Reversing the slide towards catastrophic climate change will be
a monstrous undertaking, but the challenge is fundamentally political, not technological or economic. We
already possess, or are close to developing, the technologies required to replace fossil energy
with clean alternatives, and the cost of implementing them is modest relative to the size of the economy (in
fact, many of the solutions available are cost negative).
But they will never be deployed, in the time
and on the scale required, without coordinated political support: in incorporating the full cost of dirty
energy in its price, in imposing higher standards of energy efficiency and land use, and in mobilizing, by way
of incentives, the massive amounts of private investment required to finance the effort. How do we ensure that
the necessary political tipping point is passed before natural tipping points foreclose on our common
struggle to avoid disaster?
Scope and Size of the Challenge
Industrial GHG emissions are now roughly double their removal by land plants, the ocean and other
natural sinks, thickening Earth’s atmospheric “blanket” with each passing year. Atmospheric concentrations will
continue to rise until we overcome our political and technological inertias to cut emissions to below the removal
rate (assuming natural emissions have not themselves increased due to higher temperatures). Until concentrations drop back
to, say 330-350 ppmv (half-way between current and pre-industrial figures), global mean temperature will
continue to rise until enough trapped long-wave radiation can punch its way through the stabilized atmosphere (thicker
blanket) and into space to balance the incoming short-wave radiation from the sun. At that new global temperature,
the hotter climate will continue to evolve (melting glaciers, rising seas, species die-off, etc.) until distribution
of its extra trapped energy has reached equilibrium throughout the earth system. (adapted from Mental Models
of Climate Change, 2007)
A wonderful 1-hour PBS presentation, in several chapters, on growing awareness in the US
of the realities of climate change and the political realities that have impeded, and continue to impede, an
effecive response.
