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Adelaide zoo is hoping to support 34-year-old orangutan Karta through her pregnancy as she has lost six infants in the past

A Sumatran orangutan at Adelaide zoo has fallen pregnant, despite being on contraceptives.

Karta the 34-year-old orangutan is due early in 2017. Jodie Ellen, a senior primate keeper, announced the “exciting but nerve-wracking” news on the zoo’s Facebook page. “It wasn’t a planned pregnancy,” she said. “Mother Nature actually intervened.”

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Sudden changes in output from ageing gas-fired generators may have worsened impact of storms in South Australia blackout, new study suggests. Inverter controlled solar, wind and storage may have ridden through the problems and kept the lights on.

AEMO report cites future of gas-powered electricity generation as “greatest variable” in fortunes of Australian gas industry.

The Minister’s Delegate has approved an update of the names for 7 species.

Sea ice covering the Arctic Ocean during the winter peak in February 2015. NASA's Scientific Visualization Studio

There is no doubt that 2016 has been a record-breaking year for Earth’s climate.

We will have to wait another couple of months for the final tally, but 2016 will be the hottest year in recorded history globally. Average temperatures are well above 1℃ warmer than a century ago.

Global average temperatures, and “global warming”, often give the impression of a gradual change in Earth’s climate occurring uniformly across the planet. This is far from the truth – particularly at the ends of the Earth. The Arctic and Antarctic are behaving very differently from the global picture.

One particular polar change that has caught the attention of scientists and the media this year has been the state of sea ice. The seasonal growth and decay of sea ice over the Arctic and Southern oceans is one of the most visible changes on Earth.

But in the past few months its seasonal progression has stalled, plunging Earth’s sea ice cover off the charts to the lowest levels on record for November. Explaining what has caused this unexpectedly dramatic downturn in sea ice is a tale of two poles.

Global sea ice area (including Antarctica and the Arctic) by year, 1977-2016. National Snow and Ice Data Centre. Wipneus/NSIDC Arctic amplifiers

The northern polar region is an epicentre for change in our warming world.

On average, the Arctic is warming at around twice the global average rate. This is due to several environmental processes in the Arctic that amplify the warming caused by rising atmospheric greenhouse gas levels.

One of these amplifiers is the sea ice itself.

As the climate warms, it’s no surprise that ice melts. What is less obvious is that when bright, white ice melts it is replaced with a dark surface (the ocean or land). Just as a black car parked in the sun will warm up faster than a white one, so the dark surface absorbs more heat from the sun than ice. This extra heat promotes more ice loss, and so the cycle goes.

This can explain the marked long-term decline of Arctic sea ice. But it can’t explain why the past month has seen such a sudden and dramatic change. For this we need to look to the weather.

Arctic climate is characterised by very large natural swings – so much so that in the past few weeks some regions of the Arctic have been a whopping 20℃ warmer than expected for this time of year.

The polar regions are separated from milder equatorial climates by a belt of westerly winds. In the northern hemisphere these winds are commonly referred to as the jet stream.

The strength of the jet stream is related to the north-to-south (cold-to-warm) gradient in northern hemisphere climate. The amplification of warming in the Arctic has reduced this gradient, and some scientists believe that this is allowing the northern jet stream to develop a more meandering path as it travels around the globe.

Jet stream winds in the northern hemisphere, November 11 2016. Screenshot from Global Forecast System/National Centres for Environmental Information/US National Weather Service.

A weaving jet stream allows warm air to penetrate further northwards over the Arctic (the flip side is that extremely cold polar air can also be pulled south over the northern hemisphere continents, causing extreme cold snaps). This appears to be responsible for the current extremely warm temperatures over the Arctic Ocean, which have caused the normal advance of winter sea ice to stall.

In effect, what we are seeing in the Arctic is the combined effect of long-term climate change and an extreme short-term weather event (which itself is probably becoming more common because of climate change).

The southern story

It’s a different story when we look at the ocean-dominated southern hemisphere.

Antarctic climate records point to a delay in some of the effects of “global warming”. The reasons are still debated, partly because of the much shorter climate records that scientists have to work with in the Antarctic.

