Are reef fish slowing down as oceans warm up?

Australian study finds warmer ocean temps may be causing problems for coral trout and other large reef fish

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Coral trout may be slowing down as their ocean habitat warms. Photo courtesy Richard Ling, via Wikipedia and the Creative Commons.

By Summit Voice

FRISCO — Warmer water temperatures in the southeastern Pacific Ocean are taking a toll on coral trout, according to a new study from the ARC Centre of Excellence for Coral Reef Studies at James Cook University.

Fish rely on swimming for almost all activities necessary for survival, including hunting for food and finding mates, said Dr, Jacob Johansen, explaining that their research found that global warming may reduce the swimming ability of many fish species, and “have major impacts on their ability to grow and reproduce.” Continue reading

Unraveling the secrets of ocean waves

Satellite tracking helps researcher develop a formula to predict swell decay

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Surfers catch an evening wave at Half Moon Bay, Cailifornia, bberwyn photo.

By Summit Voice

FRISCO — Surfers have long tracked swells across thousands of miles of open ocean to try and predict when the best waves might hit their local beach, and new research by an Australian National University professor may help fine-tune those forecasts.

“Ocean cargo shipping, offshore oil and gas production, and even recreational activities such as surfing, are all dependent on wave action,” said Ian Young, vice-chancellor of ANU. “It is therefore critical that we are able to predict swell.”

Young, who is affiliated with the Research School of Earth Sciences, was interested in determining the rate at which ocean swells decay as they travel across the ocean, so he tracked them with orbiting satellites. The results showed that the decay of the swell depends on how steep the wave actually is.

“Steep waves decay very quickly. However, typical swell is not very steep and can travel across oceanic basins with only a relatively small loss of energy,” he said.

Over 200 individual cases were tracked, making this study the first to provide such comprehensive data of this decay.

“What we were able to do is track the swell from the satellite as it moved from the south to the north, some 1,400 kilometres. We only chose cases where there was no wind so that we could be confident that all we were measuring was the swell decay … We can take these results and put them into a mathematical formula that can be put straight into computer models used by national weather bureaus

“This will increase our ability to better predict wave action. As 70 per cent of the world’s oceans are dominated by swell, it’s extremely important to be able to predict them accurately,” he said.

It is estimated that 75 per cent of waves across the world are not actually generated by local winds. Instead, they are driven by distant storms which propagate as swell.

“For most of the Indian, Pacific and South Atlantic oceans, it is actually the weather in the Southern Ocean thousands of kilometres away that dominates the wave conditions … The Southern Ocean is dominated by big low pressure systems that move across it year round. These systems generate waves that then grow and can travel tens of thousands of kilometres from where they were actually formed, to crash on a beach in Australia.”

Professor Young’s research is published in the Journal of Physical Oceanography.

Study shows how Aboriginal Australians weathered climate change impacts during last ice age

‘Extreme climate change results in the fundamental social and economic reorganization’

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Ice age research offers clues on climate change impacts.

By Summit Voice

FRISCO — The peak of the last ice age, about 20,000 years ago, resulted in huge changes for Aboriginal Australians, who had to deal with expanding deserts, big reductions in rainfall and plummeting temperatures.

“Lakes dried up, forests disappeared, deserts expanded, animals went extinct and vast swaths of the Australian land mass would have been simply uninhabitable,” said Sean Ulm, with James Cook University in Cairns, explaining that the Last Glacial Maximum was the most significant climatic event ever faced by humans in Australia.

To assess how those climatic changes affected aboriginal populations, scientists used advanced geospatial techniques to analyze archaeological radiocarbon dates from across Australia. The research included scientists with the Australian National University and the University of New South Wales, Oxford University in the United Kingdom and Simon Fraser University in Canada. Their findings have been published in the Journal of Archaeological Science. Continue reading

Climate: July global temps 6th-warmest on record

Year-to-date readings also rank as 6th-warmest

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A NASA global temperature map for July shows the widespread pattern of above-average land and sea surface temperatures.

By Summit Voice

FRISCO — The global temperature for July 2013 was 1.10 degrees (all temperatures in Fahrenheit) above the 20th century average, making it the sixth-warmest July on record, according to the National Climatic Data Center.

Nearly every part of Earth reported temperatures well above average with the exception of a few pockets, notably the southeastern and central U.S. and parts of India.

The year to date (January-July) is also ranked as the sixth-warmest on record, with the global land surface temperatures running 1.73 degrees above the 20th century average. Continue reading

Climate: Australian study tries to quantify the role of airborne dust in the global carbon cycle

A 2009 NASA satellite image shows dust blowing off the coast of Africa over the Atlantic Ocean.

A 2009 NASA satellite image shows dust blowing off the coast of Africa over the Atlantic Ocean.

FRISCO — airborne dust, blown off dry ground, is a significant source of atmospheric carbon, according to Australian researchers, who recently set out to try and calculate how that source figures into the global carbon cycle.

Subject to intensifying droughts in some parts of the world, top soil is increasingly being blown away as dust in the wind, changing the amount and location of soil carbon. Some carbon falls back to the ground while some leaves Australia or ends up in the ocean.

