Not so hot as it is portrayed!

Hot Hot Hot!    2016 Hottest Year on Record.  New Zealand had its hottest ever recorded year in 2016.

These were some of the media headlines following the release of NIWA’s Annual Climate Summary last week.

Many will think that it’s great to have a hot hot hot summer.  By the pool, at the beach, hot is great!  What’s the problem?  After all, pool and beach images celebrating hot, frames many of the media reports on the conference.  So good it has to be!  Right?

Wrong!

The problem is that for New Zealand, 2016 was the hottest in a series of ever hotter years. Since 1909, annual average temperatures across the country have risen between 0.51°C and 1.20°C above normal.  And the trend is ever upwards.

This trend is reflected in many countries around the world with 2016 now also recorded as the world’s hottest year on record.

There are reasons for that record.  As NIWA says, for New Zealand, it is a combination of three factors.

nzweather-records2016One is that ocean temperatures around New Zealand were unusually warm throughout the early part of 2016.  Last year’s El Nino weather pattern was a key contributor to this.

Second was unusual atmospheric pressure patterns resulting in more northerly and nor-westerly winds that therefore, picked up heat from the warmed oceans.

Third was increased green house gases in the atmosphere that mark a long-term warming trend, aka global warming.  Over 90% of that additional heat in the atmosphere gets absorbed in to the oceans, which loops us back to reason number one.

Science has no real understanding of how much more heat the oceans can tolerate.  It is known that ice loss in the Arctic and Antarctic is causing sea level rise on top of that caused directly by the thermal expansion of our oceans.

There is another aspect to ocean warming not often spoken about.  Higher temperatures reduce the oxygen carrying capacity of water and also increases the biological oxygen demand of the micro-organisms in the water.    

So dissolved oxygen levels in our oceans are declining and with oxygen a key driver of marine ecosystems, much of our food chain is at risk.

This was recognised in a Ministry for the Environment report, “Changes to our oceans pose serious concerns“, published in October last year. Our government recognises the risks, but remedial action is not being taken.

At a global level, the response to climate change is to use “best endeavours” to keep average temperatures below 1.5°C of warming.  At the country’s average of 0.81°C we are more than half the way there.

The climate impacts on different parts of the country vary a lot.

For Pukekohe, the minimum mean temperature was up 0.9°C.  This will have implications on pest control in our horticultural areas – more pests will survive the winter cold and become a problem in the following growing season.

And the annual average temperature in Pukekohe was up 0.8°C.  This will have implications on water retention in the soil and on water consumption – more water will be required to assure us our economic future.

These are not the halcyon days of summer I remember from my youth.

Instead, there is an increasing sense of urgency for us to take actions to mitigate the prime cause of global warming – our release of new sources of carbon dioxide to the atmosphere.

Those actions must be on three prime fronts.

First is to cease harvesting trees.   Trees remove carbon from the atmosphere, leaving less to add to global warming.

Second is to stop putting new carbon in to the atmosphere.  Fundamentally, this means no more extraction of fossil fuels.  That’s unlikely in the short term so things we can do individually to make a difference, are to significantly cut back on car journeys and air travel.

Third is to remove carbon from the atmosphere and sequester it away in our soils.

For as long as economic imperatives define the climate actions we choose to take, the first two of these will be difficult to realise.  The third action, sequestering carbon in the soil, is an easy do, one that each and every one of us can do today, tomorrow, the next day and so on, until we make that essential difference.