Jamie Morton is the NZ Herald's science reporter.

Range of climate records broken - report

An unusually high tide at Waimarama Beach. Photo / Hawkes Bay Today
An unusually high tide at Waimarama Beach. Photo / Hawkes Bay Today

A major US report held as the world's most authorative annual climate check has shown a range of records were broken last year - and mostly for the wrong reasons.

The 2012 State of the Climate report, released this morning, found that average temperatures across global land and sea surfaces last year ranked among the 10 warmest years on record.

And it showed New Zealand stood on the edge on an area experiencing the fastest rising sea levels on Earth.

It comes just days after a sobering summary by the Prime Minister's chief science adviser Sir Peter Gluckman, detailing the extreme weather, pests, and impacts on industry that would come as New Zealand climate became 2.1C warmer by 2090.

Globally, land surface temperatures alone were among the 10 warmest on record, while heat content in the upper 700m remained in near record high temperatures.

The report found that heightened hydrological cycles seen over recent years continued, bringing more evaporation to dry areas and more precipitation to rainy areas.

While the number of tropical cyclones and hurricanes was normal, some wreaked massive devastation.

Hurricane Sandy left nearly 285 dead and almost US $70 billion when it slammed into the US east coast in October.

Super Typhoon Bopha, which killed more than 1100 people in the Philippines, was the only storm on record to produce winds greater than 130 knots (230km/h) while so close to the equator.

And following sharp decreases in global sea level in the first half of 2011, thought to have been linked with the effects of La Nina, sea levels rebounded to reach record highs last year.

"The Western Pacific is the place where sea levels have been going up the fastest in the last few years - so we are on the edge of the fastest rising region in the globe," said Victoria University climate scientist Dr James Renwick, a co-author of the report.

Meanwhile, minimum Arctic sea ice extent in September and Northern Hemisphere snow cover extent in June reached new record lows, declining at rates 17 per cent and 13 per cent in the respective months per decade.

Over July 11 and 12, a new melt extent record was recorded at the world's second largest ice body, when 97 per cent of the Greenland Ice Sheet showed some form of melt - four times greater than the average amount for that time.

At the opposite end of the planet, the climate in Antarctica was relatively stable, and the largest maximum sea ice extent on record was observed in September.

Global CO2 emissions from fossil fuel and cement production that reached record levels in 2011 were expected to hit new records in 2012, growing 2.6 per cent to a total 35.6 billion tonnes of CO2.

Atmospheric CO2 concentrations grew by 2.1 parts per million (ppm) in 2012 to 392.6 ppm, and, for the first time, concentrations at seven of 13 Arctic observation sites exceeded the 400ppm milestone.

Other greenhouse gases including methane and introus oxide continued to rise in concentration, while concentration of most ozone depleting substances continued to fall.

"A lot of people like to say that global warming stopped in 1998, and that's said because temperatures have gone up pretty slowly," Dr Renwick said.

"But ice has been melting more rapidly, more heat is going into the ocean and the sea level is rising faster.

"All of those things indicate that the climate system as a whole is continuing to warm up - and warm up faster as we go along."

A wide-ranging overview of climate change in the future is expected within the next few months, when the Intergovernmental Panel on Climate Change reveals its long-anticipated fifth assessment report.

Vital Statistics

* 392.66 parts per million - the projected concentration of CO2 in the world's atmosphere in 2012, a level exceeded in some parts of the globe.
* 35.6 billion tonnes - projected global CO2 emissions from fossil fuel and cement production.
* 97 per cent - a worrying new melt extent record observed at the Greenland Ice Sheet last September, meaning nearly all of the vast body was seen to be melting.
* 285 - people killed when Hurricane Sandy struck the US.
* 2.1C deg - mid-range projections for average temperature rises in New Zealand by 2090.

- NZ Herald

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