Dozens of countries have pledged to cut their net planet-warming pollution to zero by the middle of the century — but most have no idea how hard they’ll need to work to get there. That’s risky, writes Chelsea Harvey, because any greenhouse gas pollution that countries fail to eliminate at the source will need to be sucked out of the air afterward — a technological feat that’s far from being deployed on a large scale. Or countries will need to “offset” that pollution by buying credits from other countries. Yet the vast majority of countries haven’t even offered an estimate of how much of this leftover pollution they will have to deal with. Right now, the world’s largest direct air capture plant is capable of removing less than 1 percent of the annual emissions of a typical coal-fired power plant. And the technology’s prospects face other obstacles, such as competition for land use. Countries that have done the math expect to remove or offset anywhere from 5 percent to a whopping 52 percent of their peak greenhouse gas emissions by 2050, according to a new study. Some of those estimates are likely low. That’s because they omit the likeliest suspects for continued carbon pollution: aviation and shipping, two sectors whose greenhouse gas emissions are widely expected to be hard to cut. Experts say world leaders should try to eliminate atmospheric pollution as much as possible by producing less of it on the front end, leaving less carbon to pull out of the air after the fact. But only 72 of the 195 countries that ratified the Paris Agreement have submitted voluntary long-term strategies for achieving a low-carbon economy by midcentury. Of those, a mere 26 included an estimate of what their remaining emissions will be. (The United Kingdom and the European Union have submitted “acceptable” net-zero strategies, while the United States’ was merely “average,” according to one scientific group that rates countries’ targets.) Most wealthy countries predicted their leftover pollution will be between 5 and 15 percent by 2050. But not all. Canada presented a range of possible future scenarios, including residual pollution totaling anywhere from 17 to 44 percent of the country’s peak emissions. Australia’s scenarios range from 36 to 52 percent. Those high ranges indicate that some countries don’t necessarily plan to switch away from oil, coal and natural gas. Canada’s long-term plan makes that explicit: “[F]ossil fuel production and consumption could remain higher,” it says, if carbon removal technologies become viable at large scales.
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