The average global temperature today is about 1°C higher than it was before the Industrial Revolution began in the late 1700s. That may not sound like much, but scientists agree that just one more 1°C, and our planet will pass a tipping point beyond which there could be irreversible changes to the global climate that wreck worldwide havoc.
It sounds terrifying, and it is. Which is why it may surprise you to read that the climate-change problem is, in a way, quite straightforward. The Earth’s atmosphere is trapping too much of sun’s heat, because we’re adding ever-growing amounts of greenhouse gases into the atmosphere through burning fossil fuels for energy. To solve the problem, we can do two things: find ways to reflect sun’s heat (solar-radiation management) or reduce our greenhouse-gas emissions (carbon management).
Solar-radiation management was first proposed in the 1970s, and there are many ways to achieve the end goal. The most well-studied proposition is injecting fine sulfur particles into the stratosphere, a region of the atmosphere starting at about 15km (9 miles) above the surface of the Earth. In theory, it would create a haze across the world’s skies and cut the amount of solar heat entering the atmosphere. It would be cheap to deploy, costing about $8 billion per year, according to one estimate.
But we have a very poor understanding of the local effects of dialing down solar radiation. Even the strongest advocates for the sulfur particle-based technology say a lot more research is needed. The Earth’s many natural cycles—water, carbon, and nitrogen, for example—would suddenly be disrupted. Rain patterns could change drastically. Agricultural productivity could dip. The chemical reactions between ozone and sulfur might cause the ozone layer to start rapidly depleting, which could be a serious threat to life on the planet.
We’d need a global consensus before trying the experiment. Considering how difficult it was to reach a consensus for a weak Paris climate agreement with voluntary goals, it’d be nearly impossible to come to an agreement on a geoengineering project with so many uncertainties associated—and with so many potential regional impacts. (Recommended reading: This Q&A with Oliver Morton, author of Planet Remade: How Geoengineering Could Change the World.)
Realistically, then, geoengineering isn’t an option yet. Which leaves us with carbon management. There isn’t much uncertainty about what would happen if we stopped putting so much carbon dioxide in the atmosphere: the rate of globally temperature rise is likely to slow, which could avert many of the predicted climate-change catastrophes. The difficulty is finding ways to cut greenhouse-gas emissions quickly without sinking the global economy.
Right now, most of our emission-reduction efforts are focused on burning fewer fossil fuels: scaling up solar and wind power, getting more electric vehicles on the road, improving energy efficiency (such as LED lights and better heat insulation), funding underdeveloped green energy sources (such as geothermal and tidal power), and promoting the use of emissions-free hydrogen as a fuel.
But the impact of all that has so far been miniscule. We still get more than 80% of all our energy from burning fossil fuels—the same percentage as we did back in the 1970s. Something has been missing from our attempt to solve the biggest problem humanity has faced.
We scienced our way into this problem. Can we science our way out?
The missing solution is carbon-capture technology, which allows us to keep burning fossil fuels without putting greenhouse gasses into the atmosphere. It’s a rapidly improving science that could provide a bridge to a future in which we’ll have enough capacity to create, store, and supply all the world’s energy from only renewable sources.
My gut reaction to carbon capture when I first heard about it was that it seemed like a bad idea to invest in a technology that keeps fossil fuels alive when our eventual goal is to move away from them. If this is the first time you’ve read about these technologies, you may feel the same way. But, counterintuitively, paying fossil-fuel companies and other carbon-emitting industries in the short term is exactly what we need to do. Study after study show that the only way we can reach zero emissions without torpedoing the global economy is by investing in carbon-capture technologies.