CSIRO climate change modeling has generally concluded that as it gets warmer, it is going to get drier.
I will give two examples:
1. CSIRO News Flash on Monday 15 August 2005 titled 'Natural change, greenhouse effect influence WA rainfall' with the text "Continued rainfall decreases in the south west of Western Australia are most likely a combination of natural variability and the enhanced greenhouse effect". Read more at:
http://www.csiro.au/page.asp?type=mediaRelease&id=145WArainfall
2. CSIRO modeling for Queensland predicts that annual rainfall may decline by as much as 13 per cent by 2030 compared to conditions in the 1990s. By 2070 the decline may be as much as 40 per cent compared to conditions in the 1990s. For more detail see my earlier blog post at:.
But I thought that in past times as the earth got warmer it got wetter?
3. For example, a recent article in ABC Online began:
You would not expect to find a rainforest in what is now one of the hottest and driest places on the east coast of Queensland.
Ancient fossil deposits found in caves near Rockhampton in central Queensland have revealed the area was once a tropical rainforest, wiped out by climate change.
4. According to the IPCC there has been a 0.6C warming over the last 150 odd years and I have interpreted the Australian Bureau of Meteorology (BOM) summaries to show that it has generally got wetter over the last 100 years in Australia.
But I have been told:
Jen, The comment on Australia getting wetter - well you shouldn't really quote national numbers. The centre to north-west may be getting wetter. But everywhere people or major agriculture is located doesn't show this. We have a drier SW WA and east coast drying trend. See ALL the various period maps at: http://www.bom.gov.au/cgi-bin/silo/reg/cli_chg/trendmaps.cgi . We also have had few La Ninas since 1976, more El Ninos and back-to-back "unusual" El Ninos. Few coast crossing cyclones.
So we can quote national figures for everything except rainfall? Because overall it has got wetter, see http://www.bom.gov.au/cgi-bin/silo/reg/cli_chg/timeseries.cgi?variable=rain®ion=aus&season=0112 ?
5. I checked the National Greenhouse Office and they say :
Climate modelling has predicted that on average Australia will get wetter as temperatures rise, especially in summer. Tropical cyclones and floods may become more common, and will happen in places that haven't had them before. However, places such as Tasmania and parts of Western Australia will actually get less rainfall than before, and might even have droughts.
But then they conclude: As temperatures rise and some place get less rain, droughts could happen more often.
6. I remember that the IPCC has written that with climate change, in some areas it will get wetter, in others drier, and I also remember reading that,
7. Australian climatologists have predicted that it will generally get wetter as it gets warmer.
8. I have just read Rod Fensham's new paper in the Journal of Ecology (2005, vol 93,pgs 596-606) titled 'Rainfall, land use and woody vegetation cover change in semi-arid Australian savanna'. The summary includes "... this pattern (changes in vegetation cover in western Queensland) is consistent with the first half of the 20th century having more intense droughts and being drier overall than the relatively wet second half".
So could it get wetter as it gets warmer?
All the hot air on this thread must have significantly increased the global temperature.
Phillip
I noted your comments about 1. phone calls and 2. "summarizing" this thread/having a standing post on climate change.
RE: 1
I have been in Melbourne since Friday and will be here a couple more days. When I get back to Brisbane, and take breathe, I will re-read the CSIRO report for NSW Govt and make the phone call. I don't see an urgency - almost better I plan it as the need arises as I will then be more focused.
RE: 2
I note John Quiggin and other hosters of blogs often summarize threads.
It is not really my style. I don't necessarily need closure on an issue - I know this can be mighty annoying for some people.
I note Malcolm HIll commented that he had learnt from the exchange of comment - that's progress. So have I.
However, if you want to try a summary, it would no doubt be very useful for Malcolm, me and others who have been following this thread.
Send the summary to my yahoo address and I will post it as a new guest 'post' from you as a contributor to this thread etctera. Others can then comment and perhaps in this way we can further refine 'the summary'/'consensus' and have another post on the issue in a week or so.
Well the signs in Australia of drying trends, extended droughts and very fast cyclones in our regions are all food for thought.
But we're something like 1.4% of the world's emissions (correct me if I'm wrong - small anyway) - although among the highest emitters per capita. So even if we turned Australia "off" we're still going to get whatever enhanced greenhouse effects are likely from the rest of the world's emissions.
And the new Asia Alliance led by the USA says we're going to tech our way out !
So wouldn't it be ironic if climate shifts from global warming preferred North America with better rain and extended their wheat belt temperature optimum northwards while there were negative effects in Australia and Africa. Then again God probably likes WASP GOP NRA wheat farmers .... I see the Pope is worried about falling church numbers in Australia... This is the real reason I betcha !