Which Policy to Address Climate Change?
IPN Opinion article
International Affairs Forum
When considering the best policy to address climate change, it seems reasonable to begin by asking what impact climate change is likely to have. Southgate and Songhen (2007) looked at how food production and forestry have changed in the past hundred years and how they might change in the coming century in response to a one to four degree Celsius rise in global mean temperature. After showing that the past hundred years have seen a dramatic rise in productivity in both agriculture and forestry, they conclude that the impact of even a four degree Celsius rise in temperature is unlikely to reduce productivity considerably. The reason is simple: as long as individuals and companies continue to be able to make investments in the development of new technologies, agricultural and forestry productivity will continue to outpace population growth. There may be some changes in the value of land in different parts of the world, but the net effect of climate change is likely to be small compared to the net effect of technological change.
One caveat is worth making, however: there are barriers to adaptation, most of which come from government intervention of one kind or another. For example, government ownership of land and water lead to perverse, inefficient, and often environmentally less suitable uses. When land and water are owned privately, the owners have incentives to put those resources to their highest-valued use; that often means applying effective conservation measures, using water efficiently, creating fire breaks in forests, and so on. Government regulations on land uses often have a similarly detrimental impact, since they preclude many private sector innovations. Likewise, government subsidies often have perverse consequences, such as encouraging the production of crops unsuitable to the terrain and over-abstraction of water. Southgate and Songhen argue that adaptation will take place most rapidly and at least cost if government gets out of the way.
Reiter (2007) analysed the supposed impacts of climate change on health. He found that, contrary to claims made by others, rates of malaria have not risen as a result of climate change. Rather, in wealthy countries, malaria rates have declined dramatically as a result of a combination of, inter alia, changes in animal husbandry practices (people no longer live close to animals), drainage of swamps (where mosquitoes breed), the use of insecticides and larvicides, and the use of air conditioning. Meanwhile, in poorer countries, malaria rates declined after about 1960, in large part as a result of using DDT and other insecticides, but are now rising again, in large part because of reduced usage of DDT.
Other health impacts are also highly dependent on wealth, with people in richer countries generally being far less susceptible to death as a result of extreme temperatures than people in poor countries (Keatinge, 2004). Thus, an increase in wealth will by itself likely reduce the rate of mortality from extreme temperatures because people will be better able to afford clean and efficient heating and cooling systems, as well as having greater access to medical facilities. But increased wealth also brings the capacity to invest in other strategic disease-reducing activities, such as more effective preventive measures for vector-borne diseases.
Notwithstanding the importance of enabling wealth generation, there are other measures which if taken now and over the course of the next few decades will dramatically reduce the likelihood that any AGW would cause an increase in mortality. Those measures include expanding programmes that have been demonstrated to reduce the incidence of diseases such as malaria. For example, spraying the inside walls of huts with small quantities of DDT has been shown to reduce malaria without adversely impacting human health or the environment (Attaran et al, 2000).
Goklany (2007) shows that mortality and mortality rates from weather-related natural disasters have declined dramatically over the past century. The reasons for this are many and varied but include increased wealth, better building materials, and more reliable warning systems. While the economic damage done by such events has risen, the main reason for this is that wealth has increased both in aggregate and on average. Goklany shows that as a proportion of total wealth in the US, the impact of extreme weather events has remained largely constant over the past century.
In sum, if we are concerned about the impact of gradual climate change, then we should focus on policies that can reduce the harms people face today that might be made worse in the future. Creating an environment in which economic development can take place seems in general the best form of insurance, since it will enable people who are currently at the whim of the weather to diversify their economic activities and thereby become more robust in the face of all manner of future challenges.
As Southgate and Songhen point out, reducing government control over land and water resources would enable people better to identify ways of managing those resources in sustainable ways. Removing subsidies and other interventions that incentivise the use of flood plains and other land likely to be at greater risk as a result if climate changes adversely also seems sensible. Meanwhile, specific policies aimed at reducing exposure to various pathogens and other causes of ill-health may be desirable – but for the most part these would take the form of removing perverse interventions and providing an enabling environment for positive interventions to occur.
Adaptation may well be the most cost-effective option for addressing gradual, mostly benign AGW. But what happens if the warming is neither gradual nor benign? Various extreme scenarios have been envisaged, from a climate flip (a sudden switch into an ice age resulting from feedback effects following a substantial rise in temperature), to runaway warming (resulting from the release of methane stores beneath frozen peat bogs, the drying and consequent burning of subtropical rainforests, and other factors). How should humanity address such threats?
In the case of potentially catastrophic but highly uncertain climate change (no probability can be assigned because of the chaotic nature of the climate), it seems reasonable to divert a small proportion of investable resources into measures that could reduce the likelihood of such a catastrophe materialising. But how much and into what measures?
Most policy analysts focus primarily on one “solution”: reducing greenhouse gas emissions. But it is not clear that this is the optimal solution. Let’s think it through. If rich countries reduce emissions by, say, 5 per cent below 1990 levels – i.e. the Kyoto Protocol commitment but continued indefinitely – this might cost us somewhere between $50 billion and $500 billion a year. Yet, the impact would be to delay warming by only a few years. Meanwhile, it seems plausible that at some point in the coming century, a dreaded ‘tipping point’ might still be passed beyond which catastrophe becomes inevitable; the investment in reducing emissions might delay the onset of the catastrophe by a few years but on its own that would seem to have little real merit. In other words, we might end up blowing a trillion dollars and still find ourselves without a planet.
Meanwhile, if governments took more drastic action to hinder emissions -- for example globally cutting emissions to 20 per cent below 1990 levels by 2020 and keeping them there -- the probability of climate catastrophe might be reduced, but only by massively increasingly the likelihood of global economic catastrophe. Indeed, it seems plausible that beyond an economic catastrophe, a global war might result, with those countries seeking to impose carbon constraints fighting with other countries whose populaces refuse to accept such limitations being imposed upon them.
In that light, carbon control per se doesn’t seem like a very smart solution. Which is why some analysts have been looking for more acceptable alternatives. Specifically, geoengineering is now being taken seriously as an alternative way to address climate catastrophe, should the threat become concrete (Cicerone, 2006; Crutzen, 2006; Barrett, 2008). For example, Nathan Myhrvold and colleagues at Intellectual Ventures calculate that the climate could be kept from warming dangerously for as little as $10 million a year by injecting sulphur dioxide into the upper atmosphere (Levitt and Dubner, 2009) – a drop in the stratosphere compared to the Kyoto Protocol and similar proposals to cut carbon emissions.
These proposals are still speculative but they give a sense of what might be possible. While much work needs to be done to understand better how they would work and what consequences (both beneficial and adverse) they might have, Wigley (2006, p. 452) points out that the natural experiment represented by the eruption of Mount Pinatubo, which reduced global mean temperatures by around 0.5C for over a year, did not “seriously disrupt the climate system,” so emitting similar amounts of sulphur artificially should present “minimal climate risks.” Certainly, geoengineering seems to offer a plausible solution to the possibility of climate catastrophe in a way that attempting to reduce carbon emissions simply doesn’t.
Note, however, that it is not necessary to begin firing sulphur into the stratosphere just yet, since there is little reason to think that we are close to a tipping point. What does make sense today is to invest in improving our knowledge of the climate system and in developing potential geoengineering systems. And, of course, we should encourage politicians around the world to remove barriers to adaptation as soon as possible.