A look at weather extremes and the big-picture climate connections.

Australia’s Corals Show Heavy Rainfall May Be Increasing

The Australian summer has now come to an end, and with it the so-called rainy season. But what a wet season it was — remember the floods that inundated Queensland back in early January? In the past 12 months, many parts of Queensland have set their highest rainfall totals on record. But Australian meteorological records only go back about 100 years, which means it's tough to compare recent bouts of heavy rainfall with what the area has seen during the past several centuries.

The past 12 months have seen the heaviest rainfall on record in many parts of the Australian state of Queensland. Credit: Australian Bureau of Meteorology

To put this recent rainfall in the context of long-term climate change, it’s important to go a lot further back in time than a hundred years. The problem is, where to find that data?

Scientists in the rest of the world face the same problem of relatively short instrumental records. Scientists have gotten around this by looking at other parts of the natural world for clues about more ancient climate. For example, scientists can study tree rings to learn about past climate; each ring on a tree tells a story about how humid or dry a year was, and perhaps how hot or cool it was.

Ring by ring, scientists can catalogue the climate conditions that were right where the tree was growing. Tree rings, like ice core samples taken from vast glaciers, are known as "proxy records" because they, in effect, stand in for instrumental records that are missing during a particular time period.

Certain corals can help scientists learn about the climate in a similar way. If you slice open a piece of...

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Extreme Science: Drilling Holes in Arctic Sea Ice

By Helen Findlay, Catlin Arctic Survey Ice Base scientist

This is the first in a series of blog posts from scientists taking part in the third-annual Catlin Arctic Survey

It’s my second time working on the Catlin Arctic Survey, so I feel I know my way around. It’s amazing how quickly you get used to the living conditions. Hanging out our sleeping bags after breakfast to defrost and get rid of all the ice that has formed from our breath during the night takes a good 15 minutes; dragging a sled to “work” every morning and chipping ice out of a hole takes another half hour.

Digging a sample hole through the ice. Credit: Catlin Arctic Survey.

We’ve been sampling through holes cut in the sea ice (which is about 1 meter and 60 centimeters thick). To make them, we had to drill through the sea ice to get to the seawater below. We started drilling using a motorised Mora augur down to about 1 meter 30 cm and then chipped out the remaining ice using ice chisels. As soon as we puncture through to the seawater it begins to gush through the gaps and fill the holes. Within a matter of minutes each hole fills with seawater. It’s hard manual work in the cold conditions (Our first hole was made when temperatures never warmed above minus 35ºC). But hot work too, so sweat starts to freeze when you stop, leaving a layer of frost on my jacket. It may be tough, but working in these conditions means we get to eat as much chocolate and drink as much tea as we like.

It has to have its rewards.

In the first hole we have set up a...

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Live from the North Pole

Last month we told you about a privately funded scientific research expedition that was sending a group of scientists and explorers into the Arctic to learn more about changing environmental conditions there. Now comes word that the third-annual Catlin Arctic Survey has accomplished what may be a television first — conducting a live interview with CNN from only 115 statute miles from the geographic North Pole.

According to the Catlin press office, that is believed to have been the northernmost live television interview in history. In the CNN video (embedded below), explorer and scientist Adrian McCallum discusses the focus of the survey's scientific work, and some of the logistical challenges posed by working in such a harsh region. According to a press release, in order to establish the satellite uplink for CNN, the Survey's operations support team practised rigging the broadcast equipment within a timeframe of just 20 minutes, otherwise cables may have snapped from frigid temperatures.

The Catlin Arctic Survey is sponsored by Catlin Group Limited, an international insurance company. As part of the survey, a small group of intrepid scientists are gathering data on Arctic Ocean circulation and other aspects of the Arctic environment. As my colleague Alyson Kenward wrote in March:

This year, the exploration’s research focus is how all the fresh water melting off Arctic sea ice is influencing ocean circulation, in particular, the thermohaline circulati...

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Doctors’ Group Warns of Health Risks from Global Warming

In an editorial out today, the American Medical Association says doctors in several states are already seeing an increase in climate change-related illnesses, including vector-borne diseases like dengue fever as well as chronic conditions such as asthma. The editorial, published in American Medical News, an online publication, begins with the provocative statement: "If physicians want evidence of climate change, they may well find it in their own offices."

It continues:

Patients are presenting with illnesses that once happened only in warmer areas. Chronic conditions are becoming aggravated by more frequent and extended heat waves. Allergy and asthma seasons are getting longer. Spates of injuries are resulting from more intense ice storms and snowstorms.

The Association cites examples in Florida, where cases of dengue fever, a tropical illness spread by mosquitos that is rarely seen in the US, have been noted recently, and in Maine, where Lyme disease is increasingly common in areas where it had not been prevalent before. The AMA has been leading workshops in these and other states to educate public health authorities about the risks that climate change poses to human health. As the editorial states:

The examples of Florida and Maine show how vector-borne diseases are spreading because of climate change. In Florida, changes in migration patterns and temperatures allow for dengue-infected mosquitoes to circulate. In Maine, warmer and shorter winters me...

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Winter Brings Drought Relief to California

Snow in Squaw Valley, California, in November, 2010. Credit: flickr/climbin.metal

Although many Californians may not have enjoyed the frequent bouts of rain, wind and snow this winter, the parade of storms that have marched in from the Pacific have been beneficial for the state’s strained water resources. So much so, in fact, that Governor Jerry Brown (D) is expected to lift the state's official emergency drought proclamation today, which has been in effect since 2009.

As the New York Times reports, snowpack in the Sierra Nevada mountains is unusually deep, with as much as 50 feet (600 inches) of skier's gold having fallen this winter in some spots. Another news report depicts snow so deep in parts of the Sierras that it is piled as high as power lines. A note on the website of the Squaw Valley resort, a ski area near Lake Tahoe, Calif., indicates the glee that skiers and snowboarders have felt this winter.

Thank you Mother Nature! Squaw Valley has just reached over 50 FEET of total snow accumulation — something that has only happened three times since 1970. Better yet, this is benchmark has never been met before April. Miracle March and an amazing spring are on tap!

The weather pattern this winter was somewhat unusual for a La Niña winter, since La Niña conditions in the equatorial tropical Pacific tend to favor a storm track into the Pacific Northwest that can leave parts of California, particularly southern areas, high and dry. However, as this winter demonstrated, not every La Niña winter behaves the same way.

According...

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