In August last year, the Trump administration proposed the weakening of vehicle emission regulations, causing concern for climate advocates. This follows its decision to withdraw from the Paris agreement, signed in 2015, which sets specific goals to combat climate change and lower carbon emissions globally. The central aim of this agreement is to restrict global temperature increases to below 2 degrees Celsius, through nationally determined contributions from each of the 127 signatory countries. The proposal to weaken the emission regulations of vehicles is likely to be a significant setback to global efforts to lower carbon and greenhouse gas concentration, particularly because transportation accounts for 28% of emissions within the US. The lack of political acceptability of climate change policies, however, is not simply limited to the Trump administration agenda, but stems from the high cost of lowering carbon emissions, the unpopularity of a carbon tax, and lingering scepticism about climate change.
One of the tools implemented by the Paris agreement as an enabler to meet carbon emission goals is carbon pricing, which taxes companies based on their emissions. The World Bank’s report on carbon pricing for 2018 puts the total value of emission trading systems and carbon taxes at $82 billion – up from $52 billion in 2017. The public’s perception of these schemes is varied, with debate over their effect on GDP, especially in developing countries.
In addition to taxes, the cost of lowering carbon emissions is also high. Some sectors that emit substantial quantities of CO2 – such as cement and transportation – are not easily able to use sustainable alternatives. The process of carbon capture, utilisation and storage (CCUS) provides an appealing method to lower emissions from these sources by capturing the CO2 emitted before it enters the atmosphere.
A variety of technologies have arisen that aim to capture carbon emissions, many implemented at power station exhausts. This technology could also be applied to capturing vehicle and aircraft emissions (however, this is more challenging and has remained under-explored).
Following its capture, the carbon is often stored underground, but new tactics aim to use it to produce a variety of products such as fertilizer, plastics and, recently, ‘clean’ fuel. This can be seen as a circular carbon economy, where currently taxed carbon emissions can instead be captured and turned into valuable commodities.
Ethanol, for instance, which can be used as an alternative to fuels produced by the petrochemical industry, is currently produced through the fermentation of bio-feedstocks such as maize or food waste. Producing ethanol from carbon dioxide captured from vehicle or power plant exhausts holds the potential for a carbon-negative process that effectively converts carbon emissions into a valuable commodity: fuel.