Storms on the way and the warmest winter on record
Northland could be in for another bout of severe weather over the next 24 hours with MetService predicting strong easterlies, heavy rain and thunderstorms.
A severe weather warning is in place with about 60mm of rain predicted between midday and 6am Sunday. This will intensify in the eastern hills from the Bay of Islands to Whangarei with about 90mm expected there.
Northland is already "soggy" and Metservice forecasters said given those conditions rivers and streams would rise rapidly and flooding was likely in some areas.
Last weekend's storm caused widespread damage, drove families from their homes, cut off some communities and left others without power.
This weekend's heavy rain was expected to spread southwards with a possibility of severe gales around northern Auckland this evening and overnight.
Easterlies could reach gusts of up to 100 km per hour this afternoon before easing tonight. These winds would be followed by southerly gales gusting up to 90km per hour.
WARMEST WINTER ON RECORD
Last year set records for high temperatures around the world, giving New Zealand its warmest winter, and Australia its hottest year since records began.
The warming climate also brought with it droughts, floods and storms - the only silver lining was that Kiwis were a bit less likely to get sunburnt.
Over the past two summers, the ozone hole was smaller, weaker and broke up sooner than in past years, according to the State of the Climate in 2013 report, published yesterday by the United States National Oceanic and Atmospheric Administration.
Warmer air at the South Pole means chlorofluorocarbons (CFCs) do less damage to ozone, the atmospheric material that filters out much of the UV radiation the Earth is bombarded with.
Over winter, clouds form high over the poles and turn CFCs into their active, ozone-degradation forms, National Institute for Water and Atmospheric Research ozone researcher Olaf Morgenstern says.
These clouds last, breaking up ozone, until temperature goes above a certain threshold. "Less of that happens in a warm winter."
Morgenstern said the largest ozone hole was recorded in 2006, and since then it had fluctuated in size.
While not as badly affected by ozone depletion as Antarctica, New Zealand experiences higher levels of UV radiation because of the loss of the ozone layer. With peak UV intensities high, Kiwis have the highest death rate in the world from skin cancer - about 300 a year.
Victoria University climatologist James Renwick, who collaborated on the report, said the conclusions showed the globe was continuing to heat up. While many Kiwis might take comfort in warmer winters, he warned such seasons came hand-in-hand with more severe storms, droughts, floods, and sea level rise.
"You hear about global warming of two or three degrees and you think that's the difference between 9 o'clock in the morning and midday. But what we consider a warm year now will be considered a cold year in future."
Renwick said last year's North Island drought was a warning that the agricultural industry would increasingly feel the pinch. It was adaptable - farmers might swap cold-climate crops such as apples to dry-suited pineapples and bananas - but without significant emissions changes, it was unavoidable, he said.
"In one farmer's working life - if they started out today - by the time they're ready to retire, the climate will be noticeably different."
The compounding effects of global warming were also seen in the destruction of last year's Typhoon Haiyan, noted in the report, when a powerful storm strengthened by warms seas met raised sea levels, Renwick said. "It's like the straw that breaks the camel's back."
BY THE NUMBERS
New Zealand's weather in 2013:
$1.12 billion: The economic impact of the January-April drought.
16.5 degrees: The highest average temperature, for Dargaville. The national average was 13.4.
39 per cent: Of all New Zealand locations had their warmest winter on record.
35.1 degrees: The highest temperature for the year, recorded in Clyde, Central Otago, and Gisborne.
20 per cent: Drop annual rainfall fornorthern North Island and South Island's West Coast.
28,000: Homes lost power in the September 10-11 storm.
200kmh: Gales recorded on Wellington hills during the June 20-21 storm.
600mm: Rain at Tekapo during June storm. The eastern South Island had four times its annual June rainfall.