The Daily Climate 20 November 2012.
(Editor’s note: An excellent article – there might be hope for us yet! I wonder if black carbon is on the Doha agenda?)
Methane, soot and air pollution account for roughly half the additional warming influence expected out to 2100 by this century’s emissions.
Cutting their emissions could limit near-term climate change while providing considerable health and environmental benefits.
Much within Amy Luers’ recent Daily Climate essay on extreme weather and the climate crisis is to be commended. Indeed, cutting emissions of carbon dioxide (CO2) today won’t eliminate a climate change-induced pattern favoring more severe storms and extreme weather. In advocating for emissions cuts, the climate change community has to avoid backlash from a public expecting otherwise. Adaptation and resilience-building are essential to limiting impacts.
However, by aggressively cutting emissions of soot (black carbon), methane and air pollution (specifically tropospheric ozone), we can reduce the speed that the situation worsens. These compounds remain in the atmosphere only days to decades – versus centuries for the CO2 perturbation– so cutting their emissions can appreciably slow the rate of warming over the next several decades.
The different roles that long- and short-lived emissions play in climate change are important. So far, however, the international negotiating process has chosen to lump them into a single basket that assumes all greenhouse gases behave like CO2. This is like projecting the health of the Social Security trust fund by assuming everyone is a 40-year old male.
Halve projected warming
The importance of this distinction was made clear in a recent assessment led by atmospheric chemist Drew Shindell of NASA’s Goddard Institute for Space Studies [pdf]. Organized by the United Nations Environment Programme and World Meteorological Organization, the results indicated that a moderately aggressive international emissions control program focused on the short-lived compounds could roughly halve the projected warming between the present and 2050…