Time is of the essence.
*There is a “lag” in the climate system. There is also a lag when you use a blanket. You put it on, but it takes a few minutes for it to trap your body’s heat. In terms of the earth system, there is a 6.6 to 30.7-year lag between carbon dioxide emissions and the consequent maximum warming effect, as it takes a long time for the huge mass of the oceans to warm up.
We have released roughly half the greenhouse gases emitted in human history over the past thirty years. We’re only starting to feel those effects now. That’s why we need to both proactively adapt to this warming and mitigate it, by reducing net emissions to zero at wartime speed and removing excess greenhouse gases from the air until a safe climate is restored. Failing such an intervention, the earth's climate could shift into a state hostile to humanity — and even life itself — for many thousands of years.
*Feedback loops occur when changes caused by warming cause more warming. For example, the climate has become more conducive to wildfires in California and Colorado. As these fires have destroyed hundreds of thousands of trees, they have releasing carbon dioxide as smoke into the atmosphere, creating more warming. There are many such feedback loops that we know can occur, and likely others that are not yet known. Tipping points occur when irreversible feedback loops are triggered, and warming accelerates even without human emissions of fossil fuels, making it much more complicated for humanity to exert control over the fate of the climate.
*In fact, as they have been continuously revised in recent decades, scientists' projections have become even more daunting. The climate has surprised us with how sensitive it is. We must act now to provide ourselves with the best chance of saving civilization. As the American Association for the Advancement of Science put it: “The sooner we act, the lower the risk and cost. And there is much we can do. Waiting to take action will inevitably increase costs, escalate risk, and foreclose options to address the risk.”
Skeptical Science discussion of the 40-year climate lag
- NOAA’s page on feedbacks
Carbon stays in the atmosphere:
- Nature article Carbon is Forever
We need both adaptation and mitigation
- David Roberts, "Preventing climate change and adapting to it are not morally equivalent." Grist (2014).
- Wisconsin Media Lab: Adaptation and Mitigation
We must act now: