"We have been spending our planet’s capital for 250 years (since the start of the industrial revolution). We have the money to pay for fixing it, but some people in certain quarters don’t want to do that because they rather like their comfort the way it is.So what will happen if we don’t spend that $3.5 trillion?" Yep.
In my humble opinion, it is going to get worse. Much worse.
Two months ahead of the COP26 conference in Glasgow, the debate in the largest economy on the planet should be “How can we save what we can and how can we re-structure our lives, so we can eventually reach a plateau most of can survive on?” not “Can we afford $3.5 trillion over 10 years?”