Climate Change in the Bay of Islands.
Much of the time people think that climate change is for poor people in faraway lands but, in reality, it is a planet wide phenomenon that we will all feel in the course our lifetime. Threats from a changing climate are very wide ranging and have different timescales so that one of the most serious, ocean acidity, is slow, relentless and devastating and largely out of sight.
So what can we expect to see in the Bay of Islands? The most immediate and obvious is probably rising temperatures and various consequences. The world temperature has already risen about 1 C, which we hardly notice in the Bay region, but the planet is very sensitive and it has increased the differential in temperature between the Antarctic and the tropics and this has caused the westerly winds in the Southern Ocean to increase in speed and power. This has resulted in us getting more westerly winds. which for the Bay region are drier and a decrease in easterlies which bring us rain. The result is that, with higher temperatures and less rain we will have to deal with more drought.
One of the great tragedies of the heat and drought combination is the loss of our trees, who are very sensitive to their environment and do not take changes to temperature and moisture the way that people and animals can.
Counterintuitively we can expect more floods because the atmosphere can hold 7% more moisture for every 1 C increase in temperature. Rain bearing systems draw in moisture from hundreds of kilometres of ocean and concentrate it into a rainstorm that can escalate very quickly as the temperature rises. We have experienced two rain events of more than 350 mm a day and in 2015 we had three 200 mm rainstorms in a month so it is already happening. There is also a strong likelihood of more tropical storms coming down from the North as the major atmospheric circulation patterns in the Hadley cell expand southwards.
Because the Bay region is hilly the floods clear quickly, but these events cause huge damage to the environment by carrying away our topsoil and dumping it in the Bay. Topsoil cannot be replaced and we are losing 6 tonnes per hectare a year on average and these big storms make it worse. One big event put 25 mm of mud over the Bay sea floor, smothering our fish breeding grounds.
Classic solutions of widening and deepening rivers only speeds up the river water and gives it more destructive power.
Because the Bay region is hilly the floods clear quickly, but these events cause huge damage to the environment by carrying away our topsoil and dumping it in the Bay. Topsoil cannot be replaced and we are losing 6 tonnes per hectare a year on average and these big storms make it worse. One big event put 25 mm of mud over the Bay sea floor, smothering our fish breeding grounds.
Classic solutions of widening and deepening rivers only speeds up the river water and gives it more destructive power.
Sea level rise will bring classic problems to infrastructure with the coast road between Paihia and Opua being an early casualty plus houses on the water front throughout the Bay. The IPCC forecast of 900 mm by the end of the century is likely to be upgraded substantial as new research into melting ice caps is confirmed. One of the consequences of sea level rise over one metre is the mass movement of displaced people and here we can expect thousands of refugees from around the Pacific looking for a safe place to live.
We live on a water planet and get much of our protein from the sea. Ocean acidity will have a devastating effect on calcium carbonate structures of plankton, the base of the food chain, and mussels, clams, crayfish and many other maritime creatures. This will be a tragedy of immense proportions.
Overall, it’s not good news which is why I have joined Living Waters and spend my time planting trees on the riverbank to strengthen the resilience of our rivers and streams.