Global and Sri Lanka State of Environment

University:
High School
Course:
High School Literature
Academic year:

2020
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0

Pages:

54
Author:

Thisara Hansaka

PgDEM 5104: Global and Sri Lanka State of Environment POLLUTION & CLIMATE CHANGE Dr. Jinendra Dissanayake CONTENT Pollution  Climate change  Connection between air pollution and climate change  Observed and projected impacts of climate change  Mitigation or adaption  POLLUTION  Introduction of substances or energy liable to cause harm to living beings or ecological systems, into the environment  Deteriorate aspects of chemical, physical, or biological characteristics/quality to such an extent that it impacts its uses and/or ecosystems POLLUTION Can be classified in different ways - Type of pollutants gaseous, liquid, or solid biodegradable, or non-biodegradable physical, chemical or biological  - Type of pollution land, air, or water light, thermal, noise, radioactive, soil, and plastic pollution - Source of pollution agricultural, industrial, municipal and transportation mobile or stationary point source or non-point source - Cause of pollution natural or anthropogenic - Origin of pollution primary or secondary AIR POLLUTION  “Presence of chemicals in the atmosphere in concentration high enough to harm organisms, ecosystems or man-made materials or alter climate“ ATMOSPHERE The thin layer of gases that surrounds the Earth  Consists of several layers  ATMOSPHERE Troposphere ~ 80% earth‘s air mass - N2, O2, H2O(v), CO2, dust, soot , CH4, O3, N2O - determine weather Stratosphere - 24 % earth‘s air mass - less H2O(v) and higher O3 - ozone layer (17-26km) WEATHER AND CLIMATE Weather: conditions of the atmosphere over a short period of time Climate: conditions of the atmosphere over relatively long period of time Microclimate: climate of a very small local area Climate change: a change in the statistical distribution of weather patterns that lasts for an extended period of time WHAT ARE MAJOR AIR POLLUTANTS ? CHARACTERISTICS, CAUSES & IMPACT OF MAJOR AIR POLLUTANTS Pollutant CO C2O NOX SO2 SPM O3 VOCs Characteristics / Nature Sources Impacts SPECIFIC IMPACTS OF AIR POLLUTION Ozone depletion  Acidification  Smog formation  Greenhouse effect  Human health  Ecosystem health  ACID RAIN caused by emissions of CO2, SO2 and NO2 which react with H2O in the atmosphere to produce acids  a rain or any other form of unusually acidic precipitation  possesses elevated levels of H+ ions (low pH).  cause damages to paint to peel, corrosion of metal structures (bridges), and erosion of stone statues/ monuments.  OZONE DEPLETION Ozone keeps about 95% harmful UV rations from reaching the earth surface  A considerable seasonal depletion above the Antarctica (Ozone hole) and Arctic  Lower thinning in every other places also  75 – 80 % depletion is due to persistent CFCs  HCFCs, VOCs, aerosols are the other causes  A serious threat to humans, animals and plants  THREATS OF OZONE DEPLETIONS Health problems Sunburns, skin cancers, more cataracts  Plant life Reduced crop yield, reduced phytoplankton, decreased productivity of UV sensitive plants  Wildlife Reduced populations of aquatic species disrupt food chains, cataracts in some species  Air pollution Degrade plaints & plastics, increased photochemical smog, increased acid rains, enhance global warming  ANTARCTIC OZONE HOLE READ ABOUT  Montreal Protocol in 1987  Copenhegan protocol in 1992 SMOG FORMATION Industrial smog mix of SO2, H2SO4 and solid particles in outdoor air mostly a problem in industrialized areas was a problem in developed countries https://www.youtube.com/watch?v=hN4GhEqtUJ0  Photochemical smog/ brown air smog mix of primary and secondary pollutants under UV radiation (NO & VOCs) NO => NO2 common in many modern cities  HUMAN HEALTH The largest global health risk  The largest environmental health risk ex.  