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.

 
 
 
 

“Black cabs are not public transport”: on the most baffling press release we’ve seen in some time

An earlier black cab protest: this one was against congestion and pollution. I'm not making this up. Image: Getty.

You know, I sometimes think that trade unions get a raw deal in this country. Reports of industrial action almost always frame it as a matter of workers’ selfishness and public disruption, rather than one of defending vital labour rights; and when London’s tube grinds to a halt, few people will find out what the dispute is actually about before declaring that the drivers should all be replaced by robots at the earliest possible opportunity or, possibly, shot.

We should be a bit more sympathetic towards trade unions, is what I’m saying here: a bit more understanding about the role they played in improving working life for all of us, and the fact that defending their members’ interests is literally their job.

Anyway, all that said, the RMT seems to have gone completely fucking doolally.

TAXI UNION RMT says that the closure of the pivotal Bank Junction to all vehicles (other than buses and bicycles) exposes Transport for London’s (TfL) symptom-focused decision-making and unwillingness to tackle the cause of the problem.

So begins a press release the union put out on Thursday. It’s referring to a plan to place new restrictions on who can pass one of the City of London’s dirtiest and most dangerous junctions, by banning private vehicles from using it.

The junction in question: busy day. Image: Google.

If at first glance the RMT’s words seem reasonable enough, then consider two pieces of information not included in that paragraph:

1) It’s not a TfL scheme, but a City of London Corporation one (essentially, the local council); and

2) The reason for the press release is that, at 5pm on Thursday, hundreds of black cab drivers descended on Bank Junction to create gridlock, in their time-honoured way of whining about something. Blocking major roads for several hours at a time has always struck me as an odd way of trying to win friends and influence people, if I’m frank, but let’s get back to the press release, the next line of which drops a strong hint that something else is going on here:

TfL’s gutlessness in failing to stand-up to multi-national venture capital-backed raiders such as Uber, has left our streets flooded with minicabs.

That suggests that this is another barrage in the black cabs’ ongoing war against competition from Uber. This conflict is odd in its way – it’s not as if there weren’t minicabs offering a low cost alternative to the classic London taxi before Uber came along, but we’ve not had a lengthy PR war against, say, Gants Hill Cars – but it’s at least familiar territory, so it’d be easy, at this point, to assume we know where we are.

Except then it gets really weird.

With buses stuck in gridlock behind haphazardly driven Uber cars – and with the Tube dangerously overcrowded during peak hours – people are turning out of desperation to commuting by bicycle.

Despite its impracticality, there has been an explosion in the number of people commuting by bike. Astonishingly, 30% of road traffic traversing Bank Junction are now cyclists.

Soooo... the only reason anyone might want to cycle is because public transport is now bad because of Uber? Not because it’s fun or healthy or just nicer than being stuck in a metal box for 45 minutes – because of badly driven Ubers something something?

Other things the cabbies will blame Uber for in upcoming press releases: climate change, Brexit, the outbreak of the Franco-Prussian war in July 1870, the fact they couldn’t get tickets for Hamilton.

It is time that TfL refused to licence Uber, which it acknowledges is unlawfully “plying for hire”.

Okay, maybe, we can talk about that.

It is time that black cabs were recognised and supported as a mode of public transport.

...what?

It is time that cuts to the Tube were reversed.

I mean, sure, we can talk about that too, but... can you go back to that last bit, please?

RMT General Secretary, Mick Cash, said:

“RMT agrees with proposals which improve public safety, but it is clear that the driving factor behind the decision is to improve bus journey times under a buckling road network.

“Black cabs are an integral part of the public transport system and as the data shows, one of the safest.”

This is all so very mixed up, it’s hard to know where to begin. Black cabs are not public transport – as lovely as they are, they’re simply too expensive. Even in New York City, where the cabs are much, much cheaper, it’d be silly to class them as public transport. In London, where they’re so over-priced they’re basically the preserve of the rich and those who’ve had enough to drink to mistakenly consider themselves such, it’s just nonsense.

Also – if this decision has been taken for the sake of improving bus journey times, then what’s wrong with that? I haven’t run the numbers, but I’d be amazed if that wasn’t a bigger gain to the city than “improving life for the people who take cabs”. Because – as I may have mentioned – black cabs are not public transport.


Anyway, to sum the RMT’s position up: we should invest in the tube but not the buses, expensive black cabs are public transport but cheaper Ubers are the work of the devil, and the only reason anyone would ever go by bike is because they’ve been left with no choice by all those people in the wrong sort of taxi screwing everything up. Oh, and causing gridlock at peak time is a good way to win friends.

Everyone got that straight?

None of this is to say Uber is perfect – there are many things about it that are terrible, including both the way people have mistaken it for a revolutionary new form of capitalism (as opposed to, say, a minicab firm with an app), and its attitude to workers (ironically, what they could really do with is a union). The way TfL is acting towards the firm is no doubt imperfect too.

But the RMT’s attitude in this press release is just baffling. Of course it has to defends its members interests – taxi drivers just as much as tube drivers. And of course it has to be seen to be doing so, so as to attract new members.

But should it really be trying to do both in the same press release? Because the result is a statement which demands TfL do more for cab drivers, slams it for doing anything for bus users, and casually insults anyone on two wheels in the process.

A union’s job is to look after its members. I’m not sure nonsense like this will achieve anything of the sort.

Jonn Elledge is the editor of CityMetric. He is on Twitter, far too much, as @jonnelledge.

Want more of this stuff? Follow CityMetric on Twitter or Facebook.