Climate Change and Our Planet
Climate change is one of the most significant social, economic and environmental challenges of our time and has the potential to radically change our business environment, our personal lives, and the ecosystems we rely upon. In a nutshell, climate change is caused by increasing concentrations of greenhouse gases in the atmosphere, which change the planet’s ability to reflect radiation from the sun, resulting in warming of the planet. It’s pretty similar to how the inside of your car warms up when it’s parked in the sun, because the sun’s radiation travels through the glass windows and is trapped in the car.
Our changing climate is predicted to result in warmer global water and air temperatures, modified storm, wind and oceanic current behaviour, sea level rise caused by a combination of warmer water expanding and ice melting, and ocean acidification which, in combination with warmer waters are expected to lead to coral bleaching events. The way these impacts interact is explained with the help of the diagram below.
There is now a large body of evidence indicating that climate change is occurring (IPCC 2007, Figure 1), and that human activity (particularly the releasing of Carbon Dioxide (CO2) into the environment through burning of fossil fuels) is the largest contributing factor (Figures 2 and 3). We are also now seeing changes in ecosystems including modified distribution of species, changes to reproductive patterns, and shifts in foodweb linkages.
Figure 2 Observed changes in (a) global average surface temperature; (b) global average sea level from tide gauge (blue) and satellite (red) data; and (c) Northern Hemisphere snow cover for March-April. All differences are relative to corresponding averages for the period 1961-1990. The shaded areas are the uncertainty intervals estimated from a comprehensive analysis of known uncertainties (a and b) and from the time series (c). (Source IPCC, 2007)
Figure 3 (a) Global annual emissions of man-made greenhouse gases from 1970 to 2004. (b) Share of different man-made greenhouse gases in total emissions in 2004 in terms of CO2-eq. (c) Share of different sectors in total man-made greenhouse gas emissions in 2004 in terms of CO2-eq. (Forestry includes deforestation.) (Source, IPCC 2007)
Figure 4 Changes in surface temperature at both continental and global scales, with results simulated by climate models using either natural causes (blue shaded) or both natural and anthropogenic forcings (pink shaded). Observed temperature data (averaged for each decade) is shown for the period 1906-2005 as black lines (relative to the corresponding average for the 1901-1950). Lines are dashed where spatial coverage is less than 50%. Blue shaded bands show the 5 to 95% range for 19 simulations from five climate models using only the natural influences (solar activity and volcanoes). Red shaded bands show the 5 to 95% range for 58 simulations from 14 climate models using both natural and man-made influences. (Source IPCC 2007)
What does this mean for our oceans and fisheries?
There is currently a lot of research going on to understand the likely implications of climate change for Australia’s fisheries. Two key studies by Hobday et al (2006) and Hobday and Matear (eds) (2005) explain that key impacts will include rising sea level, changes in oceanic currents, changes in ocean chemistry, increasing global temperature, and changing rainfall patterns (both amount and variability). A recent report entitled “Report Card of Marine Climate Change for Australia (2009)” explains that there is already evidence of warming oceans, rising sea leavels (20cm between 1870 and 2004), strengthening of the East Australia Current in eastern Australia, and weakening of the Llewin Current in western Australia, lowering ocean pH by 0.1 since 1750, changes in distribution of species such as the longspined sea urchin in southeastern Australia, reduced growth rate of massive Porites corals on the Great Barrier Reef, and expanding mangrove forests into salt marsh habitats in south eastern Australia.
There is a need to develop a more detailed understanding of the likely impacts specifically for recreational fisheries, and a project is currently being delivered with funding through the Department of Agriculture, Fisheries and Forestry’s Recreational Fishing Industry Development Strategy to provide a better understanding of this, and also to recommend what mitigation and adaptation strategies the recreational sector should consider to deal with likely changes.
Climate Change in Australia – Technical Report, 2007. CSIRO, Australia
Hobday AJ (2006) Impacts of climate change on pelagic fishes. Pages 94-101 in Hobday AJ et al. eds, Impacts of Climate Change on Australian Marine Life: Part C. Literature Review, Report to the Australian Greenhouse Office, Canberra, Australia, September 2006
Hobday AJ, Matear R (eds, 2005) Review of the Climate Impacts on Australian Fisheries and Aquaculture: Implications for the Effects of Change, Report to the Australian Greenhouse Office, Canberra, Australia. December 2005
Hobday, A. J.., T. A. Okey, E. S. Poloczanska, T. J. Kunz and A. J. Richardson (2007). Impacts of climate change on Australian marine life, CSIRO Marine and Atmospheric Research. Report to the Australian Greenhouse Office, Canberra, Australia.
Report Card of Marine Climate Change for Australia (2009) Eds. E.S. Poloczanska, A.J. Hobday and A.J. Richardson, NCCARF Publication 05/09, ISBN 978-1-921609-03-9.
Marine Climate Change in Australia 2009. Impacts and Adaption Responses 2009. 2009 Report Card. CSIRO, Australia.