Climate change: Cause and impact What is climate change? • Climate change is a change in the statistical distribution of weather over periods of time that range from decades to millions of years. It can be a change in the average weather or a change in the distribution of weather events. Climate change may be limited to a specific region, or may occur across the whole Earth. • Average weather includes all the features we associate with the weather such as temperature, wind patterns and precipitation. Global warming and climate change
The terms 'global warming' and 'climate change' are often used interchangeably, but there is a difference: –Global warming is the gradual increase of the Earth’s average surface temperature, due to greenhouse gases in the atmosphere. –Climate change is a broader term. It refers to long-term changes in climate, including average temperature and rainfall. Greenhouse effect Earth's most abundant greenhouse gases •Carbon dioxide •Atmospheric methane •Nitrous oxide •Ozone •Chlorofluorocarbons •Sulfur hexafluoride •Hydro fluorocarbon •Nitrogen trifluoride Sources of GHGs •Energy Sector –Energy Industry –Manufacturing Industries and Construction –Transport –Residential Sector –Commercial –Agriculture •Industrial processes –Mineral products –Chemical industry –Metal production –Production of halocarbons and sulphur hexafluoride –Consumption of halocarbons and sulphur hexafluoride Sources of GHGs •Agriculture Sector –Enteric fermentation –Manure management –Rice cultivation –Agricultural soils –Prescribed burning of savannas –Field burning of agricultural residues •Waste –Solid waste disposal on land –Wastewater handling –Waste incineration •Landuse Change and Forestry –Conversion of Land –Consumption of Timber and Deforestation Global warming Past 1000 year changes in temperature and
CO2 & CH4 concentrations Ice melting Changes in Gangotri Glacier, Indian Himalaya Cracks in ice bars Physical and socio-economic settings of Bangladesh •Geophysical location makes the country most vulnerable to climate change Impacts –Himalayans in the north –Sea (the Bay of Bengal) in the south with long coast –Vast deltaic floodplain and riverine Charland •Large population with low resource base •High intensity or widespread deep poverty, hunger and food insecurity •Frequent natural and man-made disasters •Poor governance and institutional weakness Climate change impacts •Climate change risks bring additional threat to: –Overall development of the country –Poverty alleviation and livelihood promotion –Sectoral impacts •Human Health impacts –Increase of vector born diseases •Ecosystem Impacts –Coastal wetland loss from sea level rise –Increase of salinity •Agriculture Impacts –Adverse effect on wheat, potato, Boro yield –Loss of agricultural lands •Water Resources Impacts –Increase of drought, intensity of flood and cyclone •Market Impacts –Increase energy demand in winter for heating and summer for cooling •Infrastructure and rural development •Disaster preparedness and risk reduction Climate change impacts in coastal areas §Increasing salinity and water logging §Agricultural land under salt water §Loss of crop diversity and agriculture productivity §Loss of livelihoods and food insecurity §Threat of sea level rise and human displacement §18-20% coastal land will go under water §People will be displaced from their homes and occupations §35 millions people will be displaced by 2050 in Bd. §Rural to urban migration: increasing pressures on cities §International migration: country boundary threatened §Climatic extreme events: cyclones, tidal surge and floods –Super cyclone Sidr and Nargis –Two times floods in 2007 Climate change and food insecurity •Loss of agricultural productivity and crop yields –Temperature rise –Changes in rainfall, hydrological patterns and salinity –Climate extremes: flood and cyclones •Land degradation, water stress and loss of bio-resources •Food Insecurity, malnutrition, hunger and poverty –Poor and marginal farmers are the worst suffers –Women and children are badly hit –Combined effect of climate impacts and social shocks •Demand- supply nexus, market failure and increasing food price •Biofuel product: food versus fuel •Global food price hike and deadly impacts in Bangladesh. IPCC Findings: Observed changes in climate •Warming of the climate system is unequivocal as is now evident from observations: –Increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising sea level •Many natural systems, on all continents and in some oceans, are being affected by regional climate changes •Observed changes in many physical and biological systems are consistent with warming •Global total annual anthropogenic GHG emissions, have grown by 70% between 1970 and 2004 •Most of the global average warming over the past 50 years is very likelydue to anthropogenic GHG emission IPCC Findings: Projections on future climate changes and their impacts •In the current development practices, global GHG emissions will continue to grow over the next few decades •For the next two decades, a warming of about 0.2°C per decade is projected •Continued GHG emissions at or above current rates would cause further warming and induce many changes in the global climate system •Warming tends to reduce terrestrial ecosystem and ocean uptake of atmospheric CO2, increasing the fraction of anthropogenic emissions that remains in the atmosphere •Sea level rise would continue for centuries even if GHG emissions were to be reduced sufficiently Findings: Drivers and projections of future climate changes and their impacts •Equilibrium climate sensitivity is very unlikelyto be less than 1.5°C, but the current century may experience temperature rise of 2°C or more •Major systems, sectors and regions are likely to be especially affected by climate change. The systems and sectors are: –tundra, boreal forest, mountain, Mediterranean-type, mangroves, salt marshes, coral reefs and the sea-ice biome –low-lying coasts, water resources in dry tropics and subtropics and in areas dependent on snow and ice melt, agriculture in low-latitude regions, and human health in areas with low adaptive capacity. –The regions are the Arctic, Africa, small islands and Asian and African mega deltas. Within other regions, even those with high incomes, some people, areas and activities can be particularly at risk. •Impacts would be distributed unevenly: poor and developing countries would be affected most by climate change and climatic events: –Floods, erosion and water logging –Drought and scarcity of water –Cyclone, salinity and sea level rise
