Net zero by 2050

陈小将

First, it's vital that we limit further temperature rises to less than 1.5 C to 2 C. Delivering on that by 2050 requires cutting emissions by 25-50 percent by 2030 compared to pre-2019 levels.
The good news is that about 140 countries — accounting for 91 percent of greenhouse gas emissions — have already proposed or set net-zero targets for around mid-century. The bad news is that net-zero rhetoric does not match reality.
But getting to net zero by 2050 means most countries need to do even more to strengthen their targets for cutting emissions — particularly large economies. Also, there is an even bigger gap on the policy front. A new analysis of current global climate policies by the International Monetary Fund shows they would only deliver an 11 percent cut. The gap between that and where we need to be is massive — equivalent to more than five times the current annual emissions of the European Union.
We desperately need implementation to catch up. That will require a mix of incentives to push enterprises and households to prioritize clean goods and technologies across all their decisions.
The ideal policy mix would include pricing carbon, including cutting fossil fuel subsidies, along with alternative measures that can achieve equivalent outcomes, such as fee-bates and regulations. To complement domestic policies, an international carbon price floor agreement would provide one way of galvanizing action: asking large emitters to pay a minimum price of $25-$75 per ton of carbon depending on their national income level. Alternative policies do not mean taxes per se. It would be collaborative, pragmatic, and equitable.
Of course, the overall policy package should also include measures to reduce methane emissions. Cutting these emissions by half over the next decade would prevent an estimated 0.3 degree rise in the average global temperature by 2040 — and help avoid tipping points.
It is also critical to include incentives for private investments in low-carbon technologies, growth-friendly public investments in green infrastructure, and support for vulnerable households.
The new IMF analysis has encouraging projections for an equitable package that would contain global warming to below 2 C. We estimate that the net cost of moving to clean technology — including the savings made by avoiding unnecessary investments in fossil fuels — would be around 0.5 percent of global gross domestic product in 2030. This is a tiny amount compared with the devastating costs of unchecked climate change.
But the longer we wait, making the shift would be far more costly and more disruptive.