by Jean Jouzel
Mountain Regions
We are often asked this question: What will the consequences of warming be in France? We begin by pointing out that by around 2050 the summer we had in 2003 will be an average summer; then we mention the aspects connected to the coastal regions, some of which will be affected by the elevation of the sea level, to agriculture, to forests, to the economy, to health, and to tourism. All these aspects are discussed in a series of articles published by Greenpeace with a view toward establishing a synthesis on the impacts of climate change in France.4 But two consequences are usually pointed out. The first is connected to water resources: as is the case with the entire Mediterranean basin, they will be affected in the southern part of France. There will be less precipitation there, too, especially in the summer, and more evaporation. The second concerns our mountains. The impact of climate change will be very visible there, as illustrated by two articles published in the Greenpeace report. If warming is greater than 3°C, most of the glaciers in the Alps and the Pyrenees will be reduced to nothing. Only the largest glaciers located above 4,000 meters in the Mont-Blanc Massif will be spared but with a marked reduction of their areas and lengths. Even a 2°C warming would have notable effects on the conditions of snow cover at mid-altitude (1,500 to 2,500 meters). Thus at 1,500 meters, the number of months of snow cover would be reduced from five to four in the Northern Alps and from three to two in the Southern Alps and the Pyrenees. This would equate to a decrease of 40 to 50% in the snow cover. In high altitudes the snow cover would be reduced by about ten days, but that decrease would be more pronounced in the event of greater warming.
Beyond the consequences for winter tourism—the very existence of winter resorts and recreation areas would be threatened—the decrease in snow cover would affect other areas as well. Spring avalanches could become more frequent, and the flow of the rivers would likely change, with the peak of the spring melting occurring about one month earlier, which would affect irrigation and hydroelectric resources. We should expect a gradual rise in the upper limit of the tree line, thus limiting the zone of alpine plants. In addition, the disappearance of frozen ground associated with warming can result in sliding ground on mountainsides and falling rocks. What is true for the French mountains can be more or less applied to the entire Alpine massif and to other mountainous regions and thus affect tourism and recreational activities. For example, without snowmaking, the ski season in western North America would likely shorten substantially, with projected losses of three to six weeks (by the 2050s) and seven to fifteen weeks (2080s) in the Sierra Nevada of California (for high emissions IPCC scenarios).5 The African and some glaciers in the Andes will also be subjected to a harsh trial, in particular the smaller ones like Chacaltaya in Bolivia, which has recently disappeared. The situation is particularly alarming in South America, where many artificial lakes used for irrigation are filled almost exclusively by glacial melting.
Polar Regions: Multiple and Diverse Impacts
Given the expected differences when faced with an increase in the greenhouse effect—the Arctic’s warming is two to three times greater than the global average while that of Antarctica is much closer to the global average—it is not surprising that the impacts would be very different for the northern and southern polar regions, especially since each region varies in terms of fauna, flora, and populations.
The ecosystems are already sensitive to the changes that are occurring. For example, the abundance of krill, small shrimp that play an essential role in the food chain and are a key element in ecosystems in Antarctica, is decreasing in the southern waters, as are colonies of Weddell seals and penguins. The populations of krill and penguins vary in strict correlation with the sea ice because penguins feed mainly on krill, whose reproduction depends on the expanse of sea ice. In the Weddell Sea and in the Antarctic Peninsula, warming, which has been steadily increasing over the past fifty years, has meant a reduction in the area of the sea ice in winter and spring and thus a decrease in the number of krill and Adélie penguins by 30% in twenty years. The penguins cannot reproduce except when the sea ice surface is at a maximum, which allows us to predict their disappearance on the Antarctic Peninsula by the end of the century. Another study conducted on the Crozet archipelago indicates that a warming of only a few tenths of a degree constitutes a serious threat for the king penguin.6
Other works show that the extent of the ice also determines how marine ecosystems function in the Arctic, especially since they do not have the opportunity to adapt to the very rapid changes that are occurring. On the emerging land, some species—the Arctic fox, wild geese—have decreased greatly while others—élans, some birds—have moved to the north. Vegetation has already been modified in some regions and projections indicate that in the case of moderate warming 10% of the tundra will be replaced by forest.
A decrease in the surface area of the sea ice and its thinning will have significant consequences for certain species. Polar bears, for example, need the ice shelf as a platform to hunt seals, their main food source. The population of polar bears, which can travel thousands of kilometers per year in the regions around the Arctic, is estimated at 20,000 to 25,000, but the survival of the largest living land carnivore is in danger because of the shrinking of its habitat; polar bears, moreover, have been placed on the red list of endangered species by the International Union for the Conservation of Nature (IUCN). The first signs of decline have been observed in the Hudson Bay in Canada; a decrease of more than 30% in the next thirty-five to fifty years is anticipated, and there is a serious risk of extinction if the sea ice shrinks greatly.
