False: “Cars are related to pollution, but have nothing to do with climate change”

Former Barcelona mayor Xavier Trias stated in an interview that “cars are related to pollution, but have nothing to do with climate change”. He added that “we should not mix concepts, since then good-faith people end up joining battles which are not connected”. After analyzing different scientific reports, the claim turns out to be false. 

Contextual analysis: the May 28 Spanish local elections

On May 28, 2023, local elections were held in all Spanish municipalities. Over the past months, contenders for the mayoral post have been involved in an intense election campaign, especially in big cities such as Barcelona. In the Catalan capital, the current mayor, the left-wing Ada Colau, stands for re-election after having been chosen again as Barcelona en Comú candidate. Over the last eight years, Colau has placed an emphasis on climate change and has driven some environmental reforms, such as the implementation of the Low Emission Zone (LEZ), a protected area of over 95 square kilometres where vehicles without an environmental label can not circulate. 

In this sense, the conservative nationalist Xavier Trias, who was Barcelona mayor between 2011 and 2015 and now runs as Junts per Catalunya candidate for the mayoral post, stated that “cars are related to pollution, but have nothing to do with climate change”. This claim was recorded during an interview organized by the digital newspaper Línia on March 27. In minute 13:19, Trias stated: “Everyone who thinks cars have to do with climate change is mistaken; we should not mix concepts, since then good-faith people end up joining battles which are not connected”, he said. Right after, he claimed that “what [Barcelona] should do is to reduce pollution, and electric cars must be a priority, so that we remove cars which use harmful fuels”. 

In response to this statement, Colau branded Trias as a “climate change denier”, and Esquerra Republicana’s second candidate for the mayoral post, Elisenda Alamany, tweeted that “Trias imagines a Barcelona that does not exist anymore, in which causes of climate change were questioned”. 

Scientific analysis: greenhouse gas emissions from road transport

There is consensus among the main international environmental institutions that cars produce greenhouse gas (GHG) emissions. As stated in the Intergovernmental Panel on Climate Change Sixth Assessment Report (2023), in 2019 15% of the global GHG emissions came from transport. According to the European Environment Agency, nowadays transport represents around 25% of the EU’s total GHG emissions, of which 71.7% came from road transport in 2019.

Source: European Parliament

In addition, transport is the only major economic sector where GHG emissions have increased in the past three decades. Even though most car manufacturers in EU, Iceland, Norway and the United Kingdom met their annual binding targets in 2020, that year petrol cars were still the most sold type of new passenger cars. 

Carbon dioxide (CO2) is the GHG which most affects climate change, that is, the increase in global temperatures. In 1956, a group of American scientists analyzed the possible effects of an increase in atmospheric carbon dioxide, and they already related CO2 to fossil fuels. As exposed by IPCC, “CO2 emissions from fossil fuel combustion and industrial processes contributed about 78% of the total GHG emission increase from 1970 to 2010, with a similar percentage contribution for the period 2000-2010”. According to the International Energy Agency, “global energy-related CO2 emissions grew by 0.9% in 2022, reaching a new high of over 36.8 gigatons (Gt)”. According to the IPCC (quoted by United States Environmental Protection Agency, 2014), “fossil fuel use is the primary source of CO2”. However, cars also produce small quantities of other GHG, such as methane (CH4), nitrous oxide (N2O) and fluorinated gases (F-gases).

Cars also produce air pollutants, such as particulate matter (PM) and nitrogen dioxide (NO2), which do not contribute to the greenhouse effect but harm human health and air quality. The aforementioned Low Emission Zone in Barcelona is precisely created to reduce these air pollutants, as explained in the report ‘Barcelona: Benefits of the Low Emission Zone’ by C40 Cities Climate Leadership Group.

Xavier Trias’ claim versus some EU recent news

Trias’ claim coincided with some important environmental reforms and warnings on an international and European level. In March 20, 2023, the IPCC published a report in which scientists warned that “urgent climate action can secure a liveable future for all”. Among other issues, they exposed that “changes in […] transport […] can reduce greenhouse gas emissions”. Last February, the European Parliament approved a ban on the sale of new petrol and diesel cars from 2035, which means that all cars will need to be CO2-neutral, in relation to the EU climate neutrality goal by 2050. 

Conclusion

As we have seen through some environmental reports, it is not true that “cars have nothing to do with climate change”, because fossil fuel use is the primary source of CO2, the GHG which most contributes to global warming. In addition, cars produce other greenhouse gases, such as methane (CH4), nitrous oxide (N2O) and fluorinated gases (F-gases), that are also related to climate change. 

Read more about how we analysed Xavier Trias’ claim about cars and climate change in our Behind the Facts blogpost.

RESEARCH | ARTICLE © Berta Coll i Bosch. Universitat Pompeu Fabra.