Is the Earth Experiencing a Global Warming Spurt?

After almost 15 years of a slowdown in global warming, it appears that the Earth is experiencing an upsurge in the climate phenomenon. 2014 saw record-breaking temperatures all over the globe, which were surpassed last year as global averages reached heights of 1°C above pre-industrial levels.

It was this unprecedented warm spell which brought about a series of natural weather phenomena, including mass floods and torrential thunderstorms.

Experts Blame PDO

Experts on global warming have put the swing down to a flip in the cyclical patterns of the Pacific Decadal Oscillation (PDO), which is also known as the Interdecadal Pacific Oscillation, among other names. This mysterious, slow-moving cycle suffered a phase change in 2014, which leading scientists are linking to the global warming spurt in recent years.

In an attempt to understand this complex and opaque phenomenon, the Guardian newspaper have likened the effects on PDO on the worldwide climate to a staircase. The levelling off period, which has lasted for approximately the last 15 years (and which afforded climate change sceptics the platform to deny its existence) can be seen as a landing of sorts. Now, the PDO has embarked upon a new flight of stairs, leading to a dramatic increase in the effects of global warming over the coming years.

“It seems to me quite likely that we have taken the next step up to a new level,” explained Kevin Trenberth, who was loath to recognise the slowdown period as deserving of that title at all. “The slowdown was not statistically significant, I suppose, if you properly take into account natural variability, which includes the PDO. That’s sort of the argument that people have been making; that even if it was a little bit of a slowdown, or pause, or call it what you will, it’s not out of bounds, and as a result we shouldn’t really put a label on it.”

History Repeats Itself

Scientists have linked the 15-year decrease in temperature hikes to the “cooling down” phase of PDO, which causes the ocean to store more heat in its waters through increased winds. Because the sea levels are absorbing more warmth, airborne temperatures falter. A similar pattern is recognisable between the 1940s and 70s, according to Gerald Meehl, an expert from the National Centre for Atmospheric Research.

“Last time we went from a negative to a positive was in the mid-‘70s,” Meehl explained. “Then we had larger rates of global warming from the ‘70s to the late ‘90s, compared to the previous 30 years. It’s not just an upward sloping line. Sometimes it’s steeper, sometimes it’s slower.”

In the long-term, PDO should have no significant effect upon global warming. That will be dictated by our own energy habits and the carbon footprint we all leave upon the globe, which is why events like the Air Quality Emissions Show 2015 are so important to raise awareness and implement new methods of reducing carbon emissions. However, for the immediate future, the unpredictable cycles of PDO might just make for some predictably warmer weather.