That's how humans have lived for almost all of human history; only in the last couple of centuries have a significant number of humans been able to have a standard of living much above bare subsistence.
> The economy needs to change
The economy is always changing, just like the climate. We certainly need people to be inventing new technologies and creating wealth; that's how the economy changes in response to changing conditions and changing needs.
What we do not need is a bunch of draconian centrally controlled policies that will do more harm than good, based on invalid alarmist predictions.
> The change can be planned and strategised intelligently
Nobody knows how to do that on a global scale. No such planning and strategizing has succeeded in the past. To use your phrase, reality has always kicked the ass of such planning and strategizing.
Fortunately, we do not need a central authority planning and strategizing everything. What we need is to do common sense things to make our society and economy more robust, and give people the tools they need to adapt to change in whatever way seems best to them given the unique conditions of their own lives, instead of having policies dictated to them from the top down.
There's a story that a Soviet minister of something or other was visiting London and asked some UK government official who was in charge of the daily supply of bread to the city. He was utterly unable to fathom the answer, which was "nobody". Central planners just can't get it through their heads that central planning doesn't work.
Most obvious is the definition of "deal with." During the ice age transitions "deal with" more or less meant "survive - barely."
If you're happy for humanity to "survive - barely" for the next couple of centuries, then perhaps you have a point.
But our definition of humanity is much richer and more interesting than it was at the end of the Younger Dryas some 14,000 years ago.
Now a reasonable definition of "deal with" is "survive without losing significant acquired knowledge or skill."
That's a much bigger ask when survival-critical choke points are all on the line, which include food production, water supply, and the loss of key living and working space on the coastlines are all on the line. And that's not even considering the general inhabitability of inland areas that will become increasingly prone to storms, floods, forest fires, tornadoes, and so on.
We can already see this happening. Denying it is a form of delusion, in very stark and literal terms.
In fact the political problem we're dealing with is a cult-like mindset that considers "the economy" more real than the physical environment it exists in.
The bottom line is that "the economy" is a quasi-religious political construct, while the real world is... the real world. The economy needs to change, because otherwise reality will kick its ass whether it likes it or not.
The change can be planned and strategised intelligently as an immediate priority, or it can be suicidally chaotic, with huge unplanned loss of acquired knowledge and future potential.
Those are the two extremes on offer. There are no others.
COVID-19 is a handy dry run. We'll see how we do.