US President Donald Trump has announced the reversal of the so-called endangerment finding, a key Obama-era scientific ruling that underpins much of US environmental legislation. As a result of this, experts are predicting various environmental and economic impacts, though the decision by the US Environmental Protection Agency (EPA) is expected to be challenged in the courts from environmental groups.

Here are some of the potential impacts.

### Fewer greenhouse gas emissions restrictions
The most obvious outcome of the legislative change is that there will be fewer restrictions placed on greenhouse-gas-producing industries - in particular vehicle manufacturers. The 2009 endangerment finding stemmed from a major report by the EPA identifying greenhouse gases as endangering current and future generations. Its removal could result in an additional 7.5 to 18 billion tonnes of emissions by 2055, according to estimates, leading to potential costs running into the trillions of dollars.

### Cheaper cars in the US (but harder to export)
Despite backlash from environmental groups, the Trump administration claims economic benefits from the repeal, particularly in terms of vehicle production costs which are expected to decrease by about $2,400 per car. However, it raises concerns about US competitiveness in the global market as other nations continue to embrace stricter emissions standards.

### Nuisance lawsuits
The reversal means that US companies might face an increase in public nuisance lawsuits related to environmental harm, disrupting the legal landscape in pollution regulation.

### Public health
Scientists warn that the increased emissions could predictably lead to health complications, with projections indicating thousands of additional premature deaths and asthma attacks.

### Falling behind in the global renewables race
This announcement calls into question America's future in the renewable energy sector. While electric vehicle standards are relaxed domestically, international competitors are accelerating their renewable technologies, which could leave US automakers lagging.

### Less industry regulation
The Trump administration defends the rollback as a crucial step in reducing unnecessary regulation, purportedly saving American taxpayers substantial sums while promising to restore jobs that may have moved to countries with less stringent environmental policies.

In conclusion, the implications of Trump's policy reversal are extensive, potentially altering the landscape of American environmental policy, public health, and international competitiveness in renewable energy.