A roadmap to clean living

What if we could avoid hundreds of thousand of deaths, billions of dollars in crop losses and trillions of dollars in healthcare expenditures simply by spreading off-the-shelf technology and industrialized-world regulations to developing nations? Oh, and along the way, we'd mitigate a fair bit of global warming. Sounds like a plan?

I'd say such a plan would be worth considering. Such a plan is outlined by a team led by NASA's Drew Shindell in Nature Climate Change, which has generously made their paper, "Climate, health, agricultural and economic impacts of tighter vehicle-emission standards," freely available. Here's the abstract:

Non-CO2 air pollutants from motor vehicles have traditionally been controlled to protect air quality and health, but also affect climate. We use global composition-climate modelling to examine the integrated impacts of adopting stringent European on-road vehicle-emission standards for these pollutants in 2015 in many developing countries. Relative to no extra controls, the tight standards lead to annual benefits in 2030 and beyond of 120,000-280,000 avoided premature air pollution-related deaths, 6.1-19.7 million metric tons of avoided ozone-related yield losses of major food crops, $US0.6-2.4 trillion avoided health damage and $US1.1-4.3 billion avoided agricultural damage, and mitigation of 0.20 (+0.14/â0.17)â °C of Northern Hemisphere extratropical warming during 2040-2070. Tighter vehicle-emission standards are thus extremely likely to mitigate short-term climate change in most cases, in addition to providing large improvements in human health and food security. These standards will not reduce CO2 emissions, however, which is required to mitigate long-term climate change.

The plan is pretty straightforward: tighten up on dirty emissions from diesel and to a lesser extent gasoline, and, compared with business as usual baselines, there will be significant health gains from improved air quality and agricultural output. Their will also be some decrease in the cooling effect from aerosols in the atmosphere, in the short term. But overall there will still be a small, net cooling effect thanks to decreases in other, non-CO2, greenhouse gases.

From ~30-40âyears onwards, the baseline emissions lead to warming relative to the present, especially at northern latitudes with large black carbon forcings. The tight standards lead to only a small reduction in global warming post 2040. The tight standards do, however, turn a northern Hemisphere mid-latitude warming of 0.07â°C (0.02 to 0.12)â °C into a cooling of 0.15 (0.02 to 0.26)â °C, and change an Arctic warming of 0.07 (0.01 to 0.12)â °C into a cooling of â0.21 (0.03 to â0.35)â °C over the next 50âyears.

Baseline scenario on the left, tight-emissions scenario on the left.

Convincing developing nations to embrace the emissions standards we in the industrialized world already enjoy is not the easiest thing to do, of course. (Not when there's a significant attempt to roll back our regulations by certain political forces.) But it's not the most difficult challenge facing us. And with some financial assistance, it should be feasible. The benefits will be apparent quickly, in the form of less smog to start with, and such technology transfer would lay the groundwork for the more substantial task developing nations face leapfrogging their economies past fossil-fuels into the clean renewable era to come.

We're still left with the problem of long-term climate change, which all comes back to carbon dioxide:

The emission standards examined here do not directly affect CO2, emissions of which from vehicles are projected to increase substantially. Strategies such as increased fuel efficiency, mode switching (for example truck to rail, cars to mass transit) or electrification of vehicles (powered by renewable energy) are required to reduce CO2 emissions and long-term climate change, and would complement the emission standards examined here.

Also worthy of pointing out is the challenge Shindell faced when trying to find support for this research. In an interview with Nature, he complains about being turned down at first because the project focused on the human impacts of pollution.

I had a grant proposal for this project rejected on the basis that although it was great for understanding societal impacts and understanding benefits, it didn't show enough new understanding of fundamental atmospheric science. So, I would advise people to think about who is going to pay for the research.

Somebody did come forward with the funding eventually. But it is sad to discover that at this juncture, when there is no real doubt about whether burning fossil fuels is a bad idea, every relevant funding agency isn't enthusiastic about supporting research into the consequences.

And a final note: Shindell is also responsible for the recent (2009) recalculation of the global warming potential of methane, research that found its way into the controversial paper by Howarth et al. so many natural-gas proponents have been complaining about -- the one that says fugitive emission from fracked gas wells could mean that gas is worse than coal when it comes to global warming. Hopefully this new paper will be received more warmly. It's a remarkably accessible piece of scientific literature, to boot. Highly recommended.
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Shindell, D., Faluvegi, G., Walsh, M., Anenberg, S., Van Dingenen, R., Muller, N., Austin, J., Koch, D., & Milly, G. (2011). Climate, health, agricultural and economic impacts of tighter vehicle-emission standards Nature Climate Change, 1 (1), 59-66 DOI: 10.1038/nclimate1066