Yes, the Arctic’s freakishly warm winter is thanks to man-made climate change

An iceberg breaks off an icesheet near Greenland in 2013. Image: Getty.

For the Arctic, like the globe as a whole, 2016 was exceptionally warm. For much of the year, Arctic temperatures were much higher than normal, and sea ice concentrations have been at record low levels.

The Arctic’s seasonal cycle means that the lowest sea ice concentrations occur in September each year. But while September 2012 had less ice than September 2016, this year the ice coverage has not increased as expected as we moved into the northern winter. As a result, since late October, Arctic sea ice extent has been at record low levels for the time of year.

Late 2016 has produced new record lows for Arctic ice. Image: author provided.

These record low sea ice levels have been associated with exceptionally high temperatures for the Arctic region. November and December saw record warm temperatures. At the same time Siberia, and very recently North America, have experienced conditions that are slightly cooler than normal.

Temperatures have been far above normal over vast areas of the Arctic this November and December. Image: Geert Jan van Oldenborgh/KNMI/ERA-Interim/author provided.

Extreme Arctic warmth and low ice coverage affect the migration patterns of marine mammals and have been linked with mass starvation and deaths among reindeer, as well as affecting polar bear habitats.

Given these severe ecological impacts and the potential influence of the Arctic on the climates of North America and Europe, it is important that we try to understand whether and how human-induced climate change has played a role in this event.

Arctic attribution

Our World Weather Attribution group, led by Climate Central and including researchers at the University of Melbourne, the University of Oxford and the Dutch Meteorological Service (KNMI), used three different methods to assess the role of the human climate influence on record Arctic warmth over November and December.

We used forecast temperatures and heat persistence models to predict what would happen for the rest of December. But even with 10 days still to go, it was clear that November-December 2016 would certainly be record-breakingly warm for the Arctic.

Next, I investigated whether human-caused climate change has altered the likelihood of extremely warm Arctic temperatures, using state-of-the-art climate models. By comparing climate model simulations that include human influences, such as increased greenhouse gas concentrations, with ones without these human effects, we can estimate the role of climate change in this event.

This technique is similar to that used in previous analyses of Australian record heat and the sea temperatures associated with the Great Barrier Reef coral bleaching event.

The November-December temperatures of 2016 are record-breaking but will be commonplace in a few decades’ time. Image: author provided.

To put it simply, the record November-December temperatures in the Arctic do not happen in the simulations that leave out human-driven climate factors. In fact, even with human effects included, the models suggest that this Arctic hot spell is a 1-in-200-year event. So this is a freak event even by the standards of today’s world, which humans have warmed by roughly 1℃ on average since pre-industrial times.

But in the future, as we continue to emit greenhouse gases and further warm the planet, events like this won’t be freaks any more. If we do not reduce our greenhouse gas emissions, we estimate that by the late 2040s this event will occur on average once every two years.

Watching the trend

The group at KNMI used observational data (not a straightforward task in an area where very few observations are taken) to examine whether the probability of extreme warmth in the Arctic has changed over the past 100 years. To do this, temperatures slightly further south of the North Pole were incorporated into the analysis (to make up for the lack of data around the North Pole), and these indicated that the current Arctic heat is unprecedented in more than a century.

The observational analysis reached a similar conclusion to the model study: that a century ago this event would be extremely unlikely to occur, and now it is somewhat more likely (the observational analysis puts it at about a 1-in-50-year event).

The Oxford group used the very large ensemble of Weather@Home climate model simulations to compare Arctic heat like 2016 in the world of today with a year like 2016 without human influences. They also found a substantial human influence in this event.

Santa struggles with the heat. Climate change is warming the North Pole and increasing the chance of extreme warm events. Image: Climate Central.

All of our analysis points the finger at human-induced climate change for this event. Without it, Arctic warmth like this is extremely unlikely to occur. And while it’s still an extreme event in today’s climate, in the future it won’t be that unusual, unless we drastically curtail our greenhouse gas emissions.

