The Greenhouse Effect and Climate Change: An Update
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Advice on legislation or legal policy issues contained in this paper is provided for use in parliamentary debate and for related parliamentary purposes. This paper is not professional legal opinion.
Briefing Paper No. 17/2001 by Stewart Smith
The threat of global climate change has produced one of today's most intractable policy issues. This is because the emission of gases that contribute to climate change are currently intricately associated with our everyday lifestyle. Some of the most important conclusions to come out of recent work by the Intergovernmental Panel on Climate Change include: global average surface temperature has increased over the 20th century by about 0.6oC; globally, it is very likely that the 1990s was the warmest decade and 1998 the warmest year in the instrumental record since 1861; snow cover and ice extent have decreased; there has been a widespread retreat of mountain glaciers in non-polar regions during the 20th century; and global average sea level has risen and ocean heat content has increased. However, a few areas of the globe have not warmed in recent decades, mainly over some parts of the Southern Hemisphere oceans and parts of Antarctica (pages 1 - 2).
The IPCC concluded that atmospheric concentration of carbon dioxide has increased by 31% since 1750. The present carbon dioxide concentration has not been exceeded during the past 420,000 years and likely not during the past 20 million years. The current rate of increase is unprecedented during at least the past 20,000 years. About three-quarters of the anthropogenic (ie, human generated) emissions of carbon dioxide to the atmosphere during the last 20 years are due to fossil fuel burning (page 2).
The IPCC projected that globally averaged surfaced temperatures are projected to increase by 1.4 oC to 5.8 oC over the period 1990 to 2100. The projected rate of warming is much larger than the observed changes during the 20th century and is very likely to be without precedent during at least the last 10,000 years (page 3).
The vulnerability of human populations and natural systems to climate change differs substantially across regions and across populations within regions. For Australia and New Zealand, the IPCC noted that the net impact on some temperate crops of climate and carbon dioxide changes may initially be beneficial, but this balance is expected to become negative for some areas and crops with further climate change. Water is likely to be a key issue due to projected drying trends over much of the region and change to a more El Nino like state (page 4).
The international framework for reducing greenhouse gas emissions is based around the United Nations Framework Convention on Climate Change. The Kyoto Protocol is part of this Convention, and commits Australia to limiting greenhouse gas emissions to 108% of 1990 emissions in the period 2008-2012 (pages 13 - 17). However, the Kyoto Protocol is yet to be ratified. The Commonwealth and States have co-operatively developed a National Greenhouse Strategy in an attempt to meet the Kyoto Protocol emission target. The Strategy is divided into eight modules encompassing: profiling emissions; understanding climate change; partnerships; efficient energy use and supply; efficient transport; greenhouse sinks; greenhouse best practice for industrial processes; and adaptation to climate change (pages 18 - 20).
A key response of NSW to reducing greenhouse gas emissions was the establishment of the Sustainable Energy Development Authority in 1996 (pages 20-27).