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Reliance on Technical Solutions to Environmental Problems: Caution Is Needed Patrick Moriarty* Department of Design, Monash University-Caulfield Campus, P.O. Box 197, Caulfield East, Victoria 3145, Australia
Damon Honnery* Department of Mechanical and Aerospace Engineering, Monash University, Building 31, Victoria 3800, Australia auxiliaries such as air-conditioning, information and entertainment systems, and power steering.1 National transport oil use and CO2 emissions are also subject to the well-known rebound ef fect: vehicle efficiency improvements make travel cheaper per kilometer, encouraging more travel. Furthermore, most of the world’s population aspire to the car ownership levels of the OECD countries, so total transport oil use and CO2 emissions are still growing. This rebound effect is not the fault of the technology, but of our use of it. There is yet another reason for caution: technical advances are sometimes reversed as more information about unwanted effects accumulate. Such has been the case for leaded petrol. More recently, France is considering reversing its previous promotion of diesel-fueled cars. Although diesel cars are more efficient than petrol cars, concern is mounting over the health effects of diesel’s fine particulate releases. As another example, novel chemical compounds such as chlorofluorocarbons, once though as environmentally benign (having low reactivity, toxicity and boiling point), were later found to cause ozone layer depletion. We need to be especially cautious when dealing with global he world is full of examples of unintended consequences. problems such as climate change. One important approach for Many solutions to burgeoning problems, whether social climate change mitigation is reducing fossil fuel use through or technological, are later found to have unintended side effects. much greater use of renewable energy, particularly biomass. But Sometimes these are beneficial; more commonly, they are not, a recent study2 found that increasing forest plantation area, and can be serious enough to call into question the efficacy of whether for carbon fixation in newly planted forests or the original solution. One key area for concern is with bioenergy harvesting, runs the risk of decreasing Earth’s overall technological solutions to our many environmental challenges. albedo (the fraction of insolation reflected directly back into Car travel exemplifies the mixed success of technological space.) In short, such plantations would store carbon, and/or solutions to the environmental problems it generates. At least reduce CO2 emissions from fossil fuels, but at the same time in the cities of the Organization for Economic Cooperation and would absorb more solar energy, at least partly offsetting the Development (OECD) countries, urban air pollution from intended climate mitigation effect. vehicles has been greatly reduced over the past half-century. There are further problems with reliance on biomass for Technical emission reduction innovations include unleaded climate mitigation. Depending on which items are included, petrol, progressively lower sulfur content fuels, and three-way humans may already appropriate up to half of Earth’s Net catalytic converters. But other proposed innovations for solving Primary Production3 to meet their still-growing needs for food, fiber, timber, and forage for farm animals. If the large increases both global oil depletion and climate change may fall short of in bioenergy forecast by the IPCC are realized, bioenergy will their stated aims. Improving the fuel efficiency of all vehicles be competing for land and water with these existing usesor promises to cut both transport oil use and accompanying with natural forests, especially in the tropics. One consequence greenhouse gas emissions. However, although vehicle engine will be a rise in food prices. Increased use of corn for ethanol efficiency has made large gains, the on-road vehicle efficiency gains (in terms of vehicle-km per MJ) have been much more modest. Reasons include preferences for larger or higherReceived: March 10, 2015 Published: April 24, 2015 performance vehicles, and significant power requirements for
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© 2015 American Chemical Society
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DOI: 10.1021/acs.est.5b01235 Environ. Sci. Technol. 2015, 49, 5255−5256
Viewpoint
Environmental Science & Technology
(3) Moriarty, P.; Honnery, D. What is the global potential for renewable energy? Renewable Sustainable Energy Rev. 2012, 16, 244− 252. (4) IPCC. Climate Change 2014: Synthesis Report; Cambridge University Press: Cambridge, UK, 2015. (5) Steffen, W.; Richardson, K.; Rockström, J.; Cornell, S. E.; Fetzer, I.; Bennett, E. M.; et al. Planetary boundaries: Guiding human development on a changing planet. Science 2015, 347 (6223), 1259855 (10pp).
production has already caused global corn prices to spike on occasion. Another ambitious proposal for mitigating climate change is geoengineering, discussed for the first time (but not included in any scenarios) by the IPCC in its latest report.4 The most popular approach considered is the annual injection of millions of tonnes of sulfate aerosols into the lower stratosphere. If feasible, Earth’s albedo would be enhanced, and average global temperatures would fall in a matter of months. Since the atmospheric lifetime of aerosols is limited, geoengineering could be quickly terminated if unanticipated problems were found. But it is already known that aerosol injection will lower global precipitation, a serious drawback in an already watershort world. And it offers no solution to the other CO2 problem: the progressive acidification of the world’s oceans, which could adversely affect ocean ecosystems. Further, geoengineering runs the risk of introducing Earth system changes of which we are currently unaware. What explains the diminishing effectiveness of technically based solutions for many of today’s most pressing environmental challenges? Steffen and colleagues4 warn that the Earth is now approaching nine planetary boundaries or thresholds in the Earth system. For several of them, including the two core boundaries of climate change and biosphere integrity, the ‘safe operating space for humanity’ has already been exceeded. Passing any of these thresholds could lead to dangerous environmental changes. So an apparent technical solution to one problem, such as geoengineering to limit rises in average Earth surface temperature, could cause other planetary limits, such as for fresh water use or ocean acidification, to be approached. Fortunately, the need for Earth Systems thinking when analyzing the effects of new technologically based innovations is increasingly recognized by researchers and policy makers. A variety of overlapping approaches are increasingly used, including green chemistry, green design, design for the environment, industrial ecology, and life cycle analysis. But these alone, while vital in pinpointing possible conflicts between different environmental objectives, do not go far enough. For global problems such as climate change, and declining availability of fresh water, fossil fuels and high-grade mineral ores, conservation solutions will need to be given at least equal importance with these “green” solutions.5 There is evidence of some shift in official thinking here as well: compared to its four earlier reports, the latest IPCC report4 places far more emphasis on such nontechnical solutions to climate change problems.
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AUTHOR INFORMATION
Corresponding Authors
*E-mail:
[email protected]. *E-mail:
[email protected]. Notes
The authors declare no competing financial interest.
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REFERENCES
(1) Moriarty, P.; Honnery, D. Greening passenger transport: A review. J. Clean. Prod. 2013, 54, 14−22. (2) Keller, D. P.; Feng, E. Y.; Oschlies, A. Potential climate engineering effectiveness and side effects during a high carbon dioxideemission scenario. Nat. Commun. 2014, 5 DOI: 10.1038/ ncomms4304. 5256
DOI: 10.1021/acs.est.5b01235 Environ. Sci. Technol. 2015, 49, 5255−5256
