Contents

Preface xi

Foreword Xttl

List of figures xv list of fit hies xk

List of ahbreviations and acronyms xxi

About the author xxiii

1 I he climate system 1

1.1 Why docs climatc vary from one placc to another? 2

1.1.1 Why mountains are colder 4

1.2 Winds and currents: the atmosphere and oceans 6

1.3.1 Ocean gvrcs and the "Roaring Forties" (or Furious Fifties) 9

1.3.2 Winds and ocean currents push against one another ... 10

Li_The ihmnoh;i1ine circulation_LO

1.5 The great heat-transporting machine 13

L5J_The •vonlinenmr* climate_L5

1.5.2 Patterns of precipitation 15

2 From climate to vegetation 21

2.1 Bionics: the broad vegetation types of the world 21

2.2 An example of a biome or broad-scale vegetation type: tropical in in tore sr_________22

2.3 The world's major vegetation types 26

2.4 Understanding the patterns 31

2.5 What favors forest vegetation 31

2.5.1 Why trees need more warmth 32

2.5.2 Why trees need more water 33

2.6 Deciduous or evergreen: the adaptive choices that plants make. . 35

2.7 Cold-climate evergreenness 40

2.8 The latitudinal bands of evergreen and deciduous forest 41

2.9 Nutrients and evergreenness 42

2.10 Other trends in forest with climate 42

? 11_Non-forest bionics 4J

2.12 Scrub bionics 43

? 14 Deserts_44

2.15 Biomes are to some extent subjective 45

2.16 Humans altering the natural vegetation, shifting bionics 45

2.17 "Predicting" where vegetation types will occur 46

2.18 Spccies distributions and climate 48

2.18.1 Patterns in species richness 51

3_Plants on the move ¿5

3.1 Vegetation can move as the climate shifts 55

3.2 The Quaternary: the last 2.4 million years 55

3.3 Biomes in the distant past 59

3.3.1 Sudden changes in climate, and how vegetation responds 63

3.4 The increasing greenhouse effect, and future vegetation change. . 67

3.5 Response of vegetation to the present warming of climate 68

3.6 Seasons as well as vegetation distribution arc changing 71

3.7 What will happen as the warming continues? 73

3.7.1 Movement of biomes under greenhouse effect warming . 76

4 Microclimates and vegetation 79

4J_What causes microclimates0 22

4.1.2 Above the surface: the boundary layer and wind speed . 80

4.1.3 Roughness and turbulence 83

4.1.4 Microclimates of a forest canopy 84

4.1.5 Under the canopy 86

4.1.6 Big plants "make" the microclimates of smaller plants. . 88

4.1.7 The importance of sun angle 90

4.1.8 Bumps and hollows in the landscape have their own microclimate-92

4.1.9 Life within rocks: endolithic lichcns and algae 94

4.1.10 Plants creating their own microclimate 94

4 111 Park colors

4.1.12 Protection against freezing 95

4.1.13 Internal heating 95

4.114_Vo la tiles from leaves

4.1.15 Utilization of microclimates in agriculture 96

±L2_From microclimates to macrocliinates %

5 The desert makes the desert: Climate feedbacks from the vegetation of arid /.ones .._..._ lill

5.1 Geography makes deserts 101

5_2_Hut deserts make* themselves_LQ2

5.2.1 The Sahcl and vegetation feedbacks 107

5.2.2 Have humans really caused the Sahelian droughts? Ill

5.3 Could the Sahara be made green? 112

5.4 A human effect on climate? The grasslands of the Great Plains in ihe USA UA

5.5 The Green Sahara of the past 118

5.6 Could other arid regions show the same amplification of change by vegetation cover? 123

5JZ_Qnsi_L24

5.7.1_Sudden climate switches and dust L21

5l&_The future_L2S

6_Forests_L31

6.1 Finding out what forests really do to climate 133

6.2 What deforestation does to climate within a region 136

6_3_Re-afforest a linn_L42

6.4 The remote effects of deforestation 143

6.5 The role of forest feedback in broad swings in climate 144

6.5.1 Deforestation and the Little Ice Age 144

6.5.2 Deforestation around the Mediterranean and drying in north Africa-\Ah

6.5.3 Forest feedbacks during the Quaternary 147

6.6 Volatile organic compounds and climate 149

6.7 Forest-climate feedbacks in the greenhouse world 151

7 Plants and the carbon cycle 153

2J_The ocean L55

7.2 Plants as a control on CO-, and 157

7.3 Methane: the other carbon gas 159

7.3.1 Carbon and the history of the earth's temperature 161

7.3.2 Plants, weathering and CO? 161

7.3.3 Plants, CO: and ice ages 165

7.4 Humans and the carbon store of plants 171

7.5 The present increase in C02 174

7.5.1 The oceans as a carbon sink 176

7.5.2 Seasonal and year-to-year wiggles in CO.? level 177

7.6 The signal in the atmosphere 181

7.7 The strength of the seasonal "wiggle" in C02 184

7.8 Accounting errors: the missing sink 184

7.9 Watching forests take up carbon 186

7.9.1 Predicting changes in global carbon balance under global warming 188

8 The direct carbon dioxide effect on plants 191

8.1 The two direct effects of CO2 on plants: photosynthesis and water balance 191

8.2 Increased CO? effects at the scale of a leaf 192

8.3 Modeling direct CO, effects 193

8.4 What models predict for increasing C02 and global vegetation. . 194

8.5 Adding climate change to the C02 fertilization effect 195

8.6 Experiments with raised C02 and whole plants 197

8.6.1 The sort of results that arc found in CO2 enrichment experiments 201

8.6.2 A decline in response with lime 202

8.7 Temperature and C02 responses interacting 202

8.8 A few examples of what is found in FACE experiments 203

8JU_Forrsis_203

8.8.2 Semi-desert and dry grassland vegetation 204

8.8.3 Will C4 plants lose out in an increased C02 world? . . . 206

8.9 Other FACE experiments 210

8.9.1 FACE studies on agricultural systems 210

8.10 Some conclusions about FACE experiments 211

8.10.1 Will a high C02 world favor C3 species over C4 species? 211

8.10.2 What factors tend to decrease plant responses to C02 fertilization? 212

8.11 There are other effects of enhanced C'02 on plants apart from growth rate 212

8.12 C02 fertilization and soils 213

8.13 C02 fertilization effects across trophic levels 215

8.13.1 Looking for signs of a CO: fertilization effect in agriculture 216

8.13.2 Looking for signs of a CO2 fertilization effect in natural plant communities 216

8.13.3 The changing seasonal amplitude of CO? 218

8.14 CO, levels and stomata out in nature 219

8.15 Direct CO? effects and the ecology of the past 219

8.15.1 Direct CO? effects on longer geological timcscales 221

8.15.2 Ancient moist climates or high CO2 effects? 222

8.16 Other direct CQ-> effects: in the oceans 224

8.17 The future direct CO2 effect: a good or a bad thing for the natural world9_224

8.18 Conclusion; the limits to what \vc can know 225

Bibliography 227

index 211

Renewable Energy Eco Friendly

Renewable Energy Eco Friendly

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable.

Get My Free Ebook


Post a comment