James Renwick: Real climate facts there, if wanted

A stable climate that allowed civilisation to flourish and cities like Auckland to be built near the water is under threat. Photo / Nick Reed

The opinion piece written by Dave Hill - "Let's get the facts on climate change", published in the Chronicle on Tuesday - is a classic of misdirection.

He begins by pointing out that the climate has always changed. Absolutely right, meaning that the climate is sensitive to changes in sunlight and to changes in greenhouse gases.

The fact that we know the climate has been through hot and cold spells should be a cause for concern, not complacency.

The last 10,000 years have been a period of remarkable climate stability, very little change in global temperatures and virtually no sea level rise.

This has allowed modern civilisation to flourish, and for major cities to be built near the unchanging sea shore. That period of stability is over, thanks to human emissions of greenhouse gases.

Next, the idea that very little has changed over the past 20-30 years. In that time, global surface temperatures have warmed about one third of a degree, and the globe is now running about 1.1°C above the pre-industrial temperature level.

In the past 30 years, the oceans have soaked up about 200 billion trillion joules of energy, roughly what modern global society would use in 500 years.

Sea levels have risen nearly 10cm, enough to increase the occurrence of coastal inundation by a factor of three. Heat waves, floods, and storm surges are on the increase worldwide - New Zealand's unprecedented hot summer in 2017-18 gave us the flavour.

Then he quotes Fred Singer, whose former roles have included denying links between smoking and lung cancer, industrial pollution and acid rain, and CFCs and the ozone hole. He is a doubter for hire, as documented in the excellent book Merchants of Doubt.

The reality is climate change is very real, is caused by human activity and is a huge threat to human societies everywhere.

I find it sad that someone who chairs a ratepayers' association would aim to confuse his ratepayers and to divert them from action on the most critical issue facing the country and the world.

He finishes with "Climate change, yes - but first get the facts right". I suggest he starts with the latest reports from the Intergovernmental Panel on Climate Change, or the summaries from virtually any science academy in the world. The facts are easily found, and should be known, discussed, and acted on as a matter of urgency.