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Comment by learc83 | Hacker News Reader

Picking and choosing predictions in this manner to make it look like they have all been steadily increasing is misleading.

Some of the initial predictions in the late 80s were for up to 6c by 2100.

The last IPCC report I saw predicted an increase of between 0.3C and 0.7C by 2035 with around 0.4C being the most likely. There is little support for numbers anywhere near as high as 3.5C by 2035.

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> Picking and choosing predictions in this manner to make it look like they have all been steadily increasing is misleading.

Those predictions are all sourced in the original article. As you say, though, pointing out a trend in the predictions from a set of scenarios doesn't on its own tell you anything.

> The last IPCC report I read predicted an increase of between 0.3C and 0.7C by 2035 with around 0.4C being the most likely. Nowhere near the the 3.5C by 2035. There is very little consensus for numbers that high.

Was that the fifth assessment report?

And where does the consensus 'currently' cluster for 2035? What climate models would be included? Under what emissions scenarios? I'm not too familiar with the state of the current literature.

Here is a graph with various model predictions towards 2100, under a "business as usual" scenario. As you can see, even the most pessimistic models are below 2C by 2050. I have no idea where 3.5C by 2035 came from, no models predict such a shocking rate. (We were only up ~0.7C over the last century.) Also note that none of these models reproduce the last decade's global warming hiatus; given that constraint, temperature predictions for 2100 will be slightly cooler.

https://en.m.wikipedia.org/wiki/File:Global_Warming_Predicti...

This discussion just confuses me completely. I'm a scientist (of the mathematical variety) and absolutely of the thought that human-made climate change is the largest current threat to human civilization.

But here we have at least seven different claims that vary wildly, from "catastrophe practically guaranteed" to "this problem can be handled in a straightforward way if we focus".

Given that I'm not a climate scientist, who should I listen to?

Some have criticized the IPCC report as too conservative/optimistic, but it is as close to a consensus document as exists.

Thanks, that's helpful. Is the IPCC criticism gathered in one place somewhere, or would it require reading a lot of different sources?

My understanding is that there's a fairly wide range of assumptions that can underlie a given model, which depend on what we will actually do about this. For example, how do you estimate CO2 output over the course of the next century? Do you assume that it remains at current levels, or keeps growing at the same rate it has been so far, or that whatever treaties were signed that promise to reduce it actually will?

Just listen to whoever says the thing you want to hear.

But keep this in mind: sometimes people say things to advance their own agenda.

The person you responded to asked a serious question. Your answer is in no way helpful or insightful.

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