The thing is that most of our current action plan for climate change consists of reducing CO2 emissions, and this is woefully inadequate for a world that the most recent science indicates has already passed the tipping point. Among the second-order changes that we should be preparing for:
1. Migration as the new norm. A 4-5C temperature rise will shift equivalent biomes over 1000 miles northward/southward, and inundate large coastal areas where major populations are currently located. Major densely-populated areas will become uninhabitable, and currently uninhabitable areas will become fertile.
2. The collapse of governments, and of the nation-state system. When migration becomes the new norm, borders become irrelevant, as do settled homogenous populations. What's the new political organization look like?
3. Large temporary food shortages. Higher temperatures, higher rainfall, and higher CO2 levels actually mean that in the long-term, plant growth and agricultural productivity will increase, and the earth's carrying capacity should go up. But in the short term - a lot of our current crops are hyper-specialized to their existing climate, and land rights, water rights, & physical crop location become problematic. Food distribution becomes critical - we'll likely make enough food to feed everyone on the planet, but the people who grow it may not want to share (or may have the inability to trade) with the people who need it.
4. Expect to see more diseases emerge. Large migrations, changes in biomes, and increased human habitation of formerly virgin ecosystems all spell chances for pathogens to jump from animal hosts to people and spread widely.
Overall, I'm a lot more scared of the likelihood that humans will kill each other than that the environment will kill us. We have a unique tendency to blame each other for unwelcome changes rather than to adapt to them.