4. Climate Change
Authors: Peter Damerell (Beijing Forestry University), Robert Munroe (BirdLife) & Robin Johnson (BirdLife–CLP)
Climate encompasses temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle count and other meteorological elements in a given region over long periods of time.
The Earth’s climate is changing. 2001-2010 was the warmest decade on record since 1880 and the decade 1991-2000 was the second warmest (United Nations 2011). From 1906 to 2005, temperature has increased, on average, 0.74 °C per year. Correlated with this warming we have seen sea level rise, decreases in snow and ice cover and increased incidence of extreme weather events (IPCC 2007). The Stern Review on the Economics of Climate Change reports that by 2050, 200 million people may have been permanently displaced due to rising sea levels, increased floods and drought (Stern 2006). It is estimated that, since the 1970s, climate change has been responsible for over 150,000 deaths each year (McMichael et al. 2004).
A 1 °C increase in global temperature could easily double this figure (Patz et al. 2005). The principal drivers of climate change are variations in atmospheric concentrations of greenhouse gasses (GHG, including water vapour, carbon dioxide, methane, nitrous oxide, and ozone) and aerosols, as well as changes in land cover and solar radiation, all of which alter the energy balance of the Earth’s climate. Terrestrial and marine ecosystems currently sequester carbon, acting as ‘sinks’. Changes to atmospheric CO2 concentrations could shift the global carbon cycle towards annual net emissions, turning these ecosystems into ‘sources’. Concentrations of other greenhouse gasses, including CH4 and N2O, which have similar effects, have also increased markedly as a result of human activities.
Continued GHG emissions at or above current levels will cause further warming and induce global climate change during the 21st century, very probably greater than that observed during the 20th century (IPCC 2007).
The basic mechanisms of the atmospheric ‘greenhouse effect’ are:
- sunlight passes through the atmosphere and heats the Earth’s surface;
- the heated surface then cools by emitting infrared radiation into the atmosphere;
- most of this radiation is absorbed by greenhouse gases in the atmosphere, some of which is re-radiated back towards the ground and some into space.
The overall effect is to reduce the rate at which the Earth loses heat to space, making the surface and lower atmosphere warmer than they would otherwise be. IPCC (2007) predicts the average global temperatures are likely to rise between 1.1 and 6.4 °C (best estimates of 1.8 to 4 °C) above 1990 levels by the end of the 21st century, depending on our future greenhouse gas emissions. Projected changes in the temporal and spatial distribution of precipitation will see current local patterns exacerbated. Such changes would have profound negative impacts on biodiversity and associated ecosystem services, some of which are outlined in Chapter 7. Assessment Report (AR) 4 from the Intergovernmental Panel on Climate Change (IPCC) describes key risks, including (IPCC 2007):
- A rise of 3 °C or more will result in significant loss of forest towards the end of the century, with serious implications for associated biodiversity.
- Higher temperatures are likely to result in changes to the plankton communities upon which whole inland aquatic ecosystems depend.
- These changes will impact on the many people who derive their livelihoods from such environments.
The United Nations Framework Convention on Climate Change (UNFCCC) sets a context for intergovernmental efforts to tackle climate change and recognizes the Earth’s climate system as a shared resource. The Kyoto Protocol, part of the UNFCCC, sets binding targets for 37 industrialized nations and the European Community for reducing their GHG emissions (UNFCCC 2011). This agreement will be extended until at least 2017. To replace it, 194 countries at the UN Climate Change Conference in Durban, November 2011, agreed to develop a legally binding mechanism by 2015, to come into force in 2020.
Emissions in 2008 were 38% higher than those in 1990; a total of 30.1 billion tonnes of CO2 have been emitted since this baseline year (United Nations 2011). An increase above 2-3 °C is very likely to trigger substantial changes in the structure of ecosystems and their ability to function (IPCC 2007) (further details are given in Chapter 7). However, the emission reduction pledges made by participant countries at the Conference of the Parties in Cancun during 2010 would still result in a global temperature increase, by 2100, of at least 3.9 °C (Climate Interactive 2011). Even with successfully implemented climate change mitigation policies, significant change is inevitable due to lagged responses in the Earth’s climate system.
