2 . Aviation is a big polluter. Cutting the sector’s impact on global warming is high on the agenda. Although many governments are regulating emissions from cars and trucks, air transportation is technologically rooted in old patterns.

Facing the reality that the sector will keep emitting a lot, ICAO has established an international carbon-trading plan—Carbon Offsetting and Reduction Scheme for International Aviation, or CORSIA. This encourages wide use of offsets (抵消) : aviation companies can buy emissions credits or invest in sectors that store carbon, such as forestry, to allow them to carry on as normal. CORSIA aims to keep CO2 emissions at 2019 levels through such purchases for emissions over that year’s baseline. ICAO predicts that increasing demand might reach 1. 7 billion tons by 2035, potentially making aviation the largest offset market in the world.

Yet offsetting faces a fundamental challenge: the size of the offset requires estimating flows of warming pollution that would have occurred if the carbon-removal project hadn’t existed, and comparing them against flows with the project in place. The former — a baseline that is unobservable — is a hotbed for shady accounting.

The vast majority of offsets today and in the expected future come from forest-protection and regrowth projects. The track record of reliable accounting in these industries is poor, because they lack convincing baselines. Even with oversight, forest projects are often troubled by wild assumptions, for example that trees would disappear completely from these areas in the absence of those projects, even when there are other forest protections in place. Such assumptions drive up baselines and flood the market with huge volumes of offsets. They make it easier for accountants to claim a net reduction in emissions even though the atmosphere sees little or no benefit. These problems are essentially unfixable. Evidence is mounting that offsetting as a strategy for reaching net zero is a dead end.

In our view, this approach could prove dangerously narrow. Removing aviation’s impact on global warming means upending the industry. The longer that reality is overlooked, the harder it will be to find effective solutions.

3 . “Reduce, reuse, and recycle”, this familiar environmentalist slogan tells us how to reduce the amount of rubbish that ends up in landfills and waterways. The concept is being used to deal with one possibly dangerous form of waste — electronic junk (电子垃圾), such as old computers, cell phones, and televisions. But this process for managing e-waste may be used in an unscrupulous (肆无忌惮的) way more often than not used, a recent report suggests.

“A lot of these materials are being sent to developing nations under the excuse of reuse — to bridge the digital divide (消除数字鸿沟),” said Richard Gutierrez, a policy researcher.

One of the problems is that no one proves whether these old machines work before they hit the seaways. Because of this, the report says, e-waste is a growing problem in Lagos, Nigeria, and elsewhere in the developing world. Much of the waste ends up being thrown away along rivers and roads. Often it’s picked apart by poor people, who may face dangerous exposure to poisonous chemicals in the equipment.

Businessmen also pay workers a little money to get back materials such as gold and copper. This low-tech recovery process could expose workers and the local environment to many dangerous materials used to build electronics. According to Gutierrez, this shadow economy exists because the excuse of recycling and reusing electronics gives businessmen “a green passport” to ship waste around the globe. “Developing nations must take upon some of the responsibility themselves,” Gutierrez said. But, he added, “A greater portion of this responsibility should fall on the exporting state (出口国).”

China, for example, has become a dumping place for large amounts of e-waste. The nation is beginning to take action to stop the flow of dangerous materials across its borders. The Chinese government, after many years of denial (拒绝) is finally beginning to take the lead.