As promised here is the blog on diesel cars, it will be a two part blog. I believe that it is important to give you an understanding of the background on why diesel engines in cars become so popular in Europe, which this weeks blog will cover. In the next instalment I will explore in more detail the issue with diesel, the links to black carbon, and why cities now want to tax and ban diesels.
To start off I have included below a link from Top Gear from 1991 with Clarkson talking about the positives and negatives of buying a diesel car.
Clarkson predicted the future very well with this clip, even in 1991 diesel cars were billed as cleaner and better for the environment. In 1991 the market share was around 5 % for diesel cars, while in France it was over 30 %. For those who were paying attention to Clarkson it was down to lower tax and if the uk followed suit sales, would increase massively.
In 2001 this happened; lower vehicle tax for diesel cars and fuel duty was reduced as evidence suggested it was better for the environment.
Why did the drive for diesel occur in Europe ?
It was down to the Kyoto protocol which was signed in 1997. European countries had agreed to reduce greenhouse gas (GHG) emissions by an average 20 %. The transport sector was a major area where this reduction could come from by shifting from petrol cars to diesel. The IPPC Report of 2001 found that due to diesel cars being 35 % more fuel efficient it lead to a 25 % reduction in emission. Car manufacturers pushed for investment in diesel engines, leading to huge improvement in refinement and efficacy of diesel. As Europe pushed for diesel sales, as it would reduce CO2, sales started to increase dramatically. Figure 1 shows that since the Kyoto protocol sales of diesel cars boomed. In 1997 EU registrations of diesel cars was around 22 %, this was proceeded by a sharp year on year rise on the sale of diesel cars, with the only exception in 2008/9 when the financial crash happened. In 2011, EU diesel registrations made up just under 60 % of the market. It had worked, consumers had made the switch due to the promotion by governments and car manufacturers.
I remember this shift at the time, in my family we only had petrol cars until 2004, till my parents they switched to diesel. Consumers wanted a diesel powertrain it was cheaper to run, more fuel efficient and better for the environment. Sales were so good for diesel cars that many manufacturers stopped offering a petrol option all together for the European market, so you were forced into buying diesel weather you liked it or not.
Why was diesel not popular in the USA and Japan ?
Figure 1 shows US registrations of diesel cars were at 0 % until a slight increase in sales from 2008 onwards at 1or 2 % of the market. The reason for this is that diesel fuel at the pumps costs more then petrol in the USA. People regarded it as dirty fuel, and with the tax rate being 25 % higher, and emissions standards being tougher in the USA then in Europe for non - methane organic gases (NMOG) and nitrogen oxides (NOx) (which are dangerous for human health), it was therefore much harder for car manufacturers to to meet the standards In Europe there were weaker standards for nitrogen oxides in diesels compared to petrol equivalents in each series of regulations which aimed to reduce emissions, (Euro 0 to 6).
In recent years the USA tried to encouraged the sale of diesels by using ads like this Volkswagen advert that came out in 2015. Think about the relevance of this advert in light of what happened in 2015, it is quite funny how this " old wives tale" came back to haunt VW not long after - I'll explain in the next section for those who are unaware.
In the 1990s Japan's proportion of diesel cars was just under Europe's at 10%, but while that figure increased dramatically in Europe over the years due to promotion, in Japan around 1999, it was reducing, and today makes up less than 1 %. The reason was due to the Tokyo Metropolitan Government realising the impact of the high amount of particulate matter that diesels cars were producing, and in 1999 introduced the 'say no to diesel vehicles campaign'. To read more about it click this link.
Figure 1, source Cames, M & Helmers (2013).
Why are governments taking a different view on diesel cars ?
To get through tough emissions standards in the USA and in Europe, emissions standards Euro 5 came into force between 2011 to 2015. It was found in 2015 that Volkswagen cars had been using a cheat device. Here is a clip that explains it for anyone who doesn't know the story.
In the second part of the blog I will explore in detail why promoting diesel cars turned out to be such a bad decision for the environment. I will leave you with this last thought.
While CO2 is the most important greenhouse gas and was the main focus of the Kyoto protocol, it did not see black carbon emissions as a major problem. If you remember my first blog I mentioned that BC is the second most important human emission in terms of climate forcing with CO2 being the first.
Going back to the point of why diesel cars were not popular in the USA, atmospheric researchers did not regard changing to diesel cars as a good method to combat global warming, due to the high black carbon emissions that diesels produce.
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