Two, yes. Four, no way. According to the Royal Navy's Rear Admiral Neil Morisetti, climate change will impose new burdens on Britain's military forces and allied militaries for conflict prevention, conflict resolution and humanitarian relief.
"We could probably secure a 2C world. I think it most unlikely we would be able to secure a 4C world."
"The impact resulting in the loss of land and the loss of livelihoods is increasing the stresses in a number of vulnerable countries, countries where food, health and [rising population] are challenges. All of that is increasing the threat of instability in an already unstable world. We need to act now to manage the risk."
Climate change will become, in other words, a peacekeeping mission so long as it is controlled, limited to 2C. Beyond that it becomes a combat problem as an "already unstable world" succumbs to chaos and loss.
But the military may have misjudged this 2C thing.
Some experts, including a former chair of the Intergovernmental Panel on Climate Change, the IPCC, warn that even capping warming at 2C could still be devastating to the environment - and us.
“There is no such thing as a safe rise,” said Bob Watson, who was the chair of the IPCC from 1997 to 2002. “You will see food and water insecurity, human health problems, and sea level rise even with a 2 C rise.”