Abstract

Interactions between climate and biodiversity are complex and present a serious challenge to scientists who aim to reconstruct the ways in which climate change has shaped life in the past and will contine to do so in the future. This chapter introduces the contributions made to climate change research by the fields of ecology and systematics and outlines how their approaches and methods have, often through necessity, become increasingly integrated. It explores: (1) how climate change has influenced evolutionary and ecological processes such as adaptation, migration, speciation and extinction; (2) how these processes determine the diversity and biogeographic distribution of species and their populations; and (3) how ecological and systematic studies can be applied to conservation and policy planning in our rapidly changing world.

Introduction to climate change, ecology and systematics

Abstract

Modelling the impacts of climate change on biodiversity in a phylogenetic context combines the disparate disciplines of phylogenetics, geographic information systems, niche ecology and climate change research. Each subject has its own approach, literature and data. The strength of an integrative research, known as ‘phyloclimatic modelling’, is that it provides novel insights into the possible interactions of life and climate over millions of years. However, the risk is that problems associated with each subject area might be compounded if analyses are not conducted with care. The continuous development of analytical approaches and the steady increase in data availability have offered new opportunities for data combination. Modelling techniques and output for climate, ecological niche modelling, phylogeny reconstruction and temporal calibration are becoming stronger, and the reliability of results is quantifiable. In contrast, there is still a desperate lack of fundamental data on organismal distribution and on fossil history of lineages. When theories of taxonomic delimitation change, there are subsequent changes in organismal names. This creates difficulty for name-based data retrieval, but techniques are being developed to reduce this problem. Improvements in theory, associated tools and data availability will broaden the applicability of phyloclimatic modelling.

Background

Modelling the impact of climate change on the world's biota is an aspirational goal dependent on the availability of both large amounts of data and substantial computing resources. These models can be used to help us understand evolutionary relationships and ecological requirements of species, and to estimate their past, present and future distributions.

Abstract

Detailed and reliable understanding of past climate change is a key ingredient in unravelling how climate has influenced life on earth and will continue to do so in the future. Palaeoclimatology and climate modelling have both made rapid strides over the past decades, and there has been fruitful two-way interaction between the two fields. The application of climate models to palaeoclimates has proved useful both in interpreting palaeoclimate proxy data and in testing the robustness and generality of climate models. Here, we give an overview of the current state of climate modelling and review recent progress in understanding deep-time climate change, with emphasis on problems where climate models have played a salient role. By suitably adjusting the concentration of atmospheric greenhouse gases, climate models can be made to replicate many key climatic transitions in the earth's history. However, important discrepancies remain between modelled climates and proxy reconstructions, particularly on the warm end of the spectrum.

Introduction

Climate science deals with reconstructing and explaining the long-term mean and variability of physical conditions in the earth's envelope. A striking feature emerging from such analysis is the vast range of timescales on which there is significant variability. Part of this variability, including the diurnal and annual cycles, is periodic and predictable, but mostly it is random and unpredictable. We know from direct experience that the weather changes from hour to hour, from day to day, and from year to year.

Abstract

This chapter discusses the abiotic (climatic, atmospheric, fire) and biotic (herbivory, competition) factors driving the origin of savanna biomes and the evolution of their dominant plant group, the grasses. C4 photosynthesis is a key innovation in grass evolution, and we outline how phylogenetic approaches have helped us understand the multiple origins of this trait and the factors driving its evolution, such as atmospheric CO2 concentrations, drought, heat and fire. C4 grasses have interacted closely with other organisms throughout their evolution, and we describe evidence for their coevolution with ungulate herbivores in savanna habitats (an evolutionary arms-race scenario). We also describe phylogenetic approaches for reconstructing ancestral niches and geographical ranges of grasses over evolutionary time. These studies reveal a close link between climate and savanna evolution, with the first C4 grasses evolving in open habitats of Africa. By reviewing the findings of several major studies, we hope to provide predictions about the fate of savannas under future global change scenarios.

Introduction

Biomes are natural communities of wide geographical extent, characterised by distinctive, climatically controlled groups of organisms (Raven et al., 2005). Savannas are among the most charismatic of such biomes because they are extremely species-rich, because their predominantly C4 grasses coevolved with a large diversity of mammalian grazers, and because their history is intimately linked with the opening up of tropical forests that occurred during the Cenozoic (in the last 65 million years), due to climate change. C4 grasses exhibit the Hatch–Slack photosynthetic pathway (Slack and Hatch, 1967).

Abstract

This chapter reviews the potential of comparative wood anatomy for climate reconstruction and for assessing the possible risks of global warming to extant woody plants. There is growing evidence that wood evolution has been driven by functional adaptations to climate change in vessel-bearing woody angiosperms, giving rise to multiple parallelisms and reversals in vessel, fibre, parenchyma and ray modifications. Despite this homoplasy, wood anatomical character complexes are phylogenetically constrained, often allowing different clades at various levels of the taxonomic hierarchy (families, genera and groups of closely related species) to be reliably identified by wood anatomical attributes alone. Examples are presented of how wood anatomical characters can be used as climate proxies, especially for mean annual temperature (MAT), and its covariables latitude and altitude. One of the great challenges of modern wood research is to model the relationships between climate and wood anatomical diversity patterns of extinct and extant plant communities in such a way that the impact of current and future climate change can be predicted reliably.

