Unformatted text preview: Week 14, lecture 1 The case for action on climate change
GEOLl50: Climate Change University of Southern California, Los Angeles 1 Let us recap this semester
The Earthʼs surface is warming We understand why: itʼs us We did it by burning fossil fuel If we continue it will only get worse Projected climate change will likely have huge impacts on the biosphere (that includes us) We have 3 choices 2 The Group I Contribution to the IPCC be Assessed by WGI in AR5 Working Physical Science Basis: Latest Findings toFifth Assessment Report The Earth is Warming
IPCC (2007): Warming in the climate system is unequivocal...
also detectable in: Tropospheric temperatures, Arctic sea ice, Global SSTs, Glacier retreat, Water Vapour, Frequency of warm nights, Rainfall intensity, Precipitation over the extratropics , Hurricane intensity, Areas aﬀected by Drought, Heat waves (IPCC, 2007, Fig. SPM-3)
3 Arctic Sea-ice Extent
http://nsidc.org/arcticseaicenews/ Figure 12. Arctic sea ice extent over the ﬁve days leading up to and including September 16, 2007 compared to the average sea-ice minimum extent for the period 1979- 2006. Sourced from the NASA/Goddard Space Flight Center Scient Visualization Studio. THE COPENHAGEN DIAGNOSIS > 31 4 s Contribute to Climate Change T with Natural Influences? are he Earth is warming because of rising concentrations of greenhouse gases causing se gasknown releases d aerond outenergy rties of g of the 1750), warmgreatly such as Industrial Revolution greens oxide PhysicsFigure 1. Atmospheric concentrations of important long-lived green-2 is FAQ 2.1, and paleoclimate teaches us that CO a house gases over the last 2,000 years. Increases since about 1750 are attributed to very strong determinant of global temperature
human activities in the industrial era. Concentration units are parts per million (ppm)
5 The Modern Carbon Cycle Human Emissions (7Gt/yr) e rise since ~1750 is no doubt due to fossil fuel burning 6 Greenhouse Gases: the invisible blanket 7 The Physics of Climate Change
is embedded in climate models Forcings Climate Response
Consistent with observed changes?
8 Chapter 9 Attribution of Climate Change Understanding and Attributing Climate Cha All forcings Each line represents a model simulation
Natural Forcings only None of the 20+ IPCC climate models can reproduce the late 20th century warming without putting in anthropogenic forcing
the atmosphere (the troposphere) and cooling higher up in the stratosphere. This is another ‘fingerprint’ of change that reveals the effect of human influence on the climate. If, for example, an increase in solar output had been responsible for the recent climate warming, both the troposphere and the stratosphere would have warmed. In addition, differences in the timing of FAQ 9.2, Figure 1. Temperature changes relative to the corresponding average for 1901-1950 (°C) from decade to decade from 1906 to 2005 over the Earth’s continent as well as the entire globe, global land area and the global ocean (lower graphs). The black line indicates observed temperature change, while the coloured bands show the combined range covered by 90% of recent model simulations. Red indicates simulations that include natural and human factors, while blue indicates simulations that includ only natural factors. Dashed black lines indicate decades and continental regions for which there are substantially fewer observations. Detailed descriptions of this ﬁgure an the methodology used in its production are given in the Supplementary Material, Appendix 9.C. the 20th-century warming cannot be explained by only n ural internal variability and natural external forcing fact Confidence in these estimates is increased because prior to 9 industrial era, much of the variation they show in North Hemisphere average temperatures can be explained by episo 9 cooling caused by large volcanic eruptions and by changes The Group I Contribution to the IPCC be Assessed by WGI in AR5 Working Physical Science Basis: Latest Findings toFifth Assessment Report IPCC (2007): Continued GHG emissions ... would induce many changes ... that would very likely be larger than those observed ...
(IPCC, 2007, Fig. WGI-SPM-6) Change in Temperature (!C), Scenario A2 Also, look forward to : sea-level rise, melting glaciers, disappearing Arctic sea-ice, increased frequency of droughts, ﬂoods, heat waves, more intense hurricanes, etc.
