Interested in this kind of news? Receive them directly in your inbox. Delivered once a week. Sign Up America’s coal-fired power stations have for years been the main contributor to US climate changing emissions, but with coal being phased out in favour of natural gas and renewable energy, while petrol remains cheap and freely available, transport has now taken over as the principal American contributor of greenhouse gases and air pollution. Official figures published in December show just under 1.9 billion tonnes of CO2 were emitted from transport, up nearly 2% on the previous year. Transport’s overall total has been higher, but over the period 2005-16 it has generally been around 80% of electricity generation. For the first time, electricity generation was lower at just over 1.8 billion tonnes, and its CO2 emissions are now regularly below transport for the first time since the late 1970s. Far from tackling the fact that transport now accounts for 25% of US greenhouse gas emissions, the current policy direction in Washington is to weaken emissions regulations. While Scott Pruitt, Donald Trump’s appointment as head of the US Environmental Protection Agency (EPA), has overseen the cancellation of clean truck standards, Republicans in Congress are attempting to replace state and federal limits with a single emissions standard, which environmental groups say will lead to a watering down of requirements. T&E’s clean fuels director, Greg Archer, said: ‘Leaving aside the madness of tearing up rules that limit polluting and climate-changing emissions that directly affect millions of Americans, the Trump administration’s approach is seriously bad for American business. How will US carmakers be able to compete internationally with vehicles that don’t meet standards in most of the developed world? Letting them off the hook in terms of inefficiency may help carmakers sell slightly more cars in the US, but it damages them internationally.’ Another factor in boosting transport’s emissions is that the cost of fuel in the US is significantly cheaper than in Europe and the rest of the world. Average prices for December 2017 showed a litre of unleaded petrol costing €1.31 in Europe, €0.61 in America, and €1.21 as an average for the whole world. Air quality in American cities has improved considerably over the past five decades, driven in large part by vehicle emissions standards that have progressively been tightened by the EPA. However, America’s market for large cars has lead to highly inefficient passenger vehicles. Progress was being made through fuel economy standards, but in March the EPA abandoned a deal agreed between the Obama administration and carmakers that required new cars to consume just 4.3 litres per 100km by 2025.