The IPCC is currently compiling AR5 (for progress, see http://www.ipcc.ch/activities/activities.shtml), which will place greater emphasis on the socio-economic aspects of climate change and implications for sustainable development.
Climate change is an issue that must be simultaneously tackled at all scales, by all parts of society. It is likely, for example, to challenge the realisation of sustainable development, including the Millennium Development Goals, by reducing the livelihood assets of vulnerable people and by impacting on natural resources.
Livelihood loss: Lohachara Island, once home to 10,000 people, has succumbed to rising sea levels. In 2007 residents of Papua New Guinea’s Cateret Islands were evacuated to nearby Bourgainville. Both of these were ‘intra-state migrations’, whereas threatened island states such as Tuvalu, Kiribati, the Marshall Islands and the Maldives will require a different approach. In addition to the question of ‘climate refugees’, this raises issues of access to and benefit from marine resources (Rayfuse 2009).
Phenological response: A comprehensive review of phenological records, from 21 European countries spanning 1971-2000 showed conclusive evidence of the increasingly early arrival of spring and summer, and that the biological responses that underpin this finding are undoubtedly linked to observed temperature trends. These responses were exhibited by a wide range of taxa, encompassing 542 plant and 19 animal species (Menzel et al. 2006).
- What changes in climate patterns are expected in your part of the world within the next 50 years?
- How do members of your community perceive the threat of climate change?
- How do they expect their lives and livelihoods to be affected?
Climate Interactive Scoreboard - Uses simulation models to calculate the long-term climate impacts of proposals under consideration in the UNFCCC process.
Climate Interactive C-Roads - Decision-maker-oriented simulation that helps users understand the long-term climate impacts of scenarios to reduce GHGs emissions.
Tyndall Centre for Climate Change Research - Includes the latest research, podcasts and news on climate research.
WorldClim - A set of global climate data layers with a spatial resolution of a square kilometre. They can be used for mapping and spatial modelling in a GIS or other computer programs.
World Meteorological Organisation - Gives general climate projections with regional patterns.
World Resource Institute’s Climate Analysis Indicators Tool (CAIT) - An information and analysis tool providing data on greenhouse gas emissions, sinks, sources and other indicators.
Climate Interactive, 2011. The Climate Scoreboard. [online] Available at: <http://climateinteractive.org/scoreboard> [Accessed 01 December 2011].
IPCC, 2007. Climate Change 2007: Synthesis Report. Contribution of Working Groups I, II and III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team]
McMichael, A.J., Campbell-Lendrum, D., Kovats, S., Edwardsm S., Wilkinson, P., Wilson, T. 2004. Global Climate Change. In: Ezzati, M., Lopez, A., Rodgers, A. and Murray, C.J.L., eds. Comparative quantification of health risks: global and regional burden of disease attributable to selected major risk factors. Geneva: World Health Organization, pp.1543–1650.
Menzel, A. , Sparks, T.H., Estrella, N., Koch, E., Aasa, A., Ahas, R., Alm-Kübler, K., Bissolli, P., Braslavská, O. and Briede, A., 2006. European phenological response to climate change matches the warming pattern. Glob. Change Biol., 12, pp.1969–1976.
Pachauri, R.K and Reisinger, A. (eds.)]. IPCC, Geneva, Switzerland, 104 pp.
Stern, N., 2006. Stern Review on the Economics of Climate Change. UK Government Economic Service, London.
Patz, J. A., Campbell-Lendrum, D., Holloway, T. and Foley, J. A., 2005. Impact of regional climate change on human health. Nature, 438 (7066), pp.310-317.
Rayfuse, R., 2009. W(h)ither Tuvalu? International Law and Disappearing States. University of New South Wales Faculty of Law Research Series. University of New South Wales Faculty of Law Research Series. Working Paper 9.
United Nations, 2011. The Millennium Development Goals Report 2011. New York.
United Nations Framework Convention on Climate Change (UNFCCC), 2011. Kyoto Protocol. [online] Available at: <http://unfccc.int/kyoto_protocol/items/2830.php> [Accessed 11 January 2012]