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042009 Science Of Climate Change: Overview For Community Organizations Dr Tess Perez


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Science Of Climate Change: Overview For Community Organizations
Dr Tess Perez National Grassroots Conference on Climate Change
Balai Kalinaw, UP Diliman
20-21 April 2009

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042009 Science Of Climate Change: Overview For Community Organizations Dr Tess Perez

  1. 1. Climate Change and the Philippines • Reviewing the Science • Detecting the Changes • Impacts on the Philippines • Responses Department of Environmental Science Ateneo de Manila University Head, Regional Climate Systems Manila Observatory
  2. 2. Atmospheric pressure (millibars) 0 200 400 600 800 1,000 120 75 Temperature 110 Pressure 65 100 Thermosphere 90 55 Mesopause 80 Heating via ozone Altitude (kilometers) 45 Altitude (miles) 70 Mesosphere 60 Stratopause 35 50 Stratosphere 40 25 30 Tropopause We are fish 20 Ozone “layer” 15 swimming 10 Troposphere 5 under a sea 0 of air! –80 –40 0 40 80 120 (Sea Pressure = 1,000 Level) Temperature (˚C) millibars at ground level
  3. 3. Types of Air Pollutants Primary CO CO2 Pollutants SO2 NO NO2 SO3 Most hydrocarbons HNO3 H2SO4 Most suspended particles H2O2 O3 PANs – Most NO3– and SO4 2 salts Secondary Pollutants
  4. 4. Energy in = Energy out Solar radiation Reflected by atmosphere (34%) Radiated by UV radiation atmosphere as heat (66%) Lower Stratosphere (ozone layer) Visible Absorbed light Greenhouse Troposphere by ozone effect Heat Heat radiated Absorbed by the earth by the earth Earth
  5. 5. Greenhouse Effect (a) Rays of sunlight pwarm the (b) Earth's surface absorbs muchcoming (c) As concentrations of greenhouse earth's surface. degrades it to longer-wavelength gases rise, more heat to the lower infrared radiation (heat), which rises atmosphere. iabsorbed by molecules of greenhouse gases awarms the lower atmosphere.
  6. 6. Reviewing • Greenhouse warming makes earth habitable the – Without CO2, Earth’s mean Science temperature will be about -18°C (no liquid water) • Unprecedented rise in CO2 concentrations is causing global warming, environmental damage
  7. 7. Inconvenient Truths • It’s our fault – Impact of human CO2 emissions now exceed natural influences • It will warm up – Forecasting tools work, and they predict a warmer planet
  8. 8. What about the Philippines? • Many well-known impacts of global warming (GW) not applicable to RP – Deadly heat waves are unlikely, no melting glaciers around – Tropical, marine conditions tend to keep weather and climate stable – GW must be distinguished from local warming (Urban Heat Island Effect)
  9. 9. Is it just the Urban Heat Island Effect ? • UHI – Warming of urban areas due to removal of trees and water bodies, and replacement with concrete and metal • Many weather stations record a steady warming due to UHI, not GW  Stations far away from cities still record a steady warming, though not as large as those in urban areas  Other indicators are also consistent with GW
  10. 10. Climate Change and the Philippines • Likely Effects of Global Warming on the Philippines: – Sea level rise – (a) Temperature, (b) rainfall and (c) tropical cyclone activity . . . – . . . Which then cause impacts on other sectors: agriculture, forests, water resources
  11. 11. Sea Level Rise in the Philippines Perez et al. 1999 Manila Bay (Blue) Legaspi (Red) Hulme and Sheard 1999 Yanagi and Akaki 1994
  12. 12. Mactan Island, Cebu
  13. 13. Northeast MManila
  14. 14. Bulacan-Pampanga
  15. 15. Trends in Regional Surface Temperatur es Trends in number of hot days and warm nights (inset). Large symbols indicate where p 0.05. From • Manton et al. Nearly all non-urban 2000. stations in the region show a rise in mean temperatures between 1960 to 1998 – More hot days, warm nights, fewer cold days and nights • Not enough to cause heat waves, but may affect agriculture –
  16. 16. Tropical Cyclones (TCs) and Global Warming: Quick Facts • Typhoons form in warm waters (>27°C) – Fewer typhoons in January to March, most frequent in July to November – Typhoons affect Mindanao mainly in December when sea surface temperatures (SSTs) remain warm enough • In theory, warmer SST means more
  17. 17. Geographic Trends in Tropical Cyclones 1 Annual increase in number of TCs. Shading indicates 0 .8 where p 0.01. 40N 0 .6 (From Anglo 2005). 0 .4 0 .2 0 20N -0 .2 -0 .4 -0 .6 -0 .8 0N 100E 120E 140E 160E -1 • Number of tropical cyclones appearing in the Western Pacific has been increasing • In the Philippines, the rise in typhoon crossings is most pronounced over Visayas
