Something interesting is happening to greenhouse gas emissions thanks to the coronavirus pandemic: They are plummeting. The world is seeing the lowest oil demand relative to supply perhaps ever, leading to oil futures contracts selling for negative values at several points. The International Energy Agency estimates that this year world carbon dioxide output will fall by a whopping 8 percent. If that pans out, it would be the largest drop ever recorded — some six times larger than the fall during the 2008 global financial crisis.

That rate of decline is also approximately what would be necessary to achieve the goal of keeping global warming under 1.5 degrees Celsius, if maintained for the rest of the decade. Thus the coronavirus lockdown is showing us roughly the scale of what is needed to avoid extreme climate change effects — but an extremely clumsy way of achieving it. The world could have a full employment economy and attack climate change at the same time, if humanity really put its mind to it.

For many years now, one school of thought among environmentalists has advocated "degrowth" as a strategy for dealing with climate change. By this view, green austerity policies would slow the economy, reduce carbon emissions, and cut the global burden of humanity on the biosphere. We see today that such a strategy could indeed work, if carried out on a grand enough scale. It could be done more or less sensibly, as lockdown policies have been better planned in Europe and a haphazard disaster in the United States, but basically we would have to strangle the world economy to death — after all, this 8 percent decline is only the start of something that would have to deepen steadily for the next 20 or 30 years.

But the coronavirus shutdown also demonstrates how incredibly devastating and unpopular such a policy would surely be. Despite protests otherwise, it would almost certainly mean mass unemployment on a Great Depression scale for decades, because the whole world economic system is geared around mass production and employment. It would also very possibly create global famine that would wipe out a significant fraction of the world population. The world today depends on industrial agriculture to feed itself, and high levels of production to provide the income to buy that food.

Moreover, without alternative sources of energy, even cutting economic output by half would only buy time. Yet many "degrowth advocates … oppose even 'green' megastructures like high-speed trains or industrial-scale wind farms," writes economist Giorgos Kallis. The overall objective appears to be a vague, romanticized picture of a future society based largely around pre-modern technology, but without much serious thought about how 7.8 billion people could be supported without large-scale production or farming. It simply beggars belief to think that green austerity could be politically supportable for any length of time.

An alternative climate strategy might be called "green Keynesianism," which would use a transition away from carbon energy sources to maintain full employment and high production. As economist J.W. Mason writes, even before the coronavirus struck the world economy was clearly operating well short of full capacity, and now it is in a depression. Once the pandemic passes, that idle capacity could be brought online with a gigantic green stimulus (or Green New Deal) that would quickly replace all carbon-emitting energy, transportation, manufacturing, and agriculture with zero-carbon methods in every country.

Coal and natural gas power plants will be replaced by renewables (and possibly nuclear based on safer thorium fuel, or other technologies). Oil-powered transport will be replaced by electric cars, buses, planes, ships, and bikes (with perhaps some room for carbon fuel captured out of the atmosphere). The extreme heat needed to manufacture steel and cement will be created with solar forges. Farms will slash their emissions with better land management and animal feed practices — and above all by producing much less meat, which is both horribly inefficient and a major emissions source. Deforestation will be halted across the globe, replaced by land management that will make the wilderness a net carbon sink once again.

All of those plans, especially the last one, will require substantial subsidies for developing countries to stop them from following the path of China. (Seen properly, this is not so much a handout as a way for rich countries to protect themselves and everyone else from carbon emissions outside their own borders — and it's only fair given how developed countries gained their wealth on the back of fossil fuels.) They will also require breaking the political power of the capitalist class, which profits immensely from the current filthy economy and will obstruct any green transition if it can.

The political advantage of this strategy speaks for itself. Full employment will be maintained, and rather than trying to spread out the pain of reversing 250 years of economic history, leaders will be able to spread out the benefits of increased jobs and income. The social advantages are also considerable — degrowth advocates talk a lot about how growth is alienating and socially corrosive, but not as much about how sick or disabled people will survive without advanced technology and wealth.

Make no mistake, green Keynesianism would not come without environmental costs. It would still require enormous quantities of raw materials and create considerable pollution. However, a great deal could be done to ameliorate these effects with efficiency upgrades. For instance, the insulation and climate control system in the average American home or business is grossly inefficient — but could be upgraded towards "passivehaus" ultra-low energy standards with relatively simple changes. Glass bottles could be built more sturdily and reused dozens of times. Recycling of many materials like steel, aluminum, and electronics could be drastically stepped up, and done in a clean fashion (though much plastic use, especially the cheap films used in shopping bags and packaging, will probably have to be abolished). And so on.

To give the degrowth camp their due, they are certainly correct that the current path of global capitalism is leading us straight for disaster. If nothing is done to combat climate change, we may well witness a chaotic collapse of contemporary society and a much poorer, less populated, and less sophisticated future, as happened in Western Europe after the collapse of the Roman Empire.

But it simply is not the case that there is no way to reconcile high-tech, large-scale production with climate change. All of the technologies and reforms I mentioned above are either in development, or have working prototypes, or are already being rolled out. And the coronavirus lockdowns, rather than demonstrating the need to blow up the economy to fight climate change, are better seen as proof that humanity can act quickly on a global scale to defeat a common enemy. In the socialist tradition, the way to deal with the injustice and devastating side effects of capitalism is not to abandon advanced production and wealth, but harness it on behalf of all — on a zero-carbon, renewable basis. All that is needed is the political will to enforce a drastic acceleration of what is already happening.

Want more essential commentary and analysis like this delivered straight to your inbox? Sign up for The Week's "Today's best articles" newsletter here.