We had better hope Jim Hansen is wrong this time

Former NASA chief climatologist, Jim Hansen has an unfortunate knack of being right a lot more often than he’s wrong. And when it comes to projecting the future path of climate change, he has an equally unfortunate habit of being well ahead of the scientific posse.

Back in the sweltering summer of 1988 Hansen testified to the US Congress on climate change, a phenomenon that was, until his electrifying presentation, seen as something of a scientific curio, an issue that some distant future generation would, eventually, have to confront. Hansen confirmed that not only was it real, it was already happening. Calculations Hansen published in the late 1980s of likely future climate change track what has actually occurred with uncanny accuracy.

Fast forward to 2015, a year in which global temperatures were smashed by record margins to make it, by some distance, the hottest year ever recorded. And temperatures recorded in first two months of 2016 have been described by climate scientists as “off the charts”.

The February 2016 global temperature anomaly is +1.35C above average. It took from the beginning of the industrial revolution until October 2015 to record a +1C global temperature rise. To add another 0.35C within less than six months has left the scientific community running out of superlatives.

And now Hansen is back. He and 19 colleagues have just published a blockbuster paper in the journal Atmospheric Chemistry & Physics. While the IPCC’s assessment reports represent the conservative mainstream view of climate science, Hansen and his colleagues can be said to be at the bleeding edge.

What their research has concluded is profoundly disturbing, throwing into question almost everything we think we know about how climate change is likely to play out in the 21st century. While the IPCC plumped for a likely maximum sea level increase this century of around 1 metre, Hansen argues this may be a hopeless underestimate.

“The models that were run for the IPCC report did not include ice melt, and we also conclude that most models, ours included, have excessive small scale mixing, and that tends to limit the effect of this freshwater lens on the ocean surface from melting of Greenland and Antarctica”, Hansen told a press conference marking the launch of his paper last month.

How Hansen sees this playing out in the real world reads like apocalyptic science fiction. Instead of a slow, incremental increase in sea levels, he believes we are looking at multi-metre sea level rise in the coming decades, not centuries.

Nor will this be a gentle process: he predicts devastating superstorms quite unlike anything since the last Ice Age, and the near-shutdown of major ocean currents such as the Atlantic Meridional Overturning Circulation (AMOC), or the Gulf stream, that vast current of warm tropical water that keeps northwest Europe, including Ireland, from not being frozen solid for several months a year.

If this is beginning to sound familiar, you’re probably thinking of the movie ‘The Day After Tomorrow’, where abrupt climate change triggered a massive freeze in the northern hemisphere. That, of course, is purely speculative; there is already far too much excess heat in the system for the return of widespread Ice Age conditions anytime in the next hundred millennia.

What is truly alarming, according to Hansen, is that as the heat differential between the equator and the northern hemisphere increases, this is likely to fuel powerful mid-latitude storms, on a scale not endured in thousands of years.

Such storms could be powerful enough indeed to pick up massive boulders weighting thousands of tonnes and toss them hundreds of metres inland. We have clear evidence that this has happened before – and he believes it can happen again.

With severe storms battering the world’s coastal regions, compounded by rapid sea level rise, the nightmare scenario of most of the world’s great cities being lost to coastal inundation moves from being some distant spectre far beyond the year 2100 and bang smack into the middle of this century. Cork, Dublin, Galway, Belfast, Limerick, Wexford… the list goes on, and that’s just on this tiny island.

Apart from the unimaginable human misery and forced migration of millions, the economic impact is almost incalculable Most of our critical infrastructure, including all the world’s great ports and trading hubs would be lost.

Not everyone agrees. Prof Peter Thorne of NUIM was among those who reviewed Hansen’s paper, and while not ruling out worst-case scenarios, he believe publicising them may be counterproductive.

“Does this actually confuse, does it cause despair, does it help or hinder? I don’t know whether communicating something like this actually elicits a response that says: let’s do something”, added Prof Thorne.

*This  article is published in the April 2016 edition of Village magazine

ThinkOrSwim is a blog focusing on the inter-related crises involving climate change, sustainability, resource depletion, energy and biodiversity loss
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4 Responses to We had better hope Jim Hansen is wrong this time

  1. Anne Lavin says:

    We Have alot of work to do to wake people up !!!!!!!

  2. John Gibbons says:

    Absolutely right. Hansen has certainly done his share and more as a practising climate scientist to raise red flags in public for almost the last 30 years. Tragic how long it’s taken the system to react to all these dire warnings.

  3. Dr. Daniel Courtney says:

    John,
    Your 2 paragraphs about new records having been set for global temperatures are accurate – by no means do they represent the full story.
    The intervention of a strongly positive El Nino phase in 2015-16 as pushed global average surface temperatures higher than they would have been for ENSO-neutral or La Nina phases ( conditions that usually prevail in the very long time intervals between El Nino events). According to the National Oceanic and Atmospheric Administration (NOAA), the now fading El Nino was in the “very strong” category – one of only 3 in that category since 1951. The 3-month sea surface temperature in the central tropical Pacific of well over 2 degrees Celsius above average during the peak of El Nino 2015-16 indicates that it was comparable in strength to the previous very strong events of 1982-83 and 1997-98.
    The jump in temperature of 0.35 degree C from October 2015 to February 2016 (whilst accurate in a prima facie way) has to be placed firmly in context. Here’s what was going on. Ocean temperatures in the central and eastern tropical tropical Pacific exceeded +2.0 degrees C above average between October 2015 and February 2016 driving increased evaporation. Heat is stored in water vapour which when transferred to higher latitudes condenses as rain or snow and delivers latent heat that brings increased warmth than would otherwise be the case. Incidentally, the figures I use are from two very reputable bodies WMO and NOAA.
    How much of the temperature increase is down to El Nino 2015-16? That is a matter for debate among the scientists. The underlying trend would probably have been upward but nowhere near one-third of 1 degree C across a five months period. As a scientist, I sometimes find that headlines can be simplistic and misleading. You have to be on the lookout for compounding factors and drill down to find the full story.

    Daniel Courtney

  4. John Gibbons says:

    Daniel

    I don’t think we’re disagreeing much at all. There is no doubt the El Nino added to the record-smashing global temperatures in 2015 and the early months of 2016. Carbon Brief have a pretty good analysis of this. They quote Dr Adam Scaife, head of the Met Office’s long-range forecasting division. He suggested only a cursory role for El Niño, telling Carbon Brief:

    “We think El Niño made only a small contribution (a few hundredths of a degree) to the record global temperatures in 2015”. While it’s impossible to get an exact answer to “what if El Niño hadn’t happened?”, scientists can make a reasonable estimate based on examining other El Niño years, explained Scaife.

    Scaife’s view was endorsed by NASA’s Dr Gavin Schmidt. They identify how monthly global temperatures respond during past El Niños and effectively “removing” that signal from the data. Schmidt estimated El Niño was responsible for 0.07C of the above-average warming we saw in 2015. Schmidt’s analysis suggests 2015 would have still been a record-breaking year even without El Niño. After removing the estimated contribution from El Niño of 0.07C, the average global temperature in 2015, according to NASA, would have been 0.8C above the 1951-1980 average, according to the Carbon Brief report.

    I concur entirely that you have to be skeptical and drill down to find the true story. I find the expert opinions of scientists like Schmidt and Scaife quite compelling, and no, I wasn’t just taking Jim Hansen’s ‘outliner’ position at face value – though I did point out that whether you like or loathe him, Hansen’s analysis can not be ignored. He has been right too many times in the past to simply discount his more ‘alarmist’ analysis out of hand.

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