Page 2792 - Week 10 - Tuesday, 14 August 1990
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there is any dispute about that in this day of scientific evidence to that effect. Also it is known that emissions resulting from human activities are substantially increasing the atmospheric concentrations of the greenhouse gases - carbon dioxide, methane, the chlorofluorocarbons and nitrous oxide.
These increases will enhance the greenhouse effect resulting on average in an additional warming of the earth's surface. The main greenhouse gas, water vapour, or steam, will increase in response to global warming and further enhance it, like a dog chasing its tail. Under the IPCC business as usual scenario A, it is forecast that emissions of greenhouse gases will produce an increase of global mean temperature during the next century of about 0.3 degrees centigrade per decade, with an uncertainty range of 0.2 degrees centigrade to 0.5 degrees centigrade per decade. Now, this is greater than that seen over the past 10,000 years. This will result in a likely increase in global mean temperature of about 1 degree centigrade above the present value by 2025 - an increase of about 3 degrees centigrade before the end of the next century.
This rise will not be steady because of the influence of other factors - there is no doubt about that - but under the other IPCC emission scenarios, which assume progressively increasing levels of controls, rates of increase in global mean temperature of about 0.2 degrees centigrade per decade or about 1 degree centigrade per decade are the scenarios that the IPCC has reported on.
The report acknowledges that there are many uncertainties in predictions, particularly with regard to the timing, magnitude and regional patterns of climate change. The report gives the most probable scenario for a climate change, and this is most relevant for planning here in the ACT.
The global mean surface air temperature has increased by 0.3 degrees centigrade to 0.6 degrees centigrade over the last 100 years with the five global average warmest years being in the 1980s. That is indisputable. Over the same period the global sea level has increased by 10 to 20 centimetres. Now, these increases have not been smooth with time nor uniform over the globe. The scientists point out that further information is needed to improve our predictive capability.
In the ACT we need to promote research relevant to our region. I hope that this IPCC Working Group 1 Report gives us a clear perspective into the problem that we are tackling at our local level. There are two types of action we can take. We must act very soon to reduce emissions and we must start thinking about how we are going to adapt to the inevitable changes. Emission reductions will have both economic and social impacts, as well as the beneficial environmental impacts hoped for through the response actions. The Alliance Government will work with the
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