Humans have caused 1.5 °C of long-term global warming according to new estimates

Long-term should be defined. We can cool the planet the same amount long-term. Why is it taken as a given that any warming is irreversible when we have historical natural patterns showing global cooling (ice age)?

Of course it can be reversed, it’s just vastly more expensive to do so. If your house is on fire and you don’t have insurance you don’t say “eh I can just build a new one”, you put the fire out.

I agree that warming is an important issue to address. I don’t agree that we know that it will be more expensive to cool. Space is cold and technology allowing heat to vent into space may be less expensive than we think.

Sure it's more accurate to say current known methods are expensive or have side effects. For example, Carbon capture is very expensive. Another example, is sulfur dioxide provides reflective properties which was artificially cooling the earth (from shipping exhaust) until it was banned because it causes acid rain and a host of health problems.

We'll probably find other interesting geo-engineering techniques over time, but it is very unwise to bank on future solutions. Many things, like nuclear fusion, have been "just around the corner" for years and years.

Climate change is accelerating at a rapid pace. Go look at a chart of CO2 emissions over time. I think people default to thinking we're in some stable or slow state, when we're far from it. We're not just increasing CO2 emissions, we're increasing the rate of emissions. Debt (tech, financial or otherwise) when you have a path to pay it off is a useful tool, but taking climate debt with no known good solution is very unwise.

I see your point. You assume though that the taking on of the debt will lead to the solution. I disagree. Its extremely unclear.

The transition away from CO₂-emitting technologies is already underway, driven by market forces alone—solar power, for example, is now cheaper than oil. Proposing a substantial increase in global debt to further accelerate climate initiatives would need to demonstrate the following:

1. Spending Wisely: Invest in technologies that work and also do not introduce more problems.

2. Trusting Who Spends: Governments or others must use funds on solving the issue (not just giving money to cronies).

3. Global Cooperation: Countries working together (does Russia who sees warming as helpful comply).

4. Dealing With Inflation: The plan should address the inflation it causes, as it will raise living costs for people already struggling.

5. Better Use of Funds: Proving this use of funds is better than spending on other global issues.