10 Water: rich get richer, poor get poorer
Most climate models (like this one) predict an intensiﬁcation of the Hadley cell as a response to greenhouse warming. is is projected to signiﬁcantly stress Southwestern hydrology in the coming decades...
http://www.ldeo.columbia.edu/res/div/ocp/drought/mechanisms.shtml 11 From global warming to global change
Hydrological Climate Change, Food Insecurity and Hunger
Key Messages for UNFCCC Negotiators
THE DOUBLE-HEADED RISK
The consequences of consequences of climate change include a high risk of armed conflict in 46 countries with a total population of 2.7 billion people, and a high risk of political instability in a further 56 countries with a total population of 1.2 billion. Ecological
NORWAY FINLAND SWEDEN
ESTONIA LATVIA LITHUANIA DENMARK
NORWAY IRELAND U. K. NETH. FINLAND SWEDEN GERMANY
ESTONIA RUSSIA POLAND BELARUS CANADA
IRELAND U. K. BEL. DENMARK LUX. CZECH LATVIA REP. UKRAINE LITHUANIA SLOVAKIA MOLD. AUSTRIA NETH. HUNGARY FRANCE SWITZ. POLAND BELARUS GERMANY SLOVENIA ROMANIA CROATIA
BEL. LUX. FRANCE SWITZ.
PORTUGAL AUSTRIA CZECH REP. SERBIA UKRAINE SLOVAKIA B-H
SLOVENIA CROATIA SPAIN
SPAIN HUNGARY ITALY ROMANIA MOLD. MONT. BULGARIA KAZAKHSTAN MAC. Map key:
I A: States facing a high risk of armed conflict as a knock-on consequence of climate change I B: States facing a high risk of political instability as a knock-on consequence of climate change I C: Other states
BERMUDA ITALY B-H SERBIA MONT. BULGARIA MAC. ALBANIA ALBANIA GREECE UZBEKISTAN
GEORGIA ARM. AZERB. MONGOLIA KYRGYZSTAN NORTH KOREA ALGERIA MOROCCO
MOROCCO ALGERIA BAHAMAS DOM. REP. HAITI TUNISIA TUNISIA
MALTA MALTA GREECE
CYPRUS LEBANON ISRAEL TURKEY CYPRUS TURKMENISTAN TAJIKISTAN LEBAN
KUWAIT CHINA SOUTH KOREA JAPAN AFGHANISTAN IRAN PAKISTAN
QATAR JORDAN SAUDI ARABIA LIBYA WESTERN SAHARA
PUERTO RICO ANTIGUA & BARBUDA BAHRAIN NEPAL MEXICO
CUBA BELIZE JAMAICA GUATEMALA EL SALVADOR HONDURAS NICARAGUA PANAMA EGYPT BHUTAN INDIA BANGLADESH U.A.E. TAIWAN MAURITANIA CAPE VERDE
BARBADOS MALI NIGER BURKINA FASO
GHANA TOGO BENIN OMAN CHAD SUDAN NIGERIA CENTRAL AFRICAN REP. CAMEROON CONGO GABON DEM REPUBLIC OF CONGO UGANDA RWANDA BURUNDI ETHIOPIA ERITREA YEMEN DJIBOUTI SOMALIA INDIA BURMA LAOS ST KITTS & NEVIS DOMINICA ST LUCIA ST VINCENT & THE GRENADINES GRENADA SENEGAL THE GAMBIA THAILAND CAMBODIA VIETNAM PHILIPPINES Technical note The IPCC’s Fourth Assessment Report of 2007 shows that global warming will have global effects, varying in both kind and degree. Research for this report identified 102 countries* as being at risk of significant negative knock-on sociopolitical effects, using three criteria for selection: 1. Their presence on a variety of international watch lists: the UK Department for International Development’s ‘proxy list’ of Fragile States, the Global Peace Index ranking of 121 states (bottom 50 positions), the International Crisis Group ‘crisiswatch’ list, the World Bank’s list of Low Income Countries Under Stress; 2. The presence of an operational UN peacekeeping force; 3. The prospect of, or their engagement in, economic or political transition (e.g., from autocracy towards democracy or leadership succession). Within this group of 102, 46 countries were identified as facing a high risk of armed conflict. Primarily these are countries with current or recent experience of armed conflict, because this is a reliable indicator of propensity to further violence. In addition, particularly weak institutions of government and very poor economic performance were used as guides to the selection. The larger map does not make