What to do about climate change? Initiate the Process. The first few steps being: define the Problem, then specify what you want to accomplish (the goal) and what you want to avoid. The Problem is the projected ongoing rise in global temperatures (due to increased concentrations of GHGs).  The goal is to keep the rise within this century to no more than 2°C. What we want to avoid is any net increase in human mortality and poverty, as well as any significant decline of non-human species. In other words, limit the extent of climate change and do so in a way that protects the entire biosphere.

Note that protecting the biosphere doesn’t necessarily mean keeping existing wild habitats in their “natural” state.  A 2°C rise in global temperature will still be very disruptive. Human intervention and species relocation will be part of the story.

Limiting global temperature to +2°C by 2100 would be roughly compatible with two of the four Representative Concentration Pathways (RCPs) provided by the Intergovernmental Panel on Climate Change (IPCC), as in the following chart:

 ProblemScenario2081-2100: Mean and likely range

  1. RCP2.61.0 (0.3 to 1.7) °C
  2. RCP4.51.8 (1.1 to 2.6) °C
  3. RCP6.02.2 (1.4 to 3.1) °C
  4. RCP8.53.7 (2.6 to 4.8) °C

The goal, then, is to stay within RCP2.6, or at worst, the low end of RCP4.5. Part of figuring out if this is even feasible requires us to look at the assumptions that were required to arrive at RCP2.6 and RCP4.5. Are these assumptions realistic, based on current trends?

Next: looking more closely at RCP2.6 and RCP4.5