Bruce Bisset: Reality bites over climate

Last year's record highs included the hottest June in New Zealand. Photo / Thinkstock

News that 2014 was the hottest year on record should finally put to bed the false theory climate sceptics have been disseminating that the Earth's temperature rise has "paused", or even reversed; a lie they've used to attack projections of further warming as unsupportable.

Their argument was founded on an anomaly: 1998, thanks to a strong El Nino effect, was significantly hotter than any other year since continuous verifiable records began in 1880. So when following years were not quite so hot, sceptics claimed global warming had stopped.

It is a classic piece of cherry-picking, but it conveniently ignores that 12 of the hottest 15 years on record have occurred since.

Frankly, the "pause" theory was based on ignorance of data trends and of the impact of major climate drivers. Anyone failing to understand that the Pacific El Nino (hotter) and La Nina (colder) weather patterns dramatically affect temperatures in the years in which they occur is neither qualified nor informed enough to comment.

Of note is that unlike in any of the other three recent record years, 2014's high thermometer readings came in a "neutral" year, when neither the El Nino nor La Nina patterns were operating.

And when overall data is broken out into those three categories, the moving average rise for each from 1965 until now mirrors the others. In short, it shows that whether a "hot", "neutral", or "cold" year, temperatures continue to rise.

Overall temperatures have risen about 0.7 of a degree C since 1965, and the projection of at least 2 degrees of warming this century is well within the trending average. When other "follow-on" factors such as permafrost methane release and "saturation" level for sea surface temperatures are extrapolated into account, 2100 could be more than 4C degrees hotter than globally today.

That still may not sound a lot, but chances are we will have opportunity to experience something of that rise this year, with an El Nino pattern expected to assume control of Pacific weather. Even a mild effect should, science predicts, make 2015 the new high-temperature record-holder.

Yep, it's hot and it's only going to get hotter.

Note that I am not arguing cause, here. I am simply stating fact.

Last year's record highs included the hottest January in Argentina, February in Finland, March in Slovenia, May in South Korea, June in New Zealand, July in Norway, and the season of spring in Australia. As well as the warmest ever sea surface temperature, globally, in September.

The real kicker though is not temperature rise itself, but the flow-on effects it causes. Chief among those, as far as humans are concerned, is probably sea-level rise.

The world's oceans are expected to rise around one metre this century - and that's a conservative estimate, with some models predicting a rise of three metres, depending on how much the polar ice sheets melt.

And they're melting increasingly quickly and irreversibly according to recent data.

Moreover, while New Zealand may escape with a lower temperature rise than elsewhere, our shorelines will suffer about 10 per cent greater impact.

That's the thing with global averages; what you get depends very much on where you are.

Of course this news has seen little media exposure and less political comment; climate change is the elephant no one wants to deal with. But the fact the 2014 heat record made the front page of the New York Times indicates that maybe, despite the scepticism, reality is starting to bite.

Bruce Bisset is a freelance writer and poet.