A Brief Background of the Garnaut Climate Change Study - Assignment Example

 The Garnaut Climate Change Review Introduction This paper gives a brief background of the Garnaut Climate Change Review and a summary of its chapters 4 and 5. The summary outlines the key findings, concepts and recommendations in these chapters. In addition, a review of these findings and recommendations is included. Background On April 30, 2007, the Australian Commonwealth, state and territories governments appointed Professor Ross Garnaut to conduct an independent study examining the effects of climate change on Australia and its economy. The Terms of Reference for the study included evaluation of the impact on Australian “economy, environment and water resources” if no global response to climate change was initiated and also in the case that policy changes did attempt to address the issue (The Garnaut Climate Change Review, 2007). Professor Garnaut was also tasked to suggest the role Australia must play in the international community to mitigate climate change and offer policy options for Australia. The final report was submitted on September 30, 2008. The two chapters of the Review discussed in this paper deal with the three mitigation cases, current and projected climate change of the world in general and Australia in particular. The Review uses IPCC’s Fourth Assessment Report and subsequent research to reach its conclusions and recommendations. Summary of Chapters 4 and 5 and Critical Review Changes observed in the global climate With a small margin of error, the global average temperature has increased by about 0.76 degrees centigrade since the mid 1800s. The rate of increase is not uniform across this period and at all regions of the world. Notably, in the last century, the Arctic temperatures have risen at about twice the average rate in the last century and, since 1979, the rate of increase over land has also been twice that over the oceans. Also, since 1958, the troposphere has been warming faster and the lower stratosphere has cooled substantially indicating the likelihood of effects of greenhouse gases in the troposphere. Oceans, having the capacity to “store thousand times more heat than the atmosphere”, are particularly vulnerable to temperature changes. Since 1955, 80% of the earth’s energy in its climate system can be accounted for by rising ocean temperatures. A direct consequence is a rise in the global mean sea level because of expanding water. The total sea level rise in the 20th century is recorded as 170 mm while that during the years 1993 to 2003 rising at a faster rate of approximately 3.1 mm compared with 1.8 mm for the years 1961 to 2003. The rise is also explained by melting glaciers and ice sheets in non-polar regions, Greenland and Antarctic. In fact, changes in these permanent and seasonal ice layers can cause havoc with regional ecology and climate. For example, the Arctic sea ice level is steadily declining since 1978 creating a chain of actions where less sunlight is reflected back. Regional changes differ owing to several reasons including short term climate effects such as El Nino, rainfall, salt content and currents. While the effects of and on El Nino are still being investigated, changes in salt content caused by changing patterns of rainfall when taken together with temperature changes can affect ocean currents and circulation globally. The level of acidity in the oceans, caused by dissolving carbon dioxide from the atmosphere, is also higher than it has been in the last 420,000 years. In addition to changes in sea levels, ocean currents, melting ice sheets and glaciers, and regional patterns of climate, the increase in temperatures also affects the water cycle. Drier areas get even drier with increased chances of drought and areas near the ocean or water sources get more humid and prone to rain. Annual rainfall statistics show that these changes are already taking place globally. It has also been shown in the IPCC report that extreme weather conditions have been affected, for example, a rise in number of hot days and nights compared with cold days and nights is evident in the last 50 years. Changes observed in Australia’s climate Like global climate data, specific events such as above average cyclone intensities or heat waves cannot be directly attributed to climate change. However, human induced climate change can affect the factors that contribute to such events. In contrast, a rise in average temperature in Australia since the mid 20th century is attributable to human induced influences. Australia being a large continent, this change has not been uniform throughout the country. For example, maximum effects have been recorded in central and south eastern Australia resulting in more severe droughts, changes in rainfall and water availability. Ocean temperatures have also increased particularly in the Indian Ocean. Major changes in rainfall pattern have been seen in the last century but they are not uniform across the continent. These changes in the pattern mostly consist