As we have already seen, the consequences of more frequent extreme warmth in the future could be devastating for the animals and other species that call the Arctic home.


Geert Jan van Oldenborgh, Marc Macias-Fauria, Peter Uhe, Sjoukje Philip, Sarah Kew, David Karoly, Friederike Otto, Myles Allen and Heidi Cullen all contributed to the research on which this article is based.

You can find more details on all the analysis techniques here. Each of the methods used has been peer-reviewed, although as with the Great Barrier Reef bleaching study, we will submit a research manuscript for peer review and publication in 2017.The Conversation

Andrew King is a climate extremes research fellow at the University of Melbourne.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

Two east London boroughs are planning to tax nightlife to fund the clean up. Will it work?

A Shoreditch rave, 2013. Image: Getty.

No-one likes cleaning up after a party, but someone’s got to do it. On a city-wide scale, that job falls to the local authority. But that still leaves the question: who pays?

In east London, the number of bars and clubs has increased dramatically in recent years. The thriving club scene has come with benefits – but also a price tag for the morning clean-up and cost of policing. The boroughs of Hackney and Tower Hamlets are now looking to nightlife venues to cover these costs.

Back in 2012, councils were given powers to introduce ‘late night levies’: essentially a tax on all the licensed venues that open between midnight and 6am. The amount venues are expected to pay is based on the premises’ rateable value. Seventy per cent of any money raised goes to the police and the council keeps the rest.

Few councils took up the offer. Four years after the legislation was introduced, only eight local authorities had introduced a levy, including Southampton, Nottingham, and Cheltenham. Three of the levies were in the capital, including Camden and Islington. The most lucrative was in the City of London, where £420,000 was raised in the 2015-16 financial year.

Even in places where levies have been introduced, they haven’t always had the desired effect. Nottingham adopted a late night levy in November 2014. Last year, it emerged that the tax had raised £150,000 less than expected in its first year. Only a few months before, Cheltenham scrapped its levy after it similarly failed to meet expectations.


Last year, the House of Lords committee published its review of the 2003 Licensing Act. The committee found that “hardly any respondents believed that late night levies were currently working as they should be” – and councils reported that the obligation to pass revenues from the levy to the police had made the tax unappealing. Concluding its findings on the late night levy, the committee said: “We believe on balance that it has failed to achieve its objectives, and should be abolished.”

As might be expected of a nightlife tax, late night levies are also vociferously opposed by the hospitality industry. Commenting on the proposed levy in Tower Hamlets, Brigid Simmonds, chief executive at the British Beer and Pub Association, said: “A levy would represent a damaging new tax – it is the wrong approach. The focus should be on partnership working, with the police and local business, to address any issues in the night time economy.”

Nevertheless, boroughs in east London are pressing ahead with their plans. Tower Hamlets was recently forced to restart a consultation on its late night levy after a first attempt was the subject of a successful legal challenge by the Association of Licensed Multiple Retailers (ALMR). Kate Nicholls, chief executive at the ALMR, said:

“We will continue to oppose these measures wherever they are considered in any part of the UK and will urge local authorities’ to work with businesses, not against them, to find solutions to any issues they may have.”

Meanwhile, Hackney council intends to introduce a levy after a consultation which revealed 52 per cents of respondents were in favour of the plans. Announcing the consultation in February, licensing chair Emma Plouviez said:

“With ever-shrinking budgets, we need to find a way to ensure the our nightlife can continue to operate safely, so we’re considering looking to these businesses for a contribution towards making sure their customers can enjoy a safe night out and their neighbours and surrounding community doesn’t suffer.”

With budgets stretched, it’s inevitable that councils will seek to take advantage of any source of income they can. Nevertheless, earlier examples of the late night levy suggest this nightlife tax is unlikely to prove as lucrative as is hoped. Even if it does, should we expect nightlife venues to plug the gap left by public sector cuts?