The IPCC and Climate Change and Causes of Change - Essay Example

? How does the IPCC define climate change? The IPCC refers to climate change as ‘a change in the of the climate that can be identified by changes in the mean and/or variability of its properties, i.e. alteration in earth’s temperatures. Climate Change can persist for an extended period, typically decades or longer. Climate change can be due to: Natural variability – warming or cooling due to sun spot activity, solar radiation Human activity – burning of fossil gases into the atmosphere, causing enhanced greenhouse effect However, there is much debate about what causes climate change, and the UN Framework Convention on Climate Change refers to a change of climate that is attributed directly or indirectly to human activity that alters the global atmosphere. Describe three key findings of the AR4 report that are mentioned in the Introduction Section. Key findings include: 1. An increase in global average air and ocean temperatures, widespread melting of snow and ice and rising global sea levels 11 out of last 12 years from 1995-2006 rank among the 12 hottest years on record Global sea level rise of 1.8mm from 1961-2003 Polar ice caps shrinking – Artic sea ice extent shrank 2.7% per decade Changes in precipitation – decline in Mediterranean, Sahel, southern Africa and increase in eastern part of North and South America, North Europe 2. Natural systems are being affecting by regional climate change, particularly temperature increase Glacial runoff increase glacial lake sizes Hydrological effects – increase runoff, earlier spring peak discharge, warming of lakes/rivers, which effects thermal structure and water quality 3. Effects of regional climate change in natural and human environment are emerging, although many are difficult to discern due to adoption and non climatic drivers Agricultural changes – planting crops earlier on in the year Increase in climatic health hazards, e.g. European 2003 heat wave killed 15,000 people in France What is the difference between natural and anthropogenic drivers of climate change? Provide an example of each. Natural changes refer to climatic alterations in the Earth’s atmosphere that aren’t affected by humans. Astronomical Effects Terrestrial Effects Orbital variability of the Earth Global geometry of continent/ocean distribution Solar storms and flares Ocean tide cycles Sunspot cycles Periodic ocean circulation changes, e.g. El Nino These processes control the amount of suns radiation reaching specific latitudinal zones on Earth Volcanic eruptions Anthropogenic drivers have also been highlighted as contributing to climate change and accelerating the warming of the Earth’s atmosphere. Examples include increased CO? (280ppm from pre industrial levels to 379pmm by 2005), burning of fossil fuels, deforestation, CFC’s and aerosols and from agriculture, e.g. cows releasing significant amounts of methane. What is a greenhouse gas (GHG), and how have their levels changed in the atmosphere changed since 1970? A GHG is a gas in the Earth’s atmosphere that contributes to the greenhouse effect through absorbing and emitting radiation causing climate change. They include CO?, methane, nitrous oxide and halocarbons. Changes in the atmospheric concentrations of greenhouse gases and aerosols, land cover and solar radiation alter the energy balances of climatic systems. There has been a 70% increase in global GHG emissions due to human activities between 1970-2004. CO? annual emissions have increased by 80% from 21 to 38 gigatonnes. CO? also represents 77% of total anthropogenic GHG emissions. Describe the SRES scenarios. What are they, and why do we have more than one of them? SRES refers to the scenarios described in the IPCC Special Report on Emission Scenarios. The SRES project an increase of baseline global GHG emissions by a range of 9.7 to 36.7 GtCO? – eq (25% to 90%) between 2000-2030. The SRES scenarios are grouped into 4 scenario families (A1, A2, B1, B2). They explore alternative development pathways, covering a wide range of demographic, economic and technological driving forces and resulting GHG emissions. The emission projections are widely used in the assessments of future climate change. A1 Divided into 3 groups that describe alternative directions of technological change Fossil intensive (A1FI) Non fossil energy resources (A1T) Balance across all sources (A1B) A2 Very heterogeneous world with high population growth, slow economic development and slow technological change B1 Same global population as A1, but with rapid changes in economic structures towards a service and information economy B2 Immediate population and economic growth, emphasising local solutions to economic, social and environmental sustainability There is more than one scenario because projections of climate change depend heavily upon future human activity, i.e. whether there is population, economic growth or a move towards bioregionalism. Which scenario do you believe is most likely to occur, and why? I believe up until at least 2050 Scenario A1FI is the most likely to occur. This is because the UN predicts that the Earth’s population will grow between 8.5-10.5 billion people by 2050. This scenario also emphasises rapid economic growth, which is now evident in the emerging economies such as China and India. Emphasis on fossil fuels in these areas has already increased over the past decade, and is predicted to intensify over the coming century. By 2100, with an increasingly globalized world, there maybe the possibility of increased social and cultural interaction around the world, leading to the spread of new and efficient technologies. This could possibly curb and decrease GHG emissions. What are two distinct options for responding to climate change? 