Introduction

Secondary xylem is a multifunctional, complex plant tissue that provides an ar- chive of the external signals that modified its functional attributes at different timescales, from the lifespan of a single tree to millions of years of biological evolution (Baas, 1986; Wheeler and Baas, 1991, 1993; Carlquist, 2001; Sperry, 2003; Baas et al., 2004; Poole and van den Bergen, 2006; Wheeler et al., 2007).

For twenty years the international diplomatic community has held continuous diplomatic talks on global warming but those efforts have produced very little. This chapter explains why.

My starting point is the fact that global warming is a hard problem to solve. As I showed in Chapter 2, one of the central reasons for the difficulty is that the chief pollutant, CO2, is an intrinsic by-product of the modern fossil fuel-powered economy. Deep cuts in CO2 are needed, but making those cuts will influence the economic competitiveness of nations. National policies must be interdependent. That is, what one country will be willing to adopt depends on the efforts its trading partners are making. The benefits from successful cooperation – less global warming – are abstract and arise mainly in the distant future. In the best of worlds it was never going to be easy to manage this problem.

My argument in this chapter is that when the global warming problem appeared on their radar screen the world's top diplomats opened a toolbox that had all the wrong tools for the job. They thought global warming was just another environmental problem, but the standard tools of environmental diplomacy don't work well on problems, such as global warming, that require truly interdependent cooperation. The diplomats took a hard problem and made it even harder to manage by choosing the wrong strategy. Here I will focus on the four tools that were the centerpiece of that toolbox.

Sources used

The emissions data used for the table come from the Climate Analysis Indicators Tools (CAIT) program developed by the World Resources Institute (WRI). This application combines information taken from various databases, with the emphasis on sources based on scientific studies.

The CAIT database does not provide complete information about emissions related to forests or land use change. When such information was not complete we supplemented it with the information sent by countries to the United Nations Framework Convention on Climate Change (UNFCCC) secretariat, when this was available.

The breakdown among countries by income level is the one used by the World Bank in the 2010 report on world development on the basis of per capita income thresholds from $975 to $11,905 at 2008 exchange rates.

Guide to reading the table

The first column gives the total anthropogenic greenhouse gas emissions, including forests, for the seventeen largest emitters, with the twenty-seven-member European Union being considered as a single emitter, plus France.

Energy-related carbon dioxide (CO2) emissions cover all CO2 emitted during the production and use of energy: the production of heat and electricity, the consumption of energy derived from fossil fuels in industry, buildings and transport, fugitive emissions and all other energy uses. Emissions resulting from international air and maritime transport are included. To obtain the total energy emissions considered in Chapters 3 and 4, add in fugitive methane emissions from coal mines and oil and natural gas installations.

It is very hard to make much of a dent in the problem of global climate change without inventing and deploying new, radically different technologies. Most emissions of warming gases come from industrial energy systems that will be expensive and difficult to alter until new technologies appear. In the electric power sector, for example, deep cuts in emissions are feasible with massive deployment of new renewable energy supplies or thousands of new commercial-scale nuclear reactors, among many other options. Yet today's intermittent renewable energy supply options are impractical at a large scale without new systems for storing power and assuring stability of the power grid. Expanding today's worldwide fleet of 436 nuclear reactors to perhaps 1,500 or 2,000 reactors will probably require wholly new reactor designs as well as new systems for supplying fissile fuel that are more frugal and less prone to proliferate nuclear weapons. Huge leverage on emissions probably will require rethinking the whole energy system.

This chapter is about policies that could spur invention and use of those technologies – what I will call “technology policy.” The pace of serious efforts to control warming emissions will depend, in part, on success with technology policy. I will focus on energy, which accounts for most warming gases, although big innovations may also play a role in agriculture, forestry, and other activities that also cause substantial emissions. About five-sixths of all CO2 and a large portion of other warming cases originate in the energy system.

The problem of global warming requires policy efforts in three distinct areas. One is regulating emissions that are building up in the atmosphere and causing changes in the climate. A second is boosting investment in new knowledge – so that future efforts to control emissions are better informed and so that cheaper technologies for controlling emissions are closer at hand and easier to deploy. A third is bracing for the large (possibly catastrophic) changes in climate that may occur. Each of these problems is related, but each requires its own distinct policy strategy. In this part of the book – Chapters 3 to 6 – I look at each of these three policy challenges.

This chapter and the next are about the first and most central area for policy: regulating emissions. Experts also call this “mitigation.” The best place to start building a theory to predict how individual countries will mitigate is to look at two main groups of countries. This chapter is about the “enthusiastic countries,” and Chapter 4 is about “reluctant countries.”

