Well they projected it to take a few decades... a few decades ago

To my knowledge, there had been an understanding that scientists were being fairly conservative with their statements of how bad things were going to get, and how fast it was going to happen.

I know of two primary drivers for this (which I am somewhat oversimplifying for brevity):

1. Scientists really didn't want to get it wrong by saying X will definitely happen by year Y, and then be wrong, thus giving ammunition to climate deniers and vested interests running counter-PR such as oil companies.

2. Scientists didn't want to paint a picture of unstoppable, inevitable doom that no person could possibly imagine a way for them to fix, or contribute towards fixing, thus leading to the mindset of 'if there's no way to stop it why even try?'.

Emissions haven't been constant over those few decades; fossil fuel burning has been rising about 3% each year, so that half the cumulative CO2 emissions since the industrial revolution have happened since the early 1980s.. That's what took us from "predicted change" to "crisis" now instead of at some earlier time.

That's the whole point. They're surprised that it's happening so fast. The acceleration at which things are happening has gone far beyond anything they predicted. My local area hit 40°C a couple of days ago, the highest recorded temperature on record since we started taking temperatures. We've had constant temperatures in the high 30s for the past 2 weeks. I can't remember temperatures this high and I'm almost in my fifth decade on our little blue dot. The icebergs that we see every year failed to show up this year because of the large amount of melt happening in the Arctic, something I can't remember seeing in my lifetime. I know what I'm saying is all anecdotal but there's also plenty of evidence supporting global atmospheric warming that's backed up by scientific data.

the climate changes greatly improve the likelyhood of extreme events, going from once in a million years to once every few years.

I bet you they are as surprised as you are...

Nothing gets me more depressed than climate crisis these days tbh...

There were a lot of different models, including some that were really close to the timelines we see now. All of those depended on different amounts of emissions, and if humanity took this seriously as soon as it was discovered the rate of change would be wildly different.

But there were very little significant changes to curb the emission rate, so we’re currently following the path of some of the worst predictive models. They still existed, just weren’t publicized as much as those that counted on some more reasonable approaches.

A good hardy "Our expectations were low, but holy fuck" and "we told you so" as we ride this planet into a slow hellish oblivion.