To assess the effectiveness of climate policies, don’t look at today’s CO₂ emissions, instead focus on the trajectory.
Read the full Risky Climate column at Bloomberg Green.
Levels of CO₂ in the atmosphere were higher in 2020 than in any year in human history. They will be higher in 2021, reaching 50% above pre-industrial levels for the first time. Concentrations will be higher still in 2022, 2030, and will likely continue to grow for the better part of the century.
Climate change is a bathtub problem. Global average temperatures, sea levels and other climatic effects from floods to droughts are intimately linked to the CO₂ already in the atmospheric tub. It’s not sufficient to stabilize the flow of CO₂ going into the tub when the goal is to prevent it from overflowing. That means turning off the flow of water into the tub—getting net emissions to zero and below. It is why serious net-zero emissions targets are so important.
The emphasis here is on “serious.” The U.K.’s 2008 Climate Change Act established a goal of decreasing the country’s net emissions by 80% below 1990 levels by 2050. That alone was ambitious. In 2019, the British parliament passed a fateful amendment. It simply read: “for ‘80%’ substitute ‘100%’.” Of course, getting there is not as simple.
Long-term goals can easily be misconstrued as cheap talk, if they aren’t followed by near-term action. And 2050 isn’t all that “long-term” to begin with. Almost any infrastructure project or other investment planned today will still stand well into the second half of the century. Homes built today and financed with a 30-year mortgage will still be partially owned by the bank by the time they, too, need to fit under the net-zero umbrella.
The importance of near-term action makes it tempting to revert to annual CO₂ emissions as a metric for how well a country, company, or the world, is doing on meeting net-zero goals. That would be a mistake. Of course, annual net CO₂ emissions are intimately tied to the stock of CO₂ already in the atmosphere. But focusing on emissions alone opens up too many other variables to be useful.
For one, there is the all-too human dimension.
Continue reading at Bloomberg Green.