of rates of change in frequency and concentration rather than overall average precipitation. There has been increased rainfall in north west Australia and a decrease in south west, north east and some parts of southern Australia including Tasmania. Declines in rainfall in some regions such as south eastern Australia appear to be affected more by El Nino and other factors rather than climate change alone. Changes in rainfall have caused reduction in streamflows in entire regions within Australia. For example, the Murray Darling Basin has seen a 35 % change in streamflows correlating with a 10 % change in rainfall. The worst affected areas are those around Perth where declines in streamflows have been recorded consistently since 1970 with the current levels only 25 % of the long term average. Other major cities have also been affected with considerable decrease in water supplies owing to reduced streamflows in feeding areas and the reduced levels range from 40% to 65 % of long term averages. Other significant climate changes which have not yet been directly attributed to global warming have been taking place in Australia in recent decades. For example, there has been a record number of El Nino events, the Southern Annular Mode has been more frequently in the positive phase, and there have been a notable increase in sever cyclones in west coast. Also, there have been more bushfires in the east and south east Australia and an increasing intensity of heatwaves. Human influence on climate change Modelling techniques that have included the human related influences on the climate have affirmed that changes in temperature in the 20th century can be explained to a great extent by human influence. Also, increased temperatures over land than ocean, the warming of the troposphere and corresponding cooling of lower stratosphere can be attributed to the increasing greenhouse gases and depletion of the ozone layer. The three emission cases presented by the Review In order to assess the effects of climate change, the Review presents three emission scenarios. For simplicity, these scenarios are based on the most significant human induced climate influence, concentrations of greenhouse gas emissions, and project the resultant effect on the climate up to 2100. The scenarios are: No mitigation case: The assumption is that no effort is made to reduce greenhouse gas emissions. Based on historical data, it is expected that the concentration of greenhouse gases would be 1565 ppm CO2 –e by 2100. 550 mitigation case: It is assumed that efforts are made to reduce emissions and, as a result, the resultant greenhouse gas concentration by 2100 stabilizes to around 550 ppm CO2 –e. 450 mitigation case: More concerted effort would result in stabilization at 450 ppm CO2 –e by 2100. It is noted in the Review that there is a time lag in a change in emissions and its corresponding result on the climate. Any changes in emission starting in 2007 would have a visible effect not before 2030. Projected global climate change for the three emission cases It is important to note that even if greenhouse emissions kept at 2000 levels, there is enough evidence that the average global temperature rise would be 0.6o C by 2100. However, the emission cases consider the growth of world economies and project climate change based on assumption of increased emissions. In the no mitigation case, it is expected that average global temperatures would rise by about 5.1o C by 2100 with a continued high rate of change. Accounting for extreme outcomes in the modelling scenarios, a 6.5o C rise also considered a possible outcome. Regional temperatures and climate outcomes vary and the Arctic temperature can rise above 10o C as melting snow and ice cover would expose darker coloured surface absorbing more heat. In the 550 mitigation case, the average global temperature is expected to rise by about 2.1o C by 2100 and in 450 mitigation case by about 1.6o C with the rate of future change for both being minimal beyond 2100. In both these cases, lesser melting of ice cover at the poles result in relatively restrained regional temperature response. Also, for both mitigation cases, a global long term coordinated effort would be needed while keeping a careful timeline to control emissions of various greenhouse gases like methane, CO2, each having a different effect on warming. A rise in sea levels has strong correlation with rising temperatures. The Review, quoting IPCC, says that without mitigation efforts sea levels may rise between 26 and 59 cm. If models following rapid melting of snow and ice are included the rise could be further by 10 to 20 cm. Between thermal expansion and ice melting, thermal expansion is expected to contribute 70% to 75% to global sea rise by 2100. It must be noted that to initiate a potentially irreversible ice melting process in Greenland, it is estimated that a threshold temperature rise between 1.2o C and 3.9o C relative to 1990 levels is required. This level may be achieved in the 21st century and if this were to happen, sea