Annually, 7 m deaths and one of every eighth premature deaths  4.3 m deaths from indoor pollutions  3.7 m deaths from outdoor pollutions  GREENHOUSE EFFECT Short Wave Space Incoming Solar Radiation 100 8 Backscattered by air Atmosphere Absorbed by water vapor, dust, O3 Reflected by clouds 19 4 Absorbed by clouds Earth surface Absorbed Reflected by surface 46 17 Long Wave Outgoing Radiation 6 40 9 20 Net emission by water vapor CO2, O3 Absorption of clouds water vapor CO2, O3 Emission by clouds 6 Net Long wave Radiation 15 heat flux 31 RADIATIVE FORCING (RF)  The Earth's surface temperature is determined by the balance between incoming solar radiation and outgoing infrared radiation.  RF the measurement of the capacity of a gas or other forcing agents to affect that energy balance, thereby contributing to climate change the difference between incoming energy absorbed by the Earth and energy radiated back to space + RF : Earth receives more incoming energy from sunlight than it radiates to space. This net gain of energy will cause warming.  - RF : Earth loses more energy to space than it receives from the sun, which produces cooling.  Climate forcing  The influences that cause changes to the Earth’s climate system altering Earth’s radiative equilibrium, forcing temperatures to rise or fall RADIATIVE FORCING OF CLIMATE Source: IPCC 2014  Increased anthropogenic activities since Industrial revolution, caused a positive total net anthropogenic RF due to modification of atmospheric composition.  The increase in the amounts of greenhouse gases causes + RF (IPCC 2014).  Increases in atmospheric CO2 contribute to the greatest RF.  Contribution of other long-lived greenhouse gases (N2O, CH4 & halocarbons) were small but are increasing rapidly. Estimated RF caused by tropospheric ozone is +0.25 to +0.65 W m–2.  However, changes in stratospheric ozone have caused a small negative forcing (–0.05 ± 0.10 W m–2).   Direct natural RF <<<< net anthropogenic RF. TOTAL ANTHROPOGENIC RADIATIVE FORCING Source: IPCC 2014 Based on direct measurements from 1880, the global average surface temperature has increased, especially since about 1950 WARMING TRENDS OVER THE 1951–2010 PERIOD Source: IPCC 2014 GREENHOUSE EFFECT The process in the atmosphere to trap heat  Due to which the Earth’s atmosphere is more than 33 °C warmer than it would be  Name Water vapour Carbon-dioxide Tropospheric ozone Nitrous oxide Methane Others Sum: Effect + 20.6 °C + 7.2 °C + 2.4 °C + 1.4 °C + 0.8 °C + 0.6 °C + 33 °C  Human activities have modified this greenhouse effect by increasing emission of greenhouse gases, which is the most important factor in recent climate change.  Most abundant greenhouse gases Water vapour CO2, CH4, N2O, tropospheric O3 and CFCs TOTAL ANNUAL ANTHROPOGENIC GREENHOUSE GAS (GHG) EMISSIONS ANNUAL GLOBAL ANTHROPOGENIC CO2 EMISSIONS GLOBAL ATMOSPHERIC CO2, N2O & CH4 CONCENTRATION FROM 1850. CONCENTRATION OF CO2 CO2 concentration increased by only 20 ppm over the 8000 years before industrialization  Yearly average concentration of CO2 has increased by almost 40% since industrial times from about 280 ppm to about 390 ppm  Still increasing at an unprecedented rate of on average 0.4% per year  The ice core records suggest a close link between natural atmospheric greenhouse gas variations and atmospheric temperature (IPCC, 2014).  CONCENTRATION OF N2O Concentration of N2O varied by less than about 10 ppb for 11 500 years before the beginning of the industrial era  20% higher than its pre-industrial value.  N2O concentration in 2010 was 324 ppb,  Over the past few decades, the N2O concentration has increased approximately linearly by about 0.8 ppb year–1  Since 1750, N2O concentration has continuously increased due to the increasing anthropogenic emission from agricultural activities and land use change.  