La Nina likely to develop in the Pacific by December, Bureau of Meteorology says

A La Nina is almost certain to develop in the Pacific this summer, as all eight models used by the Bureau of Meteorology anticipate threshold levels for the key climate pattern will be reached or exceeded by next month.

The bureau's latest fortnightly assessment of conditions in the Pacific and Indian oceans rates the likelihood of a La Nina this summer at about 70 per cent – triple the usual level – prompting it to issue a La Nina alert on Tuesday.

During La Nina years, eastern Australia tends to have wetter than usual summers, as equatorial trade winds strengthen, shifting rainfall westwards.

While the added cloud cover can moderate temperatures, there is also an increased chance of prolonged warm spells for south-eastern Australia during La Ninas, the bureau says. The cyclone season can also be more active than usual.

Read Peter Hannam’s story in today’s Melbourne Age - “La Nina likely to develop in the Pacific by December, Bureau of Meteorology says.”

One of the oldest climate change experiments has led to a troubling conclusion

One of the regular complaints of climate change doubters and skeptics is that scientific projections of a dire future are too heavily based on computer simulations, or models, which — they say — rest on a variety of questionable assumptions.

Heated and control plots in a long-term soil
 warming study at Harvard Forest, Petersham,
Mass. Jerry Melillo of the Marine Biological
 Laboratory, Woods Hole, Mass., and colleagues
began the study in 1991. 

But a major climate change study published Thursday relied not on models but experimental data — a 26-year record of observations, no less — to reach a conclusion perhaps just as worrying. The research, tracking the emissions of carbon from artificially heated plots of a forest in Massachusetts, reinforces fears about the possibility of a climate change “feedback” involving the planet’s soils, one that could pile on top of and substantially worsen the ongoing warming trend triggered by the burning of fossil fuels.

“The study is one of the longest if not the longest climate change ecosystem experiment, beyond the one we are running in our own planet,” said Pep Canadell, an expert on the Earth’s carbon cycle at the Commonwealth Scientific and Industrial Research Organization in Australia. He was not part of the research.

Read Chris Mooney’s story on The Washington Post -  “One of the oldest climate change experiments has led to a troubling conclusion.”

CSIRO models help us quench of thirst for knowledge about the future

W

e all have an interest in whether rain will dampen our day and a curiosity about what the skies hold for next week. We are all impacted when the weather turns extreme, sometimes in devastating ways. And we have a yearning to know what the future might hold for our climate, so that we can plan ahead.

Weather and climate may never be completely predictable, but science has come far enough for us to be breaking new ground when it comes to projecting what Australia’s climate may look like decades – or even hundreds of years – in the future.

And here’s a sneak peak into the future – by the year 2090, Sydney could have the climate of Brisbane, and Melbourne could have the climate of Dubbo.

Read more of what Chris Gerbing has to say in “Australia’s Next Top climate models”.