Weather is not climate (climate is what you expect, while weather is what you get) but bizarre weather can be a sign of a changing climate. In fact, Hansen showed a while ago (see my discussion here) that if the climate is warming, which no reasonable person seriously doubts any more, then we will get more extreme weather events – and you can read ‘more extreme weather events’ two ways, because they will individually be more extreme and there will also be more of them.
This is being borne out very close to home for me. I noted recently that Townsville had had the coldest May day in 22 years. Early this week we had the wettest July day in more than 70 years. The Townsville Bulletin reported that …
More than six times the total average July rainfall was dumped across Townsville in just 24 hours with an average of 89mm clocked from 9am Monday [July 9] to 9am [Tuesday]. More than 40 regions from Bowen to Cairns were drenched with over 100mm of rain …
Daily rainfall records were set along the northern coastline … With 145mm, Innisfail recorded their wettest July day in 125 years while Lucinda totalled 141mm, making it their heaviest rain in 118 years. Burdekin residents also saw record-breaking falls with Home Hill’s wettest July day in 87 years and Ayr’s heaviest falls in 59 years.
Just a little less locally, cane farmers fear another wet winter will reduce their yield and delay their harvest. But wet winters are part of the longer-term climate change on which our extreme weather is superimposed.
The BoM publishes interactive Climate Trend Maps and playing with them is simultaneously kind of fun, instructive and perturbing. Here are some maps to to think about, if you haven’t time to play:
- Queensland annual rainfall, diminishing rapidly along the coast except up around Cooktown – but the *winter* rainfall is actually increasing, although not as much as the annual total is decreasing. Spring rain is not changing much, so the decreased annual rainfall is actually a large decrease in Summer-Autumn (our Wet), partially compensated by a small increase in Spring (on the North coast) and Winter.
- At the same time our maximum temperatures are trending higher in all seasons (click here and toggle through the seasons).
- So are sea surface temperatures, which is one reason coral reef scientists despair about the future of the Great Barrier Reef – e.g. the Statement from the 12th International Coral Reef Symposium in Cairns, 9-13 July 2012.