> It is, I promise, worse than you think. If your anxiety about global warming is dominated by fears of sea-level rise, you are barely scratching the surface of what terrors are possible, even within the lifetime of a teenager today. And yet the swelling seas — and the cities they will drown — have so dominated the picture of global warming, and so overwhelmed our capacity for climate panic, that they have occluded our perception of other threats, many much closer at hand. Rising oceans are bad, in fact very bad; but fleeing the coastline will not be enough.

http://nymag.com/daily/intelligencer/2017/07/climate-change-...

The IPCC, which is the official authority on climate change, believes that there will be 2-3 degrees C increase in temperature over the next century.

When someone can rationally talk about what will happen in the IPCC predicted scenarios, which is the scientific consensus, then I will listen to them.

If you are some crank, who is talking about 1000 parts per million of C02, and 10 degrees C temp increase by 2100, well then you shouldn't be taken seriously.

The part you may want starts around footnote 20, in a paragraph that notes 4 degrees as a median projection from the IPCC, with up to 8 degrees at the high end of the curve without factoring in permafrost melt and its associated carbon release or any of a variety of other exacerbating factors (footnoted in the article).

There are ways to calculate how much effort or expense is reasonable to attempt to mitigate a risk, I believe that's often part of the job description of actuaries. Part of it involves figuring out what the cost is if the event in question happens, then what the likelihood of the event is.

The doomsday scenarios may be uncertain, but they do not (to my layman's understand) seem impossible https://en.wikipedia.org/wiki/Clathrate_gun_hypothesis

For example, it explicitly mentions 10 degrees C of warming over the next century.

A 10 degrees C scenario is not something that any respectable scientist believes is going to happen.

The IPCC, which is the official authority on climate change, believes that there will be a 2-3 degrees C increase in temperature over the next century.

Thats the facts. Please listen to the scientists. Every single doomsday prediction that this guy is making, can be traced back to this fundamental problem that he is talking about scenarios that the experts and the scientists do NOT believe has even a remote chance of happening.

"a sufficiently large warming (roughly estimated as 5–6 ◦C, see Robinson 2000) would inevitably lead to an ecological disaster resulting in a complete depletion of oxygen."