Introduction to Climate Change. Rodel D. Lasco Professor University of the Philippines

Transcription

1 RD Lasco 1

2 Introduction to Climate Change Rodel D. Lasco Professor University of the Philippines

3 Outline The climate system What is climate change? Evidence for climate change Predicted change in climate Impacts of climate change RD Lasco 3

4 Introduction Climate change the most serious environmental threat facing mankind effects threaten the capacity of the earth to sustain life RD Lasco 4

5 1. The Climate System An interactive system consisting of five major components: atmosphere Hydrosphere Cryosphere land surface biosphere forced or influenced by various external forcing mechanisms RD Lasco 5

6 Schematic view of the components of the global climate system Source: IPCC, 2001 RD Lasco 6

7 weather: hourly or daily fluctuations in the atmosphere climate: the average of a series of weather events typically, weather statistics averaged over 30- year period the primary source of energy that drives climate is radiation from sun to maintain long term thermal equilibrium, the earth must re-radiate back to space same amount absorbed RD Lasco 7

8 The Earth s annual and global mean energy balance. Source: Kiehl and Trenberth, 1997 RD Lasco 8

9 The Earth s annual and global mean energy balance Of the incoming solar radiation, 49% is absorbed by the surface. That heat is returned to the atmosphere as sensible heat, as evapotranspiration (latent heat) and as thermal infrared radiation. Most of this radiation is absorbed by the atmosphere trace gases, such as carbon dioxide (CO 2 ), methane (CH 4 ), nitrous, oxide (N 2 O) and ozone (O 3 ) absorb and emit infrared radiation This causes a greenhouse effect. RD Lasco 9

10 2. What is Climate Change? UNFCCC: Climate change: a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods IPCC: any change in climate over time, whether due to natural variability or as a result of human activity. RD Lasco 10

11 The Enhanced Greenhouse Effect GHGs act like a blanket that makes earth warmer earth s climate has been stable for about 10,000 years (mean T not > 1oC per century) RD Lasco 11

12 radiative forcing: any change in the average net radiative balance at the top of the atmosphere Due to natural or man-made causes increase in GHGs will result in positive radiative forcing causes enhanced greenhouse effect which tends to warm the lower atmosphere and surface RD Lasco 12

13 any radiative forcing will alter atmospheric and oceanic temperatures, weather patterns, and the entire hydrologic cycle climate variations may occur naturally (e.g. ENSO, aerosol from Pinatubo) necessary to distinguish anthopogenic changes RD Lasco 13

14 GHGs have different global warming potential (100 years): CO 2 = 1 CH 4 = 23 N 2 O= 296 RD Lasco 14

15 IPCC 2001 RD Lasco 15

16 temperature ( o C) Carbon dioxide and temperature last 420, 000 years CO 2 (ppm) , , ,000 years before present 100,000 0 Source: Jones, 2002 RD Lasco 16

17 GDP Per Capita ($000/person) Global Energy Wealth Relationship (Killeen, 2003) Poverty Burkina Faso El Salvador Bangladesh United Kingdom Mexico Japan France China Affluence Poland South Korea Russia Energy Consumption Per Capita ('000 BTU/person) United States. Source: Energy Information Administration, International RD Lasco Energy Annual 2000 Tables E1, B1, B2; 17 Gross Domestic Product per capita is for 2000 in 1995 dollars. Updated May 2002

18 3. Evidence of Climate Change IPCC 2001 conclusions: 1. an increasing body of observations gives a collective picture of a warming world and other changes in the climate system 2. Emissions of GHGs and aerosols continue to alter the atmosphere 3. there is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities RD Lasco 18

19 The global average surface T has increased over the 20 th century by about 0.6 o C Snow cover and ice extent have decreased. Global average sea level has risen and ocean heat content has increased m during the 20 th century RD Lasco 19

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22 Figure A-1: Precipitation Annual RD Lasco 22

23 Figure A-2: Temperature Annual RD Lasco 23

24 Figure 11-1: Location and countries covered in the Tropical Asia region RD Lasco 24

25 Figure A-13: Observed annual temperature changes for the Tropical Asia region. RD Lasco 25

26 4. Predicted Climate Change IPCC 2001 projections for 2100: 1. The globally averaged surface T will increase by 1.4 to 5.8oC 2. Global average water vapor concentration and precipitation will increase 3. Global mean sea level will rise by 0.09 to 0.88m RD Lasco 26

27 Simulated Global Warming (Source: Jones, 2002) RD Lasco 27

28 Temperature Change (IPCC, 2001) RD Lasco 28

29 SRES sea level rise to 2100 (IPCC, 2001) RD Lasco 29

30 Figure 20: The annual mean change of the temperature (colour shading) and its range (isolines) (Unit: C) for the SRES scenario A2 (upper panel) and the SRES scenario B2 (lower panel). Both SRES scenarios show the period 2071 to 2100 relative to the period 1961 to 1990 and were performed by OAGCMs. (IPCC, 2001) RD Lasco 30

31 Impacts of Climate Change RD Lasco 31

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33 Figure TS-3: Pattern of changes in runoff (a) HadCM2 ensemble mean (b) HadCM3 RD Lasco 33

34 Figure TS-4: Ranges of percentage changes in crop yields (expressed in vertical extent of vertical bars only) spanning selected climate change scenarios with and without agronomic adaptation (IPCC, 2001) RD Lasco 34

35 Change in Climatic Elements and Vulnerable Region Primary Change Primary Impacts Secondary Impacts Sea-Level Rise C (10- to 45-cm sea-level rise) Bangladesh Sundarbans Inundation of about 15% (~750 km2) Increase in salinity Loss of plant species Loss of wildlife Economic loss Exacerbated insecurity and loss of employment ~2 C(-5 to 10% rainfall; 45-cm sea-level rise) Bangladesh lowlands About 23-29% increase in extent of inundation Change in flood depth category Change in monsoon cropping pattern Risk to life and property Increased health problems Reduction in rice yield Source: IPCC, 2001 RD Lasco 35

36 Country Sea Level Rise (cm) Potential Land loss km2 % Population Exposed Million % Bangladesh Bangladesh , India 100 5, Indonesia 60 34, Japan 50 1, Malaysia 100 7, >0.05 >0.3 Pakistan 20 1, n.a. n.a. Vietnam , RD Lasco 36

37 Thank You! RD Lasco 37