The last couple of yarns were sort of cliffhangers, and even the ones about lambing were never really resolved. Like so much in life, these stories are not really finished, but at least here’s an update.
In the first episode of this climate change series, we met the stars of our drama: the greenhouse gases carbon dioxide, methane and others. We know the levels of these gases are increasing in the atmosphere because of the pioneering work of Charles Keeling, whose observations atop Mauna Loa on the big island of Hawai’i showed a steady increase in CO2 from the early 1950s to the present.
How do we know the source of Keeling’s extra CO2 is in fact human activity in the industrial era and not simply natural variability in atmospheric CO2?
Carbon dioxide, like chocolate, is a good thing in moderation. Without carbon dioxide gas in our atmosphere, life as we know it could not exist. This is because carbon dioxide molecules are nature’s own tiny solar panels—absorbing, retaining and re-emiting heat from the sun.
However, as the concentration of carbon dioxide increases, the atmosphere is able to retain more and more heat, with consequences for life on our planet.
Over the past 32 years, the Maurice White Trust has transformed large swathes of its 1500 hectