At the Marlborough Earth Day party, held at A & P showgrounds in April, a number of visitors were asked if there were aspects of climate change that they didn’t understand. Liam asked, “How does climate change affect me personally?”
The short answer is, “not much, yet”. While some parts of the world have experienced dramatic warming and weather extremes related to human-caused climate change, New Zealand has largely been spared. We are surrounded by oceans which tend to moderate temperatures on land, and the oceans around us have been warming only gradually. Perhaps the most apparent evidence of climate change that we see is warmer ocean temperatures, drawing us into the water more during summer holidays.
Aside from the planet’s poles, where warmer temperatures are abundantly apparent in melting glaciers and vanishing sea ice, the natural weather cycles in most temperate and tropical countries make rising temperature hard to see in people’s daily lives. Was the last hot day due to climate change or just a natural weather cycle? We’ve always had heat waves. What is different now?
Here we must rely on climate scientists to tease out the long term trends in our constantly changing weather. They’ve observed global temperatures, measured at carefully designed sites around the world, to be increasing. On average, the earth’s surface has warmed by about 1 degree Centigrade since 1950. One degree is not much and would be a challenge for any of us to detect in our lifetimes, but it is a lot when compared to previous temperature variations, from historic records and as determined from ice cores of ancient snowfall.
Another principal threat of climate change, an increasing frequency of extreme weather events, has been predicted by weather computer models and is only now beginning to emerge, in a statistical sense, from the historical record of destructive storms, prolonged droughts and intense heat waves. Here the long term trends are more difficult to discern due to the episodic nature of these events (coming perhaps every few years or decades) and our relatively short history of eyewitness accounts. Add to this the fact that climate model predictions suggest global warming won’t necessarily increase the number of storms, but will increase the intensity of the storms that come. How many destructive storms does it take for scientists to determine a reliable trend toward greater (or lesser) storm intensity? It is a tricky problem, which is why we are only now seeing trends of more extreme weather. Unfortunately, the computer models suggest that weather extremes will only become more common as the planet warms. We may not see it now, but we can expect to in years to come.
So, in considering Liam’s question, although we haven’t experienced much change yet, we can see that changes are coming and they are almost all detrimental to our economy and way of life, and to the natural environment. I’ve mentioned only a few here; warmer average temperature and increased storm, drought and heat wave intensity. Add to this sea level rise, the oceans becoming warmer and more acidic, and a host of other changes, some perhaps even as yet unseen. The onset of these environmental changes is expected to unleash a series of social and economic changes, which will add to the pain. A short list includes rising insurance premiums due to floods, wildfires and sea level rise, rising food costs prices as a result of crop failures due to drought and flood, homes and forests destroyed due to wildfires, and fisheries collapse due to warming seas and algal blooms. Perhaps the most frightening is the human migration that will follow when people’s homelands become too hot or dry to live in, or go underwater due to sea level rise. Where will these people go in our already crowded world?
This is why we need to act, as early as we can, to prevent more damage down the road and preserve this planet for generations to come. We can take pride in the fact that New Zealand is leading other nations in acting on climate change, by limiting greenhouse gas emissions with an emissions trading scheme and through programs to sequester atmospheric carbon dioxide in new forests. As a nation and as individuals, we can make a difference.
The posts are a collection of opinion articles written by CKM member Tom Powell for the Marlborough Express. Tom is a retired geologist who came to New Zealand in 2004 to work in the geothermal industry on the North Island, is a New Zealand citizen and now lives in Blenheim.