Unfunded tax cuts doesn't make sense. It doesn't cost to have someone not pay a tax. The more accurate description would be insufficient tax revenue for given government expenditures.
The truth is that entitlements (government dependency / loss of liberty) far exceed any other spending category. That isn't to say money isn't wasted in other categories, only that it's less significant.
Collectively we have developed a narcissistic entitlement culture where we eat tomorrow's lunch and let our grandchildren pay for it. We have that attitude with resource consumption, pollution emissions, and economics.
Tell that to WWII survivors. Ask any old person what their top 10 most significant challenges were, and I doubt GW appears on their list. Ask an 80 year old how they coped with a sea level that rose 8" in their lifetime, and they will give you a blank stare. This is the same predicted rise for the next 80 years.
We are a significant contributing factor, but it's far from clear if the net negative impacts of GW outweigh the net benefits.
Its nice that we live in such a comfortable world in which the outdoor thermostat is something we can concern ourselves with. Much better problem to contend with than say, how not to starve to death, or how to keep invading hordes from killing us.