climate change transport

The sources of transport emissions

A few days ago I wrote about why we need to pay more attention to transport emissions. Today I want to look at where transport emissions come from, and what the biggest challenges are. It won’t take long. Here’s a hasty graph drawn from the Committee on Climate Change figures for 2012:


For better or worse, international aviation and shipping aren’t covered by national emissions plans. They’re treated through separate agreements, such as the one on aviation negotiated this year. That doesn’t mean we can ignore it, but it does mean that the government won’t feel much obligation to act on aviation or shipping.

The bit it can focus on is domestic emissions, and it’s very obvious what the biggest problem is. So what do we mean by surface transport? Here’s how that divides up:


By some distance, the biggest source of transport emissions is cars – and I imagine that’s the main reason why transport emissions have lagged behind. People love their cars. Governments tackle car culture at their peril, fearful of that old tabloid accusation, ‘war on motorists’. But we need to get to grips with car culture. It’s contribution to climate change is too great to give it a free pass.

We know the easy answers to that – get on your bike. Take the bus. Realistically, it’s difficult to get people out of their cars in big enough numbers to make a difference. So we need better cars as well, different ways of driving, alongside desirable and efficient public transport alternatives.

HGVs and vans are worth noting on this graph too. That’s a sizeable chunk of our emissions going towards moving goods around. Since HGVs are also a major source of air pollution, that should be a priority.


  1. Two points:

    1. Less people = less transport = less emissions. And vica versa of course. Yet another reason why we have to tackle endless population growth.

    2. It is fashionable to demonise diesel cars (eg Greenpeace, parts of Government) but not HGVs, ships etc that are also diesel. Yes, they produce more NOX. But less CO2. What is the balance of harm between global warming and air pollution? It is possible to filter out diesel particulates and deal with NOX using catalysts (as modern vehicles do) but no one has found a way to filter out CO2. I will stick to using my diesel and drive it minimum distance and with small throttle openings.

    1. 1. True, but population numbers can only be reduced on a very long time frame – not fast enough to make any difference to transport emissions. We can make things easier for ourselves in future, but it can’t replace action to reduce emissions now.

      2. Yes, and I know several people who bought diesel cars thinking that it was better for climate change. Air pollution has jumped up the political agenda, and now they feel like they’re being vilified for trying to do the right thing. I’m with you on that – drive it carefully, and switch up to a hybrid or an EV when it needs replacing.

  2. Yes population reduction would take a long time but why no start now. This problem was well known in the 1960s with even Nixon saying it was a major issue. Population reduction should be at the forefront of everyone’s mind but isn’t, certainly not in the minds of politicians and economists.

    No one is thinking about their grandchildren and their progeny only about how to increase economic growth, house building, runways, power stations, landfill sites, hospital beds etc., etc., etc.

  3. Transport is required when things are in the “wrong” place and so goods and people have to be moved around.

    Better land use planning is therefore part of the solution.

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