Seasonal Climate Outlook Message for May to August 2008

The bottom line

Neutral SST pattern continues

Neutral sea surface temperatures (SST) now dominate as the 2007/08 La Nina event has weakened. While much of the equatorial Pacific remains slightly cooler than normal, sea surface temperatures closer to the South American coast have shown a gradual warming over the last couple of months.

While at this stage this does not indicate a developing El Nino if this warming SST trend where to extend into the central equatorial Pacific it would be a cause for concern. El Nino SST patterns usually have a negative impact of our expected winter, spring and early summer rainfall.

SST off the Queensland coastline remain cooler than normal. This has the potential to reduce the flow of warm moist air with the south east trade winds. There is a always a better chance of rainfall events to occur when synoptic features such as upper level troughs influence our region if there is atmospheric moisture available.

The SOI has trended downward during May. This is after remaining in a positive SOI phase for several months during last summer and autumn. The thirty day average of the SOI as of 27th May was - 2.8. SOI values look likely to remain near zero through to the end of the month. However if the SOI ends up as a Rapidly Falling SOI phase for May it will have a negative impact on the June - August Outlook.

Updates on the SOI are available on (07) 4688 1623 (seasonal outlook), (07) 4688 1439 (daily updates of 30 day averaged SOI value) or at www.longpaddock.qld.gov.au. You can also receive a text message with the latest SOI values sent to your mobile phone. To subscribe to this free service call Lexie Donald (07) 46881588.

People often ask, "Do I think climate change is 'real'?" My answer to this is yes. Our climate has always changed and will always continue to do so. The real question is about the impact of industrialisation and resulting human induced climate change.

There are two main components of climate change. The first is natural variability which includes shorter terms variations such as seasonal cycles and longer term variations such as onset and retreat of ice ages.

Human influences on our climate include the impact of changing land use, changing urban climates and anthropogenic (manmade) sources of greenhouse gases. These changes can be at a regional scale or on a larger continental/global scale.

So while we do not know at this stage the precise rainfall assessments for Australia under enhanced human induced climate change scenarios the key issue for Australian agriculture and business is that: 'El Niño events are becoming more common' and 'more El Niño-like mean conditions' may prevail in the future (source International Panel on Climate Change 2001 report). This may present a number of challenges to overcome,