Dust also plays a more direct role in regional climate. One recent study led by scientists from the University of Wisconsin-Madison and NOAA suggested that a warming in the tropical North Atlantic was largely due to reductions in airborne dust and volcanic emissions during the past 30 years.

“Carbon stored in our soils helps sustain plant growth. Our modelling shows that millions of tonnes of dust and carbon are blowing away, and it is uncertain where all that ends up,” said Dr Adrian Chappell, of CSIRO, Australia’s national science agency. Continue reading

Global warming: Study finds greenhouse gas fingerprints all over Australia’s record-breaking summer heatwave

Heat-trapping gases increase likelihood of extreme weather

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Australian researchers say there’s a 90 percent chance that unprecedented summer heat was linked with human-caused changes in the atmosphere.

By Summit Voice

FRISCO — Australia’s January heatwave pushed “the limits of previous temperature extremes,” and now, climate scientists are saying they’re more than 90 percent sure that human influences on the atmosphere dramatically increased the likelihood of the extreme summer heat.

Climate scientists have long been saying that global warming loads the climate dice to increase the odds of extreme weather, particularly extreme heat, but they’ve been reluctant to attribute any single event to human-caused climate change.

The findings were announced just as the southwestern U.S. was starting to experience a persistent heatwave that is expected to result in some all-time record temperatures in the region.

The research led by the University of Melbourne shows that global warming caused by heat-trapping greenhouse gases  increases the odds of more record-hot temperatures at least fivefold. The research also suggests that the greenhouse gas fingerprint overpowers, at least in some cases, the influence of the Pacific El Niño-La Niña cycle. Continue reading

Global warming: Hottest summer ever Down Under

Australia, parts of Africa and South America report record-high readings

Six of the hottest ten summers on record have occurred this century, and only two occurred before 1990.

Six of the hottest ten summers on record have occurred this century, and only two occurred before 1990.

By Summit Voice

FRISCO — At the start of meteorological autumn for the southern hemisphere, The Australian Bureau of Meteorology reports that the country recorded its hottest-ever summer season, breaking the 1997-1998 mark by 0.1 degrees Celsius.

The most extreme heat was in the beginning of January, when a heat wave settled across much of Australia, including Tasmania, leading to wildfires and record-high readings in parts of the country, with temperatures soaring as high as 49.6 degrees Celsius (121 degrees fahrenheit). Continue reading

Climate: Australian heatwave sets numerous records

Global warming kicks into high gear Down Under

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Australian heatwave breaks records.

By Bob Berwyn

FRISCO — The New Year is barely a week old, but extreme weather continues, this time in the Southern hemisphere, where parts of Australia reached unprecedented high temperatures, in some cases ranging upward of 120 degrees Fahrenheit. For the sake of comparison, Death Valley reported a reading of 136 degrees way back in July, 1913.

Temperatures during the recent Australian heatwave were so warm that the country’s meteorology bureau added a new color to its temperature-scale map — bright purple, designating readings of warmer than 50 degrees Celsius (129 Fahrenheit). Read the latest update from the bureau here. Continue reading

Rare egg-laying mammal may still live in Australia

Caption: The western long-beaked echidna, one of the world's five egg-laying species of mammal, was thought to be extinct in Australia. However scientists have found evidence that it may still roam the country's north-western region.Credit: Tim Laman


Caption: The western long-beaked echidna, one of the world’s five egg-laying species of mammal, was thought to be extinct in Australia. However scientists have found evidence that it may still roam the country’s north-western region.
Credit: Tim Laman

Closer look at long-lost museum specimen offers new clues into persistence of endangered echidna

By Summit Voice

SUMMIT COUNTY — After re-examining a museum specimen of one of the world’s rarest animals, biologists said they will scour the Australian backcountry to see if they can find a living specimen of the western long-beaked echidna, one of the world’s five egg-laying mammal species.

Until recently, scientists assumed that the critically endangered echidna went extinct in Australia thousands of years ago, but the overlooked specimen in the Natural History Museum in London. was collected from the wild in northwestern Australia in 1901.

Sometimes while working in museums, I find specimens that turn out to be previously undocumented species,” said Kristofer Helgen of the Smithsonian Institution, the lead author and the scientist to first report the significance of the echidna specimen. “But in many ways, finding a specimen like this, of such an iconic animal, with such clear documentation from such an unexpected place, is even more exciting.” Continue reading

Where will 2012 end up in the annals of global warming?

UK temps a hair below average, Australia warmer than normal

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For 2012 to-date, nearly the entire planet saw above average temperatures.

By Summit Voice

SUMMIT COUNTY — While the U.S. is likely be report one of the warmest years ever recorded in 2012, not every country saw record-warmth this year.

The National Climatic Data Center will release the December 2012 and year-end temperature data this week, but several other countries have already released readings, including the UK, which saw a mean annual temperature 0.1 degrees Celsius below the 1981 to 2010 average.

Only 2 years (2010 and 2012) of the last 16 have had annual temperatures below the average. March was the 3rd warmest on record for the UK. The summer was a little warmer than 2011, but otherwise the coolest  since 1998, and it was the coolest autumn since 1993.

The UK Met Office described 2012 as a year of dramatic contrasts, warm and mild the first three months, followed by a shift to exceptionally wet weather from late spring through the summer. Continue reading

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