( “soft geo-engineering” )
  • 1 wedge – vehicle efficiency: 60mpg standard for all cars, no increase in miles driven
  • 2 wedges – wind: two million large wind turbines
  • 3 wedges – Concentrated Solar Power aka Solar Baseload
  • 3 wedges – energy efficiency: one each for buildings, industry, and cogeneration/heat-recovery (also geothermal heat pumps)
  • 1 wedge – solar photovoltaics (PV)
  • 2 wedges – end deforestation AND plant new trees covering an area the size of the United States
  • 1 wedge – massive conservation post-2030
  • 1/2 wedge – nuclear (more not plausible, and it’s expensive, too)

Requiring more R&D (4):

  • 1 wedge – geothermal & other ocean-based renewables (wave, tidal, ocean thermal)
  • 1 wedge – coal with biomass cofiring WITH carbon capture & sequestration (more not plausible, and it’s expensive, too)
  • 1/2 wedge – next-generation nuclear
  • 1/2 wedge – cellulosic biofuels for long-distance transport & remaining aviation
  • 1 wedge – soil & biochar

There will, of course, be substantial up-front investments. However, they are a drop in the bucket of global GDP: 1.1%, or approximately one trillion dollars per year.

The IPCC, The McKinsey Global Institute, and the conservative International Energy Agency all report that the cost of this strategy will reduce global GDP by less than $1 for every $10,000. Because the huge costs of dealing with climate change will largely be avoided by this strategy, it is a net gain for the global and US economies.

For more detail, see the original posts, here, here, and here.