1. Adaptation refers to the ability of a system to adjust to climate change, both in the short and long term. However, financial, technological, political, social, institutional and cultural constraints limit implementation and effectiveness of adoption measures. 2. Mitigation technologies can help reduce GHG emissions, which are known to cause climate change. However, the widespread diffusion of low carbon technologies may take decades to bring current CO? levels back down to safe levels in the Earth’s atmosphere. Future energy infrastructure investment is also expected to total $20 trillion. Pick two different sectors and describe an adaptation & mitigation strategy for each approach. Which sector are you most concerned about, and why? Sector Adaptation Strategy Mitigation Strategy Energy -Strengthening of overhead transmission and distribution infrastructure -Underground cabling for utilities -Energy efficiency use of renewable resources -Improved supply and distribution efficiency -Switching form coal to gas, nuclear renewable – solar panels, wind farms, tidal power, geothermal energy Water -Expand rainwater harvesting -Water storage and conservation -Water re-use -Irrigation efficiency -Desalination techniques of sea water -Rainfall enhancement techniques, e.g. cloud seed planting from a place -Inter-basin transfers of water -Artificial groundwater recharge I’m most concerned about the water sector because it is predicted that increased climate change will lead to an intensification of the global hydrological cycle, which will have a major impact on water resources over the coming century. In arid regions for example, precipitation is predicted to decrease, leading to major water scarcity. How are humans vulnerable to the impacts of climate change? The risk of extreme weather events, e.g. draughts, heat waves, floods will lead to increased water stress, wild fires, affect food production, health effects and infrastructure damage. There will also be an uneven distribution of impacts and vulnerability, with developing countries feeling the hardest effects of climate change, e.g. scarce water supplies in poor arid countries. Low lying South Pacific Island communities are also under threat from sea level rise, which could destroy their homes, culture and existence. How can we reduce our vulnerability? Adaptation and mitigation strategies must complement each other to significantly reduce the risks of climate change. Reliance of adaptation alone could eventually lead to a magnitude of climate change to which effective adaptation is not possible, or will only be available at very high social, environmental and economic costs. There is an urgent need to stabilize GHG concentrations in order to reduce the more severe impacts of climate change. Low GHG emission technologies would be required for stabilizing, and reducing current GHG emissions. The introduction of large scale renewable energy sources is also crucial in moving towards a more sustainable world. List one robust finding you find interesting and list one robust finding that you think is bogus A robust finding that I find interesting is how continued GHG emissions above current rates will affect regional climates around the world over the coming century. I am interested to see how regional ecosystems adopt to the climatic changes, and how this affects not only the vegetation and wildlife, but how this impacts on the economy, culture and society of a region. For example, in the UK, wine growing is set to increase due to a warmer climate, which will alter the British countryside’s landscape. A robust finding I find bogus, or slightly questionable is that ‘for the next 2 decades a warming of about 0.2°c per decade is projected for a range of SRES emissions scenarios. Whilst I don’t doubt that the world’s temperature is gradually increasing, I believe that the AR4 has not taken the rise in sea levels, which could reduce the effects of the North Atlantic Current due to increased sea water. This could result in reduce temperatures in Northern Europe, rather than a 0.2°c increase. How is climate change analysis uncertain? Provide an example that illustrates uncertainty. A key uncertainty about climate change analysis is that the barriers, limits and costs of adaptation are not fully understood. For example, with regard to water mitigation strategies, de-salinization of sea water appears to be a viable option to provide fresh water in arid regions. However, the cost of implementing and providing such a technology on a large scale is untested and maybe an unfeasible option in many poorer parts of the world (which are the exact areas primarily suffering the worst effects of climate change). Better mitigation strategies must therefore be developed. Word Count: 1,457 (excluding section headings and questions) Read More