The terms 'global warming' and 'climate change' are often used interchangeably, but there is a difference: –Global warming is the gradual increase of the Earth’s average surface temperature, due to greenhouse gases in the atmosphere. –Climate change is a broader term. It refers to long-term changes in climate, including average temperature and rainfall. Greenhouse effect Earth's most abundant greenhouse gases •Carbon dioxide •Atmospheric methane •Nitrous oxide •Ozone •Chlorofluorocarbons •Sulfur hexafluoride •Hydro fluorocarbon •Nitrogen trifluoride Sources of GHGs •Energy Sector –Energy Industry –Manufacturing Industries and Construction –Transport –Residential Sector –Commercial –Agriculture •Industrial processes –Mineral products –Chemical industry –Metal production –Production of halocarbons and sulphur hexafluoride –Consumption of halocarbons and sulphur hexafluoride Sources of GHGs •Agriculture Sector –Enteric fermentation –Manure management –Rice cultivation –Agricultural soils –Prescribed burning of savannas –Field burning of agricultural residues •Waste –Solid waste disposal on land –Wastewater handling –Waste incineration •Landuse Change and Forestry –Conversion of Land –Consumption of Timber and Deforestation Global warming Past 1000 year changes in temperature and
CO2 & CH4 concentrations Ice melting Changes in Gangotri Glacier, Indian Himalaya Cracks in ice bars Physical and socio-economic settings of Bangladesh •Geophysical location makes the country most vulnerable to climate change Impacts –Himalayans in the north –Sea (the Bay of Bengal) in the south with long coast –Vast deltaic floodplain and riverine Charland •Large population with low resource base •High intensity or widespread deep poverty, hunger and food insecurity •Frequent natural and man-made disasters •Poor governance and institutional weakness Climate change impacts •Climate change risks bring additional threat to: –Overall development of the country –Poverty alleviation and livelihood promotion –Sectoral impacts •Human Health impacts –Increase of vector born diseases •Ecosystem Impacts –Coastal wetland loss from sea level rise –Increase of salinity •Agriculture Impacts –Adverse effect on wheat, potato, Boro yield –Loss of agricultural lands •Water Resources Impacts –Increase of drought, intensity of flood and cyclone •Market Impacts –Increase energy demand in winter for heating and summer for cooling •Infrastructure and rural development •Disaster preparedness and risk reduction Climate change impacts in coastal areas §Increasing salinity and water logging §Agricultural land under salt water §Loss of crop diversity and agriculture productivity §Loss of livelihoods and food insecurity §Threat of sea level rise and human displacement §18-20% coastal land will go under water §People will be displaced from their homes and occupations §35 millions people will be displaced by 2050 in Bd. §Rural to urban migration: increasing pressures on cities §International migration: country boundary threatened §Climatic extreme events: cyclones, tidal surge and floods –Super cyclone Sidr and Nargis –Two times floods in 2007 Climate change and food insecurity •Loss of agricultural productivity and crop yields –Temperature rise –Changes in rainfall, hydrological patterns and salinity –Climate extremes: flood and cyclones •Land degradation, water stress and loss of bio-resources •Food Insecurity, malnutrition, hunger and poverty –Poor and marginal farmers are the worst suffers –Women and children are badly hit –Combined effect of climate impacts and social shocks •Demand- supply nexus, market failure and increasing food price •Biofuel product: food versus fuel •Global food price hike and deadly impacts in Bangladesh. IPCC Findings: Observed changes in climate •Warming of the climate system is unequivocal as is now evident from observations: –Increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising sea level •Many natural systems, on all continents and in some oceans, are being affected by regional climate changes •Observed changes in many physical and biological systems are consistent with warming •Global total annual anthropogenic GHG emissions, have grown by 70% between 1970 and 2004 •Most of the global average warming over the past 50 years is very likelydue to anthropogenic GHG emission IPCC Findings: Projections on future climate changes and their impacts •In the current development practices, global GHG emissions will continue to grow over the next few decades •For the next two decades, a warming of about 0.2°C per decade is projected •Continued GHG emissions at or above current rates would cause further warming and induce many changes in the global climate system •Warming tends to reduce terrestrial ecosystem and ocean uptake of atmospheric CO2, increasing the fraction of anthropogenic emissions that remains in the atmosphere •Sea level rise would continue for centuries even if GHG emissions were to be reduced sufficiently Findings: Drivers and projections of future climate changes and their impacts •Equilibrium climate sensitivity is very unlikelyto be less than 1.5°C, but the current century may experience temperature rise of 2°C or more •Major systems, sectors and regions are likely to be especially affected by climate change. The systems and sectors are: –tundra, boreal forest, mountain, Mediterranean-type, mangroves, salt marshes, coral reefs and the sea-ice biome –low-lying coasts, water resources in dry tropics and subtropics and in areas dependent on snow and ice melt, agriculture in low-latitude regions, and human health in areas with low adaptive capacity. –The regions are the Arctic, Africa, small islands and Asian and African mega deltas. Within other regions, even those with high incomes, some people, areas and activities can be particularly at risk. •Impacts would be distributed unevenly: poor and developing countries would be affected most by climate change and climatic events: –Floods, erosion and water logging –Drought and scarcity of water –Cyclone, salinity and sea level rise