for all With less encouraging news about climate change — sea levels are rising rapidly, the land itself is changing, serious trouble is brewing under Antarctic glaciers — we’ve been hopeful. For example, the price of renewable energy is plummeting, and we are moving towards a cleaner, electrified future faster than you can imagine.
The shift is evident in a near-inspiring paper published today in the journal nature: Modelling by an international team of scientists suggests that humans could keep temperatures below 2°C above pre-industrial levels if countries stick to their recent climate commitments, including those made at COP26, the Paris Agreement goals outlined in . It’s not below the 1.5-degree threshold we really want (the more optimistic target in the agreement), but it’s a far cry from the extreme warming of 3, 4, or even 5 degrees previously predicted by the agreement. This will only happen if countries deliver on their promises to rapidly decarbonize their economies – which is not guaranteed.
“Those very high emissions trajectories that people used to talk about look unlikely today,” said Christopher McGride, head of the IEA’s energy supply unit and co-author of the new paper. “This is good news because it shows the progress the world has made in terms of policy and technology over the past few years.”
To achieve an optimistic scenario of less than 2 degrees of warming, McGride and his colleagues scrutinized climate commitments made by nearly 200 countries between the Paris Agreement signed in 2015 and the conclusion of COP26 last November. . These are called “net zero” commitments. The United States, for example, has pledged to achieve net-zero emissions by 2050, which means it will put as much carbon into the atmosphere as it has emitted by then. This is a rather tricky concept because a country can continue to emit greenhouse gases as long as it also uses carbon removal technologies to sequester them. These exist, but are nowhere near the scale needed to reduce atmospheric carbon concentrations. Countries can (and should) strengthen ecosystems to naturally sequester carbon as plants grow, thereby offsetting emissions.
The researchers used all of these commitments to estimate future global emissions, which they then plugged into a climate model that calculated a temperature increase of less than 2 degrees by 2100. (For reference, we’re already at about 1.2 degrees above) pre-industrial levels. ) “It shows that if the government delivers on what they say is its net zero commitment, it will be the first time we have limited warming to below 2 degrees Celsius,” McGride said. “Before COP26, there was never enough policy commitment or enough policy momentum to limit warming to below 2 degrees.”
Beyond that political movement, several trends are converging to make this progress possible. On the one hand, the cost of solar and wind power, as well as lithium-ion batteries used to store electricity, fell by as much as 85 percent between 2010 and 2019, according to the latest report from the United Nations Intergovernmental Panel on Climate Change. “This is really, really impressive, and it’s one of the key reasons why we actually got this result in the paper,” McGlade said. “In many cases, it is cheaper to deploy a new wind farm or a new solar farm than to deploy a new coal-fired power plant. This is the case in many, many places in the world today.”