CONCENTRATION OF CH4     varied slowly between 580 and 730 ppb over the last 10 000 years, but increased by more than 1 000 ppb in the last two centuries, representing the fastest change over at least the last 80 000 years Current atmospheric level of methane is about 1800 ppb. However, in the last few decades, the rate of increase has slowed increased dramatically since 1750 due to the increasing anthropogenic emissions. CONCENTRATION OF CFC     CFCs and hydrochlorofluorocarbons (HCFCs) are emitted into the atmosphere only during anthropogenic emissions from industrial sources. Their atmospheric concentrations have only been detected since 1950s. As these gases play important role in stratospheric ozone depletion, their emission reduction strategies were declared in the Montreal Protocol for the protection of the ozone layer. Due to the effective reduction of their emissions, atmospheric concentrations are now decreasing by natural removal processes GHG effect is leading to global warming IMPACTS OF GLOBAL WARMING EVIDENCE OF CLIMATE CHANGE        Direct temperature estimations Diminishment in snow cover in the Northern Hemisphere Lessening in icy masses Changes in precipitation ex. more surges, dry seasons and extreme rain Changes in the dates when lakes and streams solidify and their ice softens, Various other natural changes have additionally been observed. Ex. leaf-unfurling, fledgling movement and egg-laying for a few animal varieties. Together these give clear confirmation that the atmosphere is changing DEALING WITH THE THREAT OF CLIMATE CHANGE What can we Do? Prevention ? Clean up ?  THE INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE (IPCC)  Established in 1988 by the United Nations Environment Programme and the World Meteorological Organization  Provides policymakers with scientific information in terms of regular scientific assessments concerning aspects of climate change  3 working groups WGI : science of climate change WGII: impacts, adaptations and vulnerability WGIII: mitigation THE INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE (IPCC)  Published assessment reports 1st Assessment Report 1990 (FAR) 2nd Assessment Report 1995 (SAR) 3rd Assessment Report: 2001 (TAR) 4th Assessment Report 2007 (AR4) 5th Fifth Assessment Report 2014 (AR5)  AR6 PROJECTED CLIMATE CHANGE To predict the expected changes in climate, global circulation model (GCM) simulations are driven by different emission scenarios.  First emission scenarios were produced by IPCC in 1990  Due to the continuous development in understanding of possible future greenhouse gas emissions and climate change, IPCC continue to develop new set of scenarios- SRES,  The next generation of emission scenarios for climate change research and assessment, known as Representative Concentration Pathways (RCPs)  SPECIAL REPORT ON EMISSIONS SCENARIOS (SRES) The SRES cover a wide range of the main driving forces of future GHG emissions  4 different storylines (A1, A2, B1 and B2) assumes a distinctly different direction for future developments (different rates)  A1: Rapid economic growth followed by rapid introductions of new and more efficient technologies  A2: A very heterogenous world with an emphasis on familiy values and local traditions  B1: Introduction of clean technologies  B2: Emphasis on local solutions to economic and environmental sustainability  Sequential approach to development of SRES Parallel approach to development of RCP REPRESENTATIVE CONCENTRATION PATHWAYS (RCPS)      developed in 2007. provided better integration, consistency, and consideration of feedbacks, and more time to assess impacts and responses. based on the projections of RF defined a set of four new scenarios identified by their approximate total RF in year 2100 relative to 1750: a very low forcing level : 2.6 W m-2 for RCP2.6, two stabilization scenarios: 4.5 W m-2 for RCP4.5, 6.0 W m-2 for RCP6.0, very high ghg emissions: 8.5 W m-2 for RCP8.5. ASSIGNMENT Group presentations on following topics based on the AR5 (IPCC 2014)  Observed and projected impacts on ecosystems  Observed and projected impacts on economy  Mitigation and Adaptations  Observed and projected climate change in Asia Time allocation : 15 min Date : READING  Climate climate change impacts on biodiversity and ecosystems in Sri Lanka: A REVIEW by Kottawa-Arachchi in 2017