How Human Carbon emissions created Arctic’s balmy Frankenweather

Andrew King | (The Conversation) | – –

For the Arctic, like the globe as a whole, 2016 has been exceptionally warm. For much of the year, Arctic temperatures have been 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.

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

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 will happen for the rest of December. But even with 10 days still to go, it is clear that November-December 2016 will 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.

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.

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, Climate Extremes Research Fellow, University of Melbourne

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


Related video added by Juan Cole:

RT America: “The Arctic warming twice as fast as the rest of planet – NOAA”

One response

  1. Things in life can go downhill fast. Anyone who has been in a car accident knows how quickly disaster can overtake us. Before the accident we have the illusion that all will be well, forever, and that all is under our control. Suddenly, events are completely out of our grasp, we are overtaken by them.
    Something similar happens with an illness or with the onset of old age. Within a very few years, all the systems of the body start to give out, there is no turning back and
    no remedy will reverse the process or substantially prolong life. Before that we had the illusion we’d spend our retirement years traveling, writing, pursuing hobbies; suddenly, we are confined to one place and are in near-constant pain. Then the brain starts going…

    Scientists have been predicting this climate disaster in the making since the late 1800’s, and even their very simple models were not far off at all. Will humankind take any meaningful action at all? And, is it already “too late”?

    Many of us (including all the knowledgeable experts who were not blinded by neocon ideology) predicted disaster with the Iraq invasion, but it happened anyway. A Fukushima-type accident was predictable, and nothing was done to prevent it. Ditto for the collapse of the housing bubble. There are countless examples like this. Given this history, there is realistically very little chance human beings will apply the brakes as we rush toward the climate cliff.

    But things are much worse now:
    the whole of our own species, and all other species, on this
    beautiful planet are at risk. Climate scientists are unanimous in their verdict; the only debate among them now is just how bad it is and how much time we have left. Increasing numbers believe it is already too late to save us. Listen to a lecture by Guy McPherson
    link to
    or go to
    link to
    for the more extreme, but perhaps more realistic, view.
    “Within the Arctic, the Arctic Ocean is warming most rapidly. While the Arctic as a whole was as much as 3.34°C or 6.01°F warmer than in 1979-2000 on December 22, 2016, temperatures over much of the Arctic Ocean were at the top end of the scale that day, i.e. as much as 30°C or 54°F warmer than in 1979-2000.”

    Meanwhile the politicians and fossil fuel executives are much like Trump: in their faith-based world, scientific facts and judgements can be willfully ignored.

    As a result, climate scientists are bullied by those in power to change their conclusions and hide the truth.
    According to McPherson, the talk offstage at climate conferences is very different from the already alarming
    news presented in official talks: people are really seriously worried, and most scientists in this area censor their real opinions, both because of political and hence university or funding agency pressure to conform with a more positive conclusion and because of the usual reticence of careful scientists to announce conclusions that are not (yet) fully supported in a peer-refereed journal article- the traditional scientific standard. But is that standard obsolete when the warnings must be shouted out NOW to the rooftops?

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