predictions but indicates risk. It should be borne in mind that armed conflicts vary widely in their levels of lethality and in whether they occur at a local, national or regional level. The smaller map shows countries’ exposure to climate change, based on the A1 scenario (approximately “business as usual”) used by the IPCC. COSTA RICA TRINIDAD & TOBAGO VENEZUELA GUYANA SURINAME FRENCH GUIANA GUINEA-BISSAU GUINEA SIERRA LEONE LIBERIA SRI LANKA MALDIVES MALAYSIA BRUNEI PALAU COLOMBIA ECUADOR COTE D'IVOIRE EQUATORIAL GUINEA SAO TOME & PRINCIPE KENYA SINGAPORE MALAYSIA INDONESIA
PAPUA NEW GUINEA TIMOR-LESTE COMOROS SAMOA MADAGASCAR MAURITIUS TONGA FIJI SOLOMON ISLANDS KIRIBATI BRAZIL
ANGOLA TANZANIA PERU
ZAMBIA BOLIVIA NAMIBIA MALAWI MOZAMBIQUE ZIMBABWE BOTSWANA PARAGUAY VANUATU CHILE SWAZ. AUSTRALIA ARGENTINA
URUGUAY LES. SOUTH AFRICA Global exposure to climate change
FALKLAND ISLANDS NEW ZEALAND Humanitarian *A full listing of these countries can be found at the end of the references on page 44. MAP © INTERNATIONAL ALERT DESIGN: D.R. INK Geopolitical Map key:
I Serious-extreme I Moderate-significant 12 Wait, doesn’t Earth’s history teach us something?
It does: climate has always changed At times, Earth has been much: Colder Warmer And almost every time, CO2 was involved Can we learn a few lessons?
13 The Group I Contribution to the IPCC be Assessed by WGI in AR5 Working Physical Science Basis: Latest Findings toFifth Assessment Report 1. CO2: Higher levels and more rapid increase Lesson #1: 2009: 387 ppm CO2 and temperature go hand in hand (Siegenthaler et al., 2005; Lüthi et al., 2008, NOAA) 14 Lesson #2: e Climate system can change abruptly Are we poking an angry beast? 15 Lesson #3: Even when climate is relatively stable... 16 … persistent drought is enough to topple advanced civilizations
LONG-TERM CHANGES IN DROUGHT AREA IN THE 'WEST'
100 80 60 40 DRIER 20 0 THE CENTRAL DATES OF THE SIGNIFICANT (p<0.05) EPOCHS ARE INDICATED WITH ARROWS Lesson #3: % DROUGHT AREA 1150 1253 936 1034 WETTER 1321 1613 1829 1915 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 YEAR Anasazi Akkadians
17 " Man learns om History that Man doesn’t learn om History. ~Hegel All right, but from Science?
18 Civilization as a geosystem Today, life still changes the game Human civilization has reached the status of geologic force Our species now has the planet’s destiny in its hands
19 Climate affects everything, and everything affects climate 20 So what to do about it?
1. Do nothing
curl into fetal position and wait for crash. (Silly) 2. Adaptation
“initiatives and measures to reduce the vulnerability of natural and human systems against actual or expected climate change effects” Pros: we’ve always done it. Cons: glaciers, coral reefs, polar bears and poor people can’t adapt 3. Mitigation
“measures or actions to decrease the intensity of radiative forcing in order to reduce the magnitude of climate change” Pros: Only sensible solution in the long run. Cons: more costly and will take a long time to implement and bear fruit 21 The economics of climate change In his 2006 report Lord Stern suggested that it would cost the world between 1-2% of GDP to avoid the worst effects of climate change. Failure to do so could risk global GDP growth being up to 20% lower than it otherwise might be. “Tackling climate changeis much e cost of inaction is the pro-growth strategy for the longer term and it costbe done in a way that does not cap greater than the can of action the aspirations for growth of rich or poor countries."
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