  18. 18. Stronger Typhoons? • Effect of GW on TC strength is currently the subject of intense scientific debate – Other TC requirements: uniform winds along vertical, enough moisture throughout troposphere – Not clear how global warming will change these • Skeptics: Observed rise in TC strength due to (i) better observations, or (ii) natural variation • What is certain: Philippine populations are much more vulnerable to typhoons than before
  19. 19. Changes in Regional Rainfall Extremes, 1961 to 1998 (Manton et al 2001) Change in the frequency of days Change in the proportion of total with rain annual rainfall contributed by heavy rain • What this can mean: longer dry periods, but heavier rains during wet season
  20. 20. Changes in Mean Annual Rainfall over the Philippines NORMAL EL NINO LA NINA ALL YEARS 20 20 20 20 15 15 15 15 10 10 10 10 5 5 5 5 120 125 120 125 120 125 120 125 Difference in mean annual rainfall, 1976-2000 R a in f a ll A n o m a ly ( m m ) minus 1951-1975. ENSO events based on Multivariate ENSO Index (Wolter and Timlin 1998) -8 0 0 -6 0 0 -4 0 0 -2 0 0 0 2 00 400 S ig n if ic a n c e ( p - v a lu e ) •Significant reduction over NE Luzon 0 .0 1 0 .0 5 •Significant increase over Western Visayas during La Niña •Under investigation: Change in the start of rainy season
  21. 21. Downstream Effects of a Changing Philippine Climate Making a Bad Situation Worse • Energy: Bulk of local power supply in RP comes from hydroelectricity –Any decrease in rainfall means more reliance on imported coal and oil • Agriculture –Less rain or too much rain means less harvest –Changes in timing of rain also critical –CO2 rise favors crops, but weeds like it more –CO rise can enhance corn growth, but only
  22. 22. Downstream Effects of a Changing Philippine Climate Making a Bad Situation Worse • Forests and biodiversity –Moist forests will shrink, turn into dry forests –GW may raise flood risk, worsening habitat degradation and species loss –However, human impact still much more damaging • Health –Disease vectors (i.e. mosquitoes) will expand range –Displacement due to disasters will be a worsening health issue
  23. 23. Downstream Effects of a Changing Philippine Climate Making a Bad Situation Worse • Water Resources –Rainfall is decreasing over Luzon and parts of Mindanao where major dams are found –Rainfall is increasing in the Visayas where there are no major dams –Sea level rise may cause salinity intrusion; Laguna Lake at risk • Marine Resources –Warmer temperatures can kill coral (as in 1998) –Higher CO2 in atmosphere can disrupt carbonate chemistry, make shell and bone
  24. 24. Summary of 1994 RP Emissions CO2 Waste Energy 49% Emission 7% Sector s (103 tons) Energy 50.0 Agricultur e 33.1 Industry 10.6 Agriculture Industry 33% 11% Waste 7.1 Total 100.8 1990 Total (ADB 1994): 81.9 x 103 tons
  25. 25. Where We Stand and What it Means •Even if the Philippines CO2 stops emitting Emissions CO2 there will per Capita be little effect (tons) on global warming •We should reduce emissions for its other benefits: cleaner air, less oil dependence
  26. 26. Actions Needed • Reduce exposure and vulnerability – Evacuate risky areas; enhance preparedness • Build new dams • Develop, promote new crops and farming tech • Seek co-benefits, not just mitigate – Save energy, promote clean mass transport to improve air quality – Promote renewables to reduce oil dependence • Reduce pressure on resources by
  27. 27. Plant How Many Trees? • Ateneo: 14,000 students emit 3500 tons/yr or 250 kg per student • A tropical tree removes 8 kg of CO2 per yr (or 8 tons per hectare) – Old trees don’t count; trees must reach maturity – Trees may be cut, but should NOT be burned nor allowed to rot • Number of trees each student needs to plant: ~ 31 trees per student 250 hectares to reforest 2 times the size of the campus • To sequester current emissions: each Pinoy should plant at least 100 trees per year • What this means: Planting trees enhance surroundings and habitats, but it will never be enough against climate change
  28. 28. A Better EAT LESS MEAT Response: • Heller and Keolian (2000): Impact of meat eating is nearly the same as driving a car • Philippine 1990 livestock production emitted 10,000 tons of CO2 equivalent – Equal to our industrial emissions, or 10 percent of our total • Ecology 101: feeding a vegetarian uses 90 percent less land than a meat eater
  29. 29. Final Notes • Impacts on many sectors are currently unclear, but may become more pronounced as warming continues • Science needed: Focus on understanding, adaptation and preparation • Old hard lessons: Use less energy, walk, eat more veggies; reach out to the grassroots • Filipinos should reduce their greenhouse gas emissions, but for the
  30. 30. Thank You!