If a reliable world government existed then it might not be so important to look at these two groups of countries separately. The world government would set policy and then firms and people across the planet would comply. But in the real world, international policy is trickier to craft because it hinges on what every nation, individually, is willing and able to implement.

Most of my professional life has focused, in one way or another, on the ways that humans affect the global environment. Greenhouse warming is the most complex and sprawling of those global problems; politically it is the toughest to solve. It has taken a career to understand the problem, and along the way I have accumulated many intellectual debts.

Before enrolling in graduate school at MIT in the late 1980s I worked with a research group at Harvard that studied atmospheric chemistry and physics. That group, led by Mike McElroy and Steve Wofsy, taught me more about basic science of the atmosphere and oceans than I ever learned as a student. At the time, the ozone layer was the big planetary worry, and through their eyes I learned how to read and interpret the cutting-edge science. I soon shifted my academic discipline to political science, but most of my career has been an attempt at serious interdisciplinary research on atmospheric and oceanic issues. That style of research only works when the scholar can read and interpret the frontier of research across often disparate disciplines. I trace my enthusiasm for interdisciplinary research to the orbit of interesting things I learned from Mike and Steve and the many other people in Cambridge, Massachusetts working on similar atmospheric problems. They included Jim Anderson's research group (which flew a converted spy plane into the ozone hole in the late 1980s and found the smoking gun showing that humans were to blame), Dick Holland, Ron Prinn, and Mario Molina.

November 2006, Moscow. The temperature is unusually mild. Animal species, governed by the rhythm of the seasons, are unsettled. The bears in the zoo are having trouble hibernating and need to be given additional food. Several species of migratory birds, which have left on their annual journey, are turning back. Disoriented ducks are engaging in courtship displays.

April 2007, France. With temperatures 4.7°C higher than the thirty-year average, it is the warmest April ever recorded by Météo France. Crops are particularly advanced for the time of year, up to three weeks early for grains. Strawberries and cherries from south-west France are already on the market. This earliness is no one-off occurrence. Since 1945, grape harvest dates have advanced by three weeks, even a month, in certain regions. As the French historian Emmanuel Le Roy Ladurie makes clear, variations in harvest dates, recorded in parish registers since the Middle Ages, are reliable evidence for historical fluctuations in temperature.

December 2007, New South Wales, Australia. The small town of Deniliquin invested in the largest rice production programme in the southern hemisphere. In its heyday, it was able to meet the needs of 20 million people around the world. But after five consecutive years of drought, the factory has recently closed. Australian farmers have abandoned rice growing, with its heavy demand for water. The country's exports have fallen, which has contributed to food riots in Africa and the Caribbean. Of course, this is not the first time Australia has experienced drought.

It was an Englishman, Arnold Lunn, to whom we owe the development of Alpine skiing. Founder of the Alpine Ski Club in 1908, Lunn organized the first skiing competitions in Switzerland and Austria. Through his efforts, the discipline was recognized by the International Ski Federation in 1930, then by the Olympic movement. Nearly 660 skiable areas are currently used in the Alps. But this environment is particularly sensitive to warming: the Alps is one of the parts of Europe where the temperature is rising fastest. A recurrent shortage of snow is already hampering the use of some sixty ski resorts. If the thermometer rises on average by 2°C in the coming decades, a hundred or so further resorts will face a lack of snow. If it goes up by 4°C, barely 200 resorts will still be able to operate. Resorts are spontaneously turning to making artificial snow. This type of adaptation increases energy use, which raises operating costs and emits greenhouse gases. It requires water – in France more than 10 million cubic metres each winter – which is expensive to transport. But there remains one essential ingredient for the snow cannons to function: cold. When the temperature refuses to fall, the cannons cannot be used and skiers have to head up to higher altitude resorts or convert to hiking. The unfortunate Mr Lunn would no doubt be turning in his grave.

In the West, the Maldives are primarily known for the images of atoll paradise promulgated by tour operators.

In his well-known paper ‘The Tragedy of the Commons’, Garrett Hardin (1968) describes the mechanisms through which natural resources are damaged as a result of being free of cost. He focuses on the example of the communal pastureland or ‘commons’ that surrounded English villages up until the end of the eighteenth century. Under this tenure system, the villagers all had access to communal grazing land for their livestock. In a situation of demographic stagnation, this social system provided them with a measure of security. Everyone had free access to a shared resource.

With a growing population, the system tended to destroy itself. Because access to the communal grazing land was free, in making their economic calculations the herdsmen took no account of the cost of this resource to the community. It was therefore in each herdsman's interest to have his animals graze on the common as long as a positive marginal revenue remained: a few blades of grass for the last animal taken to the pasture. Inevitably the outcome was overgrazing that reduced the fertility of the common to zero and led to the destruction of the collective good.

The complexity of international climate negotiations may be appreciated if one takes Hardin's example and replaces the word ‘village’ by ‘planet’ and the word ‘common’ by ‘the atmosphere’. The growth of the planet's population and its rising living standards are a threat to a very special collective good: the stability of the climate.