Environmentalists’ worst fears were realised yesterday when former Oklahoma attorney general Scott Pruitt was sworn in as head of the US Environmental Protection Agency.

Describing him, at best, as a climate change sceptic and, at worst, an “unqualified extremist”, environmental groups fear he will overturn or loosen many hard-won regulations, in particular efforts to reduce greenhouse gas emissions.

So what is the future for US involvement in the Kigali agreement and the global efforts to phase-down HFC refrigerants under the Montreal Protocol?

During his election campaign and since, Trump has never mentioned the Kigali amendment or the HFC phase down. Pruitt, himself, has disagreed with Donald Trump’s claim that climate change was a hoax, but he has questioned whether it was effected by human actions.

During his confirmation hearing in January, when specifically asked whether as EPA administrator he would work with all stakeholders and the State Department to execute the Kigali amendment, Pruitt confirmed that he would “work with all involved agencies and impacted stakeholders to ensure that EPA’s actions related to hydrofluorocarbons are coordinated accordingly.”

The Kigali amendment will still need to be ratified by the Republican-led US Senate but it seems unlikely that the Trump administration will act against the wishes of US industry which has unanimously joined with environmental groups in backing an HFC phase down.

The refrigerant manufacturers Honeywell and Chemours have invested millions in developing lower GWP alternatives and leading refrigeration and air conditioning equipment manufacturers like Trane, Carrier and Emerson, have, likewise, financially backed their incorporation in new products.

Whether the US, a huge influence in achieving the Kigali amendment, continues to lead the issue at an international level is open to debate, but any softening of US commitment is now unlikely to have any effect on the commitments already made by other countries.

In any event, US manufacturers will not isolate themselves from the global market. Their lower GWP products will be in great demand as the rest of the world moves towards more efficient, environmentally-acceptable alternatives.

And will the USA be content to see itself out-paced, technologically, by the so-called developing countries?