Coping with Global Warming and Climate Change

The Intergovernmental Panel on Climate Change (IPCC 2007, p. 9) has identified five key areas subject to impacts from increasing global average temperature: water, ecosystems, food, coasts, and health. A closer reading of the text of the IPCC report shows that many of the most serious impacts on the nonwater areas are, in fact, mediated via water. So, for instance, impacts on food are largely due to hydrological changes; in fact, aridity has major impacts on food, ecosystems, and human health. The pivotal role of water impacts, and hence water’s importance to adaptation, is also stressed in the Stern Report (2006). Thinking about the relative issues involved in climate change, Mike Muller (2007) of the Global Water Partnership (GWP) said, “if it’s mitigation, then the focus is rightfully energy, and if it’s adaptation, it will be water resources!” By this he implied that the bulk of the mitigation strategies for climate change deal with handling the use of energy resources, while the adaptation strategies will be mostly driven by water concerns. Hence, we should focus on the water-adaptation strategies, bearing in mind that adaptation for other sectors may include many of the same, or similar, strategies.

There is a huge and rapidly growing literature on climate change that is beyond the capacity of any one individual to comprehend. Nevertheless, at least three broad hypotheses about climate change and global warming emerge from the literature:

It seems to me, however, that whichever of these hypotheses one endorses, there is still a question as to what to do in meeting future water demands. If we are interested in adaptation to global warming and climate change, it is irrelevant which of the second and third hypotheses you accept because operationally there will be no differences among the adaptation strategies that one should follow, but major differences if following a mitigation strategy. Surprisingly, even accepting the first hypothesis leaves one in a strikingly similar situation—how to plan for the future under highly uncertain outcomes. This is identical to the problems faced under the other two hypotheses, the only difference being the use of a stationary-state stochastic model of the future rather than a nonsteady-state model. The issue in all cases boils down to how we deal with uncertainty in making decisions about water planning and management; water engineers and hydrologists are supposedly expert at making such forecasts in a very uncertain world.

Rising global incomes and a concomitant increase in per capita consumption will lead inexorably to serious consequences for the water resources in many areas of the globe, regardless of climate change. This is the old Malthusian population versus resources debate from the early 1960s, only now we have India and China moving into the middle classes in a big way. Keyfitz (1976) pointed out 30 years ago—that the growing middle class and its consumption patterns are going to be the major problem for environmental sustainability. How we adapt to meet these demands will be the major struggle for the remainder of this century.

In planning for the future we must also be aware of unintended consequences of our actions. One example of this is the current U.S. attempt to mitigate climate change by reducing consumption of carbon-based fossil liquid fuels. We are rushing headlong toward biomass-based liquid fuels. Because of their huge demand for cropland, water, and agricultural chemicals, the widespread development of biomass fuels could be a disaster for the poor people of the world whose food budgets cannot compete with the middle class love affair with its automobiles.

The need to make a distinction between mitigation and adaptation arises because, if we were concerned with mitigation of the consequences of our actions, it would make a huge difference which of the three hypotheses one believed. If anthropogenic causality is assumed, we have a panoply of social and technical fixes (switch from carbon-based fuels, life-style changes, etc.) that could be applied differently under the different assumptions of the scenarios. If natural causes are assumed, our mitigation methods are greatly reduced, maybe restricted to only one—“living with global warming”—and making plans accordingly.

The nice thing about adaptation is that it is “blind”—once one chooses the scenarios for the future, one does not have to decide whether one believes in any one of the hypotheses: all of them have to be dealt with using essentially identical approaches. The problem now focuses upon the portfolio of policies and technologies to be selected. If you tell me a scenario for the future, I will be able to choose an optimal adaptation strategy that will maximize the expected benefits or minimize the regrets associated with choosing the wrong portfolio, regardless of my beliefs about the causality of the change.

Looking at recent climate events from an historical point of view reveals the Little Ice Age (1300–1800 A.D.), the medieval warming (900–1100 A.D.), the Roman warm period (200–600 A.D.), and even further back, the demise of the Mesopotamian civilizations of the Fertile Crescent. What these data show (from historical records, tree rings, mud varves, coral reefs, stalagmites, etc.) is a wide range of temperature and aridity variation over the past several thousand years, with a possible cycle on a millennial time scale. We see in the historical record that higher temperatures and even longer droughts have occurred than were predicted for the remainder of this century by the recent IPCC models.

I find this convincing evidence for a secular shift in the climate to warmer, and drier/wetter, depending upon location, at least over the remainder of this century. This will require serious thinking and possibly action over the next 20–50 years. Based upon recent political and social discussions, I am also convinced that little can be done to stabilize the ${\mathrm{CO}}_2$ levels at any reasonable levels, and that we need to think seriously about how to adapt to the almost-certain global warming. Of course, for many other environmental, social, and economic reasons, we must reduce our consumption of fossil fuels, but regardless of what one thinks about the role of ${\mathrm{CO}}_2$ , we are left with adaptation to global warming as a major, sensible strategy.

Two kinds of adaptation have been characterized by the IPCC: autonomous adaptations, which arise over time in response to altered demands, and planned adaptations, which are planned in advance of the climate change. Of these two types, autonomous adaptation is probably the most likely to be successful over long periods of climate change. Demand reduction in response to price increases and coastal protection and zoning in response to ever-increasing damages or increasing insurance premiums are examples of this type of adaptation. The best part of autonomous adaptation is that little or no government intervention is required. Socioeconomic processes adapt over time to newly objective conditions of hydrological changes, but if the changes are abrupt, then the response time may be too slow for sufficient autonomous adaptation to occur. Under these circumstances, we would need to have some planned adaptation measures on hand, ready to be implemented.

On the other hand, planned adaptation, which typically relies on government action, usually focuses on infrastructure investments or on proactive land use and other controls set up in anticipation of the consequences of climate change. These measures should help to hedge against errors in the estimation of future demand for and supply of water services by planning for increments into the future for staged construction of storage reservoirs, pipelines, treatment plants, etc. For instance, one could plan to instigate floodplain and coastal zoning for current 100-year floods but also update zoning every 5 years in response to new data on flood frequency. One could also help the process of autonomous adaptation along by instigating forward-looking demand-and-supply management plans for municipal and industrial water use.

We should be vigilant against the hijacking of climate change by the celebrity doomsayers with predictions of New York City being under $20\mathrm{ft}$ of water, multiple killer hurricanes, and 300 million climate refugees. It will be hard to keep the conversation focused on what we know and the scientific underpinnings of our knowledge as we explore the real effects of climate change. This will tilt the policy frame from adaptation to mitigation. In addition, maintaining an adaptation stance is made much harder by past events and natural catastrophes such as the 2005 Asian tsunami and Hurricane Katrina and the widespread Asian floods of 2007. These events are still not understood by society at large but should point us toward prudent a priori adaptation measures. It is hard to see how we could mitigate the occurrence of these types of events.

From a scientific point of view it is imperative for water scientists and engineers to work closely with climatologists to learn from such events and improve the quality of their short- and long-term climate predictions. In the long run, the scientific/technical/social dimensions of water engineering have to become a bridge between climate change and the creation of a sustainable society.