Category: Climate science

Wetter and drier: we did it

The new Nature paper that prompted yesterday’s post on rainfall intensity is covered in detail by the BBC and New Scientist. Rainfall patterns around the globe are shown to be changing in response to increasing greenhouse gases, in line with model predictions. From New Scientist:

Tropical regions north of the equator, including such areas as the Sahel in Africa which borders the Sahara desert, have already begun to get even drier and will continue to do so, the data show. Regions in the far north, including Canada, Northern Europe and Russia, will get wetter, as will the southern tropics.

The magazine also quotes the paper’s lead author, Francis Zwiers of the Canadian Centre for Climate Modelling and Analysis in Toronto, on changes in rainfall intensity:

Zwiers says an important message from the combined models is that they consistently show that, for all regions, there will be a significant increase in extremes of precipitation – both floods and droughts. Thus, even desert areas that will undergo serious drying could simultaneously suffer greater risks of flash flooding. “More or less uniformly across all the models, these extreme events will become more intense just about everywhere,” he says.

Time to reassess flood risks in NZ, perhaps.

Wet times in Blighty, but “Med melts

FishersofmenIf ever there was an image that captures the triumph of hope over adversity, or the stoic nature of the British, it’s this one (credit: BBC/“Andrew in Gloucester

NIWA’s new climate projections coming soon

The Herald managed a sneak peek at NIWA’s latest round of climate projections last week:

Scientists expect New Zealand’s mean temperature will rise by an average 1.8C by the 2080s. By 2100, there will be up to 70 more days with temperatures over 30C, and frosty days will also drop, by five to 20 days in the North Island, and 10-30 days in the South Island. Snowlines will rise and westerly winds will be 20 per cent stronger. Severe droughts are likely to occur up to four times as often, but heavy rain will be more frequent.

Full results will not be available until September at the earliest, but I’m breathing a deep sigh of relief because the new study – based on the global climate modelling used in the IPCC’s Fourth Report – confirms earlier work, and that’s what I used in Hot Topic. Brett Mullen told the Herald:

“You don’t really want to have to reverse what you were saying before, but there certainly were some differences from what we saw in the first assessment. I think we’re on a firmer basis now.

The sun didn’t do it

SunThe last refuge of the climate sceptics is the claim that global warming is nothing to do with us: it’s the sun wot did it (to paraphrase a British tabloid). The claim has never held much water, but the final hole in the sceptics favourite bucket is a new paper examining claims of a solar driver for recent climate change. The BBC reports:

A new scientific study concludes that changes in the Sun’s output cannot be causing modern-day climate change. It shows that for the last 20 years, the Sun’s output has declined, yet temperatures on Earth have risen. It also shows that modern temperatures are not determined by the Sun’s effect on cosmic rays, as has been claimed.

The paper by Mike Lockwood from the UK’s Rutherford-Appleton Laboratory and Claus Froehlich from the World Radiation Center in Switzerland in the Royal Society’s journal Proceedings A, should put the “solar debate

Coast to toast

GeocoverNew Zealand Geographic‘s new issue (#86, July-August) includes a taster of the sort of thing you’re going to get in Hot Topic: the book. I particularly like the graphics created to support my text: the header pic of New Zealand as cheese on toast is spectacular… This article focuses on the science and what it’s telling us. I’ll do a follow-up on how we might cope in due course.