Four million people, 10% of whom are native, currently live in the Arctic. There are always nomadic peoples, but more than two-thirds of this population lives in towns of more than 5,000 inhabitants. Despite its small and dispersed population, the Arctic has become an important region from both a geopolitical and economic point of view. These communities, especially the native ones, are vulnerable to climate change, but they also have a capacity for adaptation to change in their environment. However, some native peoples consider such adaptation unacceptable vis-à-vis their traditions and cultures. Thus the conference of Inuits complained to the U.S. Senate because it estimates that climate change is infringing on the rights of the community and risks leading to a loss of identity and culture.
The inhabitants of the Arctic already have and will increasingly have more problems linked to infrastructures. Some coastal regions will have to face simultaneously the melting of the permafrost, an increase in the frequency and size of storms and thus of erosion, and a rise in sea level. In the work that the Argos Collective devoted to climate refugees, Guy-Pierre Chomette and Hélène David describe their stay in Shishmaref on the northwest coast of Alaska. They relate the story of a house being discovered one morning in the sea. It had been balancing for a long time on the ocean banks and finally could not resist the erosion caused by the melting of the permafrost. Most of the 600 inhabitants of Shishmaref voted to leave their village by 2015 but without a very clear notion of their futures. The least onerous solution would involve leaving everything for the little towns located 300 kilometers farther south. A closer relocation, at some twenty kilometers inland but twice as expensive, is also foreseen.
The Political and Economic Stakes: Climate and Oil
If the current melting rate of the Arctic ice shelf continues, this will enable new links between the Atlantic and the Pacific, intensifying commercial transport and access to new fishing zones. But more important in terms of political and economic stakes, the floor underneath the ice shelf seems to contain 10 to 50% of the planet’s reserves of oil and gas. But to whom do these ocean floors belong? There are five coastal countries—the United States, Canada, Russia, Norway, and Denmark, through its sovereignty over Greenland—but the answer to the question depends on who has rights to the sea; a state bordering the Arctic Ocean can claim rights over the undersea territories located beyond 200 miles from its coast if it can demonst
rate that they form a natural prolongation of its continental shelf. That right implies a scientific expertise based in particular on a detailed cartography of the floors. The Canadians are already financing new submarines to explore the ocean floor; the Russians have used a bathyscaphe to plant a flag of the “motherland” in rustproof titanium on the ocean floor of the North Pole. Some non-coastal countries propose free access to the waters that they consider international. Fortunately the scientific projects within the framework of the 2007–2009 International Polar Year (IPY), thus in that of an international collaboration, lean toward ensuring that scientific interests supersede economic and political ones. It would then be a matter of perfecting technologies that would enable the energy treasures in the Arctic Ocean to be exploited.
As far as Antarctica is concerned, potential energy reserves are now under lock and key as a result of the Madrid Protocol signed in 1991 and in effect for fifty years unless the pressure of energy demands cause the signatories of the treaty to revisit it.
The issue of climate warming has caused scientific challenges and those that concern society to become closely connected; we can see proof of this in the high-stakes polar regions in a world needing energy resources. The polar zones seem to be peaceful spaces in an agitated world. Let’s hope that the challenges connected to climate warming and to the race for resources will safeguard those spaces of peace.
CHAPTER 15
What We Must Do
We often have the feeling that there is an absence of dialogue, an uncrossable chasm, between the scientific world and that of the political policymakers. In the case of climate warming associated with human activities, the fact that the IPCC, which is responsible for scientific assessments, was founded by two organizations that came out of the United Nations has largely facilitated the dialogue. Four years after the creation of the IPCC, in June 1992 during the first Earth Summit organized in Rio under the aegis of the United Nations, 156 countries adopted the text of the United Nations Framework Convention on Climate Change (UNFCCC), known after 1994 as the Climate Convention. Two other conventions were then held in Rio, one dedicated to the preservation of biodiversity, the other to the struggle against desertification.
The Climate Convention has been ratified by almost every country on Earth (189 governments including the European Community) and is filled with much good sense because the ultimate objective of the convention is “stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. Such a level should be achieved within a time frame sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner.”1
But that good sense, which consists of taking action because we cannot indefinitely allow the warming of our atmosphere to increase, creates a true challenge, even if the Climate Convention does not fix the level of stabilization that should not be surpassed.
Stabilizing the Greenhouse Effect: A True Challenge
We have pointed this out clearly: none of the scenarios cited in chapter 13 leads to a stabilization of the greenhouse effect. It is logical, since the mandate given to economists when they were asked to propose that set of scenarios was that they do not take into account policies put into play explicitly to fight against climate change. On the whole, none of those scenarios corresponds to what must be done, at least from the perspective of the Climate Convention. The recognized need to stabilize the greenhouse effect has given birth to a second type of scenario, that of stabilization (Table 15.1).
