We are in trouble. Global carbon emissions are rising, not falling.

If there were any doubt before, there should be none now. “Solving” the global climate change problem may be humankind’s mission impossible. That’s the gist of the latest report from the Intergovernmental Panel on Climate Change (IPCC), the U.N. group charged with monitoring global warming.

Unless we make dramatic reductions in greenhouse-gas emissions (carbon dioxide, methane and others), warns the IPCC, we face a future of rapidly rising temperatures that will destroy virtually all the world’s coral reefs, intensify droughts and raise sea levels.

The IPCC says emissions need to be cut 45 percent from present levels by 2030 and virtually eliminated by 2050. This would keep the projected increase in global temperatures since the early 1800s to 1.5 degrees Celsius, or 2.7 degrees Fahrenheit. We would escape the worst consequences of global warming.

It’s not clear how this would be done. The reality is that global carbon emissions are rising, not falling. Emissions today are about 60 percent higher than in 1990, according to the World Bank. There are at least three obstacles frustrating the IPCC’s agenda.

First, we don’t have the technologies to reduce and eventually eliminate emissions from fossil fuels (oil, coal and natural gas). Yes, solar and wind power have made advances, but they still provide only a tiny share of the world’s total energy, about 4 percent.

Second, even if we had the technologies to replace fossil fuels, it’s doubtful that we have the political will to do so. Democracies — or, for that matter, dictatorships — have a difficult time inflicting present political pain for future, hypothetical societal gains.

Finally, assuming (unrealistically) that today’s advanced societies — led by the United States — overcome these obstacles, it’s unclear whether poorer and so-called emerging market countries would follow suit. These countries represent the largest increases in fossil-fuel demand.

Economic and population increases boost energy demand. Consider air conditioners. The world now has 1.6 billion air-conditioning units, reports the International Energy Agency. By 2050, that could triple to 5.6 billion units. People in advanced societies won’t abandon air conditioning, and people in poorer countries won’t surrender the chance to enjoy it.

What is to be done? Maybe nothing. This seems to be the choice made by many Republicans and the Trump administration. Trump’s hostility is not as crazy as it sounds. If suppressing global warming is as hard as I’ve argued, one likely response is a series of half measures that don’t much affect global warming but do weaken economic growth. The politicians’ real aim is to brag that they have “done something” when all they have really done is delude us. Trump would skip this stage.

My own preference is messier and subject to all the above shortcomings. I would gradually impose a stiff fossil-fuel tax (producing not a 10 or 15 percent price increase but a doubling or maybe a tripling of prices) to discourage fossil-fuel use and encourage new energy sources. In addition, some of the tax revenue could reduce budget deficits and simplify income taxes. With luck, a genuine breakthrough might occur.

There are risks. It can be argued that this sort of policy, aside from relying on unpopular energy taxes, would represent a triumph of hope over experience.

Combating global warming is a noble crusade, but it’s much harder than the rhetoric implies. If we were serious about cutting greenhouse gases, we could adopt comprehensive wartime controls that empower the government to mandate changes. Or we could accept a worldwide depression as a way to quash job growth and greenhouse gases. Obviously, neither is in the cards.

This story was originally published October 16, 2018 at 1:45 PM.