But it is likely that the expansive Southern Ocean is an important climate change dampener that is able to “hide” some of the extra heat being absorbed by our planet beneath the ocean surface where we don’t feel it – yet.

Unlike the dramatic declines in Arctic sea ice over recent decades, the sea ice that surrounds Antarctica has been increasing slightly over the past three-and-a-half decades and 2014 set records for the most extensive Antarctic sea ice on record. So the decline in Antarctic sea ice since August this year to record low levels has come as somewhat of a surprise.

Again, the weather may hold part of the answer.

The westerly winds that circle the Southern Ocean (analogous to the northern hemisphere’s jet stream) have strengthened and moved closer to Antarctica over the past few decades. One of the effects of this has been to push sea ice away from the Antarctic continent, making for a more expansive coverage across the surrounding ocean.

But the westerly winds are fickle. They are able to change their path across the Southern Ocean very quickly. And so while the southward march in their average position over many years is clear, predicting their behaviour from month to month remains difficult. This spring the westerly winds have tended to sit closer to Australia and out of reach of Antarctica’s sea ice.

What Antarctica’s sea ice will do in the future is still an open question. Climate models indicate that Antarctica won’t remain protected from global warming forever, but just if and when this might cause Antarctica’s sea ice to replicate the Arctic sea ice loss is still anyone’s guess.

Lessons in the madness

Extreme years, such as 2016, are important as they provide glimpses of what the new normal of our climate system may look like in the not-too-distant future.

But these pointers to where we are going also need to be assessed in terms of where we have come from. For sea ice, logbooks from the age of heroic exploration suggest that the Antarctic system is mostly still operating within its normal bounds.

The same cannot be said for the Arctic. The decline of sea ice there has been likened to a ball bouncing down a bumpy hill – some years it will bounce higher than others, but eventually the ball will reach the bottom.

When it does, the Arctic Ocean will be ice-free in summer. That’s a boon for shipping, but don’t expect to see any polar bears on those Arctic cruises.

Nerilie Abram receives funding from the Australian Research Council.

Monash University issues $218m Climate Bond – a world first, targeting sustainable development in the tertiary education sector.

A dramatic drop in the giraffe population over the past 30 years leaves them vulnerable to extinction.

Renewable energy companies are lining up to be part of Renewable Newstead’s bid to lead change in the renewable energy industry.

Transitioning to a fully renewable energy system would be the cheapest option for South America and it is possible in the next 15 years.

From next year Google will purchase 100 per cent of the energy it uses from renewable sources, mostly wind and solar. Because it is cheaper.

Renate Egan has been chosen as part of the Homeward Bound Antarctica voyage; a groundbreaking leadership, strategic and scientific initiative for women.

EnergyAustralia to write contracts for 500MW of wind and solar farm, as solar projects expected to meet half of renewable energy target as costs fall.

Can protest today represent anything more than the venting of emotion and raw discontent? Can it still achieve change?

Not only are public protests today largely impotent, but they dissipate far too quickly because there is no political movement sustaining them. Rather than be enhanced by media coverage, they have become reduced to a media spectacle.

Hydrogen fuel cell cars will take to the streets of Adelaide today in a South Australian first.

Humans may in part owe their big brains to a DNA "typo" in their genetic code, research suggests.

After 250 years, the world finally has an updated, illustrated compendium of the more than 630 known species of rays—stingrays, skates, sawfish, and devil rays—found from the tropics to Antarctic waters.

After 250 years, the world finally has an updated, illustrated compendium of the more than 630 known species of rays—stingrays, skates, sawfish, and devil rays—found from the tropics to Antarctic waters.

Five zoo-born numbats have been released into the Dryandra Woodland in WA.

Two-thirds of those polled in the state seat of Dalrymple think the government should not lend to the Indian mining giant

Two-thirds of voters in the Queensland region that would host Adani’s Carmichael mine think the miner should not be eligible for commonwealth funding, according a new poll.

The ReachTel poll of 544 voters in the state seat of Dalrymple found 66% were against the idea of “an Indian mining company worth over $12bn being eligible for this taxpayer funding towards their Galilee Basin project”.

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