Climate change slides

Major greenhouse gases Greenhouse gas is typically measured in tonnes of carbon dioxide equivalent gases emitted (tCO2-e). There are four major types of greenhouse gas emitted in Australia: Carbon dioxide (CO2), which represents 74.3% of Australia’s emissions and comes primarily from the combustion of fossil fuels Methane (CH4), which represents 20.2% of Australia’s emissions and comes primarily from cattle and other livestock (enteric fermentation), and is also emitted from major waste disposal sites Nitrous oxide (N2O), which represents 4.3% of Australia’s emissions and comes from the production and use of nitrogen fertilizer Chlorofluorocarbons (CFCs), halocarbons and other manufactured gases, which represent 1.1% of Australia’s emissions and are used in refrigeration systems and other manufactured equipment

CO2 concentrations and temperature change This is a slide of some data that Al Gore included in his movie. Two key points - relationship between CO2 concentrations and temperature based on antarctic ice cores and recent direct temperature measurements from Hawaii. While there have been fluctuations in CO2 and temp over the last 400,000 years, current spike in CO2 is beyond the experience of the planet in 10,000 years of human civilisation, and the last 650,000 years of the history of the planet. It is not really surprising to see a spike in CO2 given that it took over 400 million years for the carbon to be sequestered as fossil fuels and a few hundred for humans to release it into the atmosphere Homosapiens last 200,000 yrs Homo habilis 2.5m (stone age) Last glacial period 110,000 to around 10,000 BCE. Currently in an interglacial period since last 11,000 years – coinciding with human civilisation Antarctic temperature is measured as the change from average conditions for the period 1850 CE to 2000 CE

In its 2007 Fourth Assessment Report, the International Panel on Climate Change (IPCC) said there was a >90% chance that observed global warming over the past 50 years is due to anthropogenic GHG concentrations and that this has led to observed changes on many physical and biological systems. Solar and volcanic forces are likely to have produced cooling during this period, and cannot explain the observed temperature trends. Observed patterns of warming and their changes are simulated only by models that include anthropogenic warming. The IPCC is a scientific intergovernmental body established by the United Nations. A main activity of the IPCC is publishing special reports on climate change. The last report involved 2500 scientists from around the world. The UN climate change panel is considered as the definitive reference on climate science. It was the conclusions of the 2007 IPCC Assessment Report which triggered the dramatic increase in attention on climate change over the past two years. The IPCC is tasked to evaluate the risk of climate change caused by human activity. The panel was established in 1988 by the World Meteorological Organisation and the United Nations Environment Program, two organizations of the United Nations. A main activity of the IPCC is publishing special reports on topics relevant to the implementation of the UN Framework Convention on Climate Change (UNFCCC). The IPCC does not carry out research, nor does it monitor climate or related phenomena. The IPCC bases its assessment mainly on peer reviewed and published scientific literature. National and international responses to climate change generally regard the UN climate panel as authoritative and the definitive reference on climate science. The 2007 IPCC fourth assessment report included scientific reviews by 2500 scientists from over 130 countries and with 450 lead authors and 800 contributing authors. The IPCC Assessment Reports are conservative, consensus reports. This is one of the most referenced diagrams from the IPCC fourth assessment report, which shows that climate change is unequivocable and that it is cant be explained by natural mechanisms alone (very likely due to human greenhouse gas emissions) IPCC Fourth Assessment Report 2007

Tasmania’s greenhouse gas emissions Significant increases since 1990 in transport (18%) and energy use in manufacturing industries (35%). Minor decreases in agriculture (3%) and waste sectors (14%). Main changes are in afforestation which has increased carbon capture significantly, (0 to 2.5 Mt) and deforestation which has reduced significantly (27% - 3.6 Mt to 2.6 Mt). National Greenhouse Gas Inventory 2006

What the 2007 IPCC Report says There is now no doubt that the climate system is warming. It is more than 90 per cent certain that humans are the main cause of current global warming. The human-produced greenhouse gases that have already accumulated in our atmosphere will affect our climate for many centuries. If we continue to produce greenhouse gases at or above current rates, it is more than 90 percent certain that climate change will accelerate in the 21st century. It is more than 90 percent certain that extreme events including heat waves and heavy rainfall events will continue to become more frequent.

The 2009 climate science summary IPCC worst case predictions are now being realised Concentrations of greenhouse gases are higher than predicted – especially methane Significant climate change is happening now, and happening faster expected Sea level rise predictions have been significantly revised Climate change will continue for centuries, even if we stop emitting carbon today CO2e emissions (Gt/y) The news from the March 2009 Copenhagen Science Meeting was ‘sobering’. These are some of the main points. Optimistic IPCC scenarios now being ignored Acidification of oceans is bad news for corals and species with carbonate skeletons And sea levels are rising faster than projected as oceans expand and sea ice and ice caps melt. AR4 predicted 18 to 59 cm sea level rise by end of century – Now 1m inevitable by end of century, worst case 1.5m, irrespective of any global action – this is a dramatic change to IPCC predictions. And this is at the conservative end of the spectrum – the minimum change that we can expect. If the Greenland ice sheet and west Antarctica go then we are looking at tens of metres of rise this century. The IPCC predicts a minimum temperature rise by 2100 of 1.8 deg C. About 120,000 years ago when it was 1 to 2 degrees warmer, the sea level was 5 to 8 metres higher – more than enough to inundate many major cities around the world, including Sydney, London and New York. Three million years ago, when the temperature was 2 to 3 degrees higher, sea levels were 25 metres higher. West Antarctica particularly susceptible – 70% increase in melt rate in recent decade. Recent dramatic collapse of ice bridge anchoring the Wilkins Ice Shelf to Antarctica just latest in a series of huge ice sheet collapses off west Antarctic peninsula. Mapping the current greenhouse gas emissions against the IPCC2000 SRES scenarios (Raupach et al., 2007 and Canadell et al., 2007) CDIAC = Carbon Dioxide Information Analysis Center; EIA = Energy Information Administration, both US Department of Energy

Climate change science –take home messages Our current knowledge is not perfect, but we do know: Emissions are growing faster Climate is changing faster Climate will continue to change for decades Risks increase the longer we delay Climate change provides both risks and opportunities for Tasmania.

What's been happening to Tasmania’s climate? Over the past 50 years... Average temperatures have increased by 0.8 to 1.0 degrees, in line with Australian average Minimum temperatures increasing more than maximum Rainfall has declined in most settled areas declines of up to 20mm per decade in the north-west and south-east increases of 5 to15 mm per decade in the south-west. Source: Bureau of Meteorology

What’s likely to happen in the future? Annual maximum temperatures increasing across the state, highest in the north-east Annual potential evaporation increasing in all areas except west coast and highlands where small decreases are predicted Substantial regional variations in rainfall in both quantity and distribution. Currently being modelled by Climate Futures for Tasmania. Rainfall is perhaps the hardest thing to be confident about in the models – CFT are currently working on quantifying that confidence and are not in a position to make any substantial conclusions about the projected changes of rainfall over Tasmania. However, the early indications from their investigations are suggesting that the high-resolution data from the Climate Futures for Tasmania project may uncover more regional variations in the rainfall (both quantity and distribution) than were indicated in the coarse scale global models (wetter in the west, dryer in the east).   Source: CSIRO/Hydro Tasmania/Tasmanian Partnership for Advanced Computing

National Greenhouse Gas Inventory 2006