level rise may go up to 1.5 m, and according to some research, may even cross 6 m. Since ice melting is directly related to temperature rise, the two mitigation cases would have a large impact on ice extents that can be saved. Precipitation patterns are also expected to change with continued global warming. Higher rainfall is expected in equatorial and higher latitude regions while lower rainfall, including drought conditions, are expected in temperate regions. Other outcomes of climate change would include increased ocean acidification, greater intensity of cyclones and larger wave patterns owing to higher wind speeds. The increased acidity and temperature would severly limit the ability of coral reefs to form. Even the highest mitigation case of 450 ppm would not be able to save bio diversity in the reefs. Bio diversity in general would be under threat as it is already under severe strain owing to climate change that has already taken place. While projecting the relatively well-constrained climate outcomes, it is essential that less understood climate phenomena which could have a significant influence on climate change are also considered. For example, El Nino is caused by temperature differentials in ocean water and also causes large changes in heat exchange between water and the atmosphere. Some studies suggest that patterns and intensity of El Nino would change considerably while others suggest there is insufficient data to predict changes. Newer research in coming years may refine the certainty of these predictions. Similarly, it is agreed that, with warming, the ability of oceans to absorb CO2 would decrease. However, how exactly it might result in a climate change outcome and how far it will affect the overall temperature change is not certain. Some of the possibilities include release of methane from ocean bed, release of methane from melting frozen soil cover, and conversion of terrestrial systems such as the Amazon forest from a carbon sink to a carbon source owing to degradation of soil and dying of trees. Finally, certain climate outcomes, though not as severe in their own right, can regionally affect large populations, their economy, large scale displacement or ecological disasters. Such outcomes include the melting of Himalayan glaciers which, according to estimates by WWF, would disappear altogether by 2035 affecting all the major rivers of the Indian sub-continent. The Indian Monsoon could also be affected in consonance with potential changes in El Nino. Though modelling today is limited and cannot accurately predict such changes, a change if it were to happen would affect the economy of the Indian subcontinent greatly. Projected climate change for the three emission cases in Australia Like global temperatures, average temperature up to 2030 remains similar across the three Review cases and is expected to be 1o C above 1990 levels. Beyond 2030, differences emerge and each case produces a different outcome. Also, there is a regional difference in response to each emission pathway. For example, by 2100, in the no mitigation case, the increase in coastal areas is expected to be between 4o C and 5o C, in the 550 ppm case, it would be between 1.5o C and 3o C and, finally, in the 450 ppm case, it would be between 1o C and 1.5o C. In the north west and inland regions of Australia, the average temperature rise would be beyond 5o C in the no mitigation case, between 2o C and 3o C in the 550 ppm case, and 1.5o C and 2.5o C in the 450 ppm case. In terms of rainfall, the overall average rainfall is expected to fall in line with global expectations in the three Review cases with reduction more subdues in the two mitigation cases. However, there are regional variations and some areas may actually experience increased rainfall by 2100. Relative unpredictability in rainfall estimations can also mean there could be extremes in dry or wet spells in the 21st century. It is also possible that rains may be of shorter duration and more intense with longer dry gaps in between. Rainfall pattern changes could affect streamflows, agriculture and infrastructure. It is difficult to predict response in cyclone activity based on global warming alone. However, some studies suggest marked variations in cyclone activity such as decrease in eastern Australian cyclones, increase in force of category 3-5 cyclones, shifting in origin of eastern cyclones southward, and probability of “super cyclones” rising beyond 2050. Heatwaves would be more intense with a marked increase in number of hot days and nights. With incremental increase in average temperatures, the possibility of catastrophic bushfires would correspondingly increase. Critical Review The Garnaut Review followed the Stern Report (Stern, 2006) that came out in 2006 and the IPCC’s Fourth Assessment Report (IPCC, 2007) and, as mentioned in the document itself, included updated research to reach its conclusions and recommendations. In the world of climate predictions where it is still not an exact science the report synthesises this information and offers