内容来源:  华夏气候

The global climate implications of the US election

If Biden – or another Democrat – wins the election in November and if his party regains control over the House and Senate, then they could push to implement new climate policies in 2025.

There is a clear need for further policy, if US climate goals are to be met. Moreover, the expiration of a large number of tax cuts at the end of 2025 could present an opportunity to deploy carbon pricing in support of raising revenues – and cutting emissions – according to a recent study.

It suggests that a price on emissions, described as a “carbon fee”, could significantly boost US chances of hitting its 2030 target, even if paired with a partial repeal of the IRA.

(Note that the “Repeal IRA; no new emissions rules” scenario in this study is similar to the “Trump” scenario in Carbon Brief’s analysis. However, the model used in the study finds a relatively weak 2030 emissions impact of the IRA compared with most of the five others, with which it is aggregated by Carbon Brief.)

An additional point of leverage is the EU’s carbon border adjustment mechanism (CBAM), which will put a carbon price on US exports unless they face an equivalent price domestically, according to Democratic senator Sheldon Whitehouse, speaking at a launch event for the study:

“The 2025 opportunity when the Trump tax cuts collapse [creates] huge room for negotiation. Then you’ve got the CBAM happening in Europe that puts enormous pressure to get a price of carbon, if you want to avoid being tariffed at the EU and UK level.”

Whether a second-term Biden administration would attempt to put a price on carbon or not, it would be likely to push forward new policies in pursuit of US climate targets.

In contrast, a victory for Donald Trump could be expected, at a minimum, to result in full or partial repeal of the IRA and rollbacks of Biden’s climate rules, including power plants, cars and methane.

This is reflected in Carbon Brief’s “Trump” scenario, which would add a cumulative 4GtCO2e to US emissions by 2030, as shown in the figure below.

Moreover, assuming no further policy changes, this cumulative total would continue to climb beyond 2030, reaching 15GtCO2e by 2040 and a huge 27GtCO2e by 2050.

Cumulative increase in US emissions, GtCO2e, under the “Trump” scenario relative to the “Biden” scenario, assuming no further policy changes beyond rolling back the IRA and key Biden administration climate rules. The range corresponds to results from six different models and uncertainty around economic growth, as well as the costs for low-carbon technologies and fossil fuels. Source: Carbon Brief analysis of modelling in Bistline et al. (2023) and Rhodium Group (Taking stock 2023). Chart by Carbon Brief.

The increases in cumulative emissions under the “Trump” scenario are so large that they would imperil not only the US climate targets, but also global climate goals. (Under the 22nd amendment of the US constitution, Trump would not be allowed to run for a third term.)

In 2022, the Intergovernmental Panel on Climate Change (IPCC) sixth assessment report (AR6) said that it would be “impossible” to stay below 1.5C without strengthening current pledges:

“[F]ollowing current NDCs until 2030…[would make] it impossible to limit warming to 1.5C with no or limited overshoot and strongly increas[e] the challenge to likely limit warming to 2C.”

The corollary of this is that if the US – the world’s second-largest emitter – misses its 2030 target by a wide margin, then it would be likely to end any hope of keeping global warming below 1.5C.

内容来源:  国际能源小数据 财联社