An initial approach, followed in the second and third reports of the IPCC, consists of defining the objective of stabilization in terms of CO2 concentration because, as we have emphasized, it is unrealistic in the long term to seek to stabilize the greenhouse effect if the concentration of CO2 is not stabilized. We must add approximately 20–30% to get a CO2 equivalent that then accounts for all the greenhouse gases. We need only examine the constraints posed by the stabilization of concentrations of CO2 alone to immediately grasp the challenge we face: this objective implies that the emissions of this gas are compensated for by sinks, regardless of the level of stabilization aimed for. If we are content with a stabilization of 1,000 ppmv of CO2, 3.6 times more than the value in 1750, which from the point of view of a climatologist is completely unacceptable, it would be necessary for annual emissions never to exceed 15 gtC (billions of tons of carbon); it would take two centuries for emissions to go below their current level (~7 gtC). If we assign ourselves a more acceptable objective, 450 ppmv, these emissions should diminish by around 2020, reach their current value before 2050, and reach less than 3 gtC at the end of the century. Between the 30 gtC of the maximum scenario, the one in which no effort is made to limit the greenhouse effect, and that of a stabilization at a concentration not too far from its current value, there must be a decrease by a factor of 10 between now and the end of the century. The gap is huge and it would be useless to hope that nature could be a big help to us because the sinks, whether continental or oceanic, will have a tendency to decrease, at least in a relative sense. We must also not forget that in the long term the absorption of emissions that will persist will probably not exceed 0.2 gtC per year, less than 3% of the current emissions connected to fossil fuel—that is to say, nothing.
Table 15.1
IPCC stabilization scenarios.
Note: The six stabilization scenarios from the IPCC are displayed in increasing order as a function of the level of stabilization of CO2 (column 1); the next columns indicate the years of peak emissions, the corresponding CO2 emissions (compared to 1990), and the temperature of stabilization compared to its preindustrial levels (IPCC, 2007).
An alternative approach, adopted in the fourth IPCC report, consists of defining a mean temperature of stabilization that should never be surpassed. It has the advantage of enabling a relationship to be established between a given stabilization scenario and the impacts of climate change associated with it. These impacts (consequences) depend above all on the warming achieved, whatever the level of warming that has been reached within the context of a scenario of stabilization or not. It is enough to refer to the preceding chapter to have an initial evaluation of the impacts linked to a given stabilization scenario. The disadvantage of this approach is that it requires a hypothesis on the sensitivity of the climate vis-à-vis an increase in the greenhouse effect. The figures given in table 15.1 are based on a sensitivity of 3°C for a doubling of the concentration of CO2, a value that coincides with the best recent estimates of a sensitivity of 2–4.5°C. Since it is important to have a few figures in mind, we have created a simplified table from the one presented in the IPCC report.
A few comments will be useful to facilitate reading the table. The six scenarios are classified in increasing order of the level of stabilization. For each scenario a certain number of simulations have been proposed; 70% of the cases studied for a given scenario have their maximum value of emission in the interval reported under “peak year,” 15% above, and 15% below. Furthermore, the CO2 emissions in 2000 were greater than those in 1990, a year of reference for the Kyoto Protocol, and the preindustrial temperature is lower by around 0.5°C than that of the period 1980–99, corresponding to what we designate, a bit arbitrarily, as the current climate. Finally, it is specified that emissions must continue to decrease after 2050. Table 15.1 illustrates the amplitude of the climatic challenge. Thus limiting warming to less than 2°C compared to the preindustrial climate may already seem beyond reach and that implies that we have to adapt to such warming, whatever we do otherwise.
This difficulty, if not impossibility, of stabilizing global warming below 2°C with respect to preindustrial climate is now clearly pointed out by specialists of energy. In its 2011 report titled “World Energy Outlook,” the International Energy Agency (IEA) concludes that “We cannot afford to delay further action to tackle clim
ate change if the long-term target of limiting the global average temperature increase to 2°C, as analyzed in the 450 Scenario, is to be achieved at reasonable cost. In the New Policies Scenario, the world is on a trajectory that results in a level of emissions consistent with a long-term average temperature increase of more than 3.5°C. Without these new policies, we are on an even more dangerous track, for a temperature increase of 6°C or more.” The report adds that “If stringent new action is not forthcoming by 2017, the energy-related infrastructure then in place will generate all the CO2 emissions allowed in the 450 Scenario up to 2035, leaving no room for additional power plants, factories and other infrastructure unless they are zero-carbon, which would be extremely costly.”
The Kyoto Protocol: A First Step
Let’s look back a bit. Once the Climate Convention was implemented in 1994, the signatories designated by the parties involved got to work. The first Conference of Parties (COP) gathered in Berlin in 1995. It recognized the privileged ties between the Climate Convention and the IPCC, which were solidified by the creation, within the convention, of the Subsidiary Body for Scientific and Technological Advice (SBSTA), whose role was to sum up for that body all the most recent information on climate changes including that provided by the IPCC.
That first COP included the Berlin mandate that aimed to reinforce the involvement of countries designated as Annex I in relation to those of the convention. This mandate stipulated, in particular, that the Annex I countries must assign themselves numeric limits and reduction objectives within precise time frames for their anthropogenic emissions and their greenhouse gas sinks. Annex I countries included relatively rich industrialized nations that had contributed historically to climate change, as well as countries in Eastern Europe and Russia that were “in transition towards a market economy” and had more flexibility in executing their obligations. All other countries, that is, developing countries and emerging countries, were in the non–Annex I group. These countries had to produce a more general report on their intentions vis-à-vis emissions and adaptations to climate changes. This mandate paved the way for the establishment of the Kyoto Protocol (COP 3) two years later.