plausible reasons and probabilities for several potential outcomes and the ways to mitigate their harmful effects. Temperature change projections are made with the highest confidence levels and where outcomes such as severity and direction of precipitation changes do not yet have accurate models for prediction, explanations on basis of recent science are offered in terms of the factors contributing to these outcomes which have a relative certainty of taking place. Unfortunately, two years on, this advantage, of including recent scientific research, has been lost for Australia. Professor Garnaut in his report himself had pointed out that the British Stern Review estimates were outdated and suggested new recommendations in his own report (Adam, 2008). This was only two years after release of the Stern Review. Since the Garnaut Review, there has not been a serious effort to continually reassess climate change implications from the Australian perspective. In the meantime, the government continues to be drawn into delays regarding implementation of the 2008 Garnaut Review of which Professor Garnaut himself expressed concern (Whalley, 2010). One of the assertions in the Review regarding melting of Himalayan glaciers by 2035 was later found out to be inaccurate. Although Garnaut Review was not directly responsible for the mistake as the assertion was quoted from a WWF source in IPCC’s report, this controversy cast a negative light on the validity of the Garnaut Review itself (Nicholson, 2010). However, as IPCC itself pointed out later (IPCC, 2010), this blunder, though embarrassing for the organisation, did not change the overall recommendations for global warming mitigation efforts. Some of the strongest criticism for the Review was related to a parallel consideration and evaluation of the two mitigation cases of 450 ppm and 550 ppm rather than an unequivocal choice. The scientific community and the environmentalists were uneasy with the fact (Mohr, 2008; Australasian Science, 2008) that while the Review stated that the 450 ppm goal was desirable, it gave the government an easier way out by also presenting 550 ppm as an alternate. To be fair, Professor Garnuat himself noted, in chapter 24 of the Review, that the political and economic opinion in the world was perhaps not ripe for a consensus on a 450 ppm target and that taking the 550 ppm pathway would lead to processes coming into place that would eventually make a more ambitious target a possibility (Garnaut, 2008: p. 24). In addition, he expected that the science of climate predictions would continue to improve and it was more important to make a start in the right direction and time would bring more clarity for most stakeholders. Time has at least proven one thing clearly and that is that Professor Garnaut was correct in his prediction that consensus would be difficult globally, let alone within Australia. Regardless of whether his Review’s recommendations were based on pragmatism or real need, the Australian government is still grappling with legislation to implement a watered down emission control scheme. References Adam, D. (2008) Australia's Stern review warns of runaway global warming. The Guardian, 27 October, 2008 [Online] Available from http://www.guardian.co.uk/environment/2008/oct/27/climate-change-australia [Accessed April 12, 2010]. Australasian Science (2008) Scientists Respond to Garnaut's Final Review. Nov/Dec 2008 29(10) p. 12. IPCC (2010) IPCC statement on the melting of Himalayan glaciers. IPCC, 20 January, 2010 [Online] Available from http://www.ipcc.ch/pdf/presentations/himalaya-statement-20january2010.pdf [Accessed April 11, 2010]. IPCC (2007) Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor and H.L. Miller (eds.)]. United Kingdom: Cambridge University Press. Garnaut, R. (2008). The Garnaut Climate Change Review (2007) Chapter 24. The Garnaut Climate Change Review, 30 April, 2007 [Online] Available from http://www.garnautreview.org.au/pdf/Garnaut_Chapter24.pdf [Accessed April 10, 2010]. Nicholson, B. (2010) Garnaut caught in climate panel's Himalayan glacier mistake. The Australian, 5 February, 2010 [Online] Available from http://www.theaustralian.com.au/news/nation/garnaut-caught-in-climate-panels-himalayan-glacier-mistake/story-e6frg6nf-1225826894899 [Accessed April 11, 2010]. Stern, N. (2006) Stern Review on the Economics of Climate Change. HM Treasury Cabinet Office, 30 October, 2006 [Online] Available from http://www.hm-treasury.gov.uk/sternreview_index.htm [Accessed April 11, 2010]. The Garnaut Climate Change Review (2007) Terms of reference. The Garnaut Climate Change Review, 30 April, 2007 [Online] Available from http://www.garnautreview.org.au/terms.htm [Accessed April 8, 2010]. Whalley, J. (2010) Climate expert Garnaut says stop backing outdated industries or .... Geelong Advertiser, 19 March, 2010 [Online] Available from http://www.geelongadvertiser.com.au/article/2010/03/19/156291_news.html [Accessed April 12, 2010]. Mohr, T. (2008). Climate change campaign. Habitat Australia Oct. 2008: 5. Read More