What will happen if our planet’s atmosphere warms 2 degrees Celsius during this century? I don’t know. I haven’t seen studies of warming to that extent (and I would welcome any links to studies that exist.)
What we’ve seen is mostly media reports of what will happen if temperatures rise much higher and most of those reports are pretty over-dramatic. But a careful study of modest temperature rises would be useful–after all, even if temperatures do climb higher, they will pass through the 2C range and perhaps stay there for quite a while.
The impacts that I have seen discussed are mostly on an unspecified gradient, which may be the best climate science can do at present. At some point between temperature rises of 1C and 4C, disruptions of large scale weather phenomena, such as the monsoon cycle, are expected to occur. But we don’t know at what point.
Similarly, although CO2 helps plants to grow and to use less water, there is a drop off effect–after a certain point CO2 doesn’t help as much. At what level of warming will we see the break point for CO2?
We really haven’t seen the projected climate refugees or climate deaths so far this century, but I would tend to assume that the hiatus in global warming is at least one plausible explanation for our good fortune. But I haven’t seen a linking between specific levels of warming and deaths or conflicts. Is any warming certain to cause people to flee their homes due to drought, storm or flood? Is any warming enough to cause the next Syrian refugee crisis? Or are there threshold levels? If so, what are they?
Are impacts expected to be linear? Are there step changes? I’ve read all the IPCC reports and still don’t have an answer to any of these questions. Perhaps I read too casually. If so, again, please point out to me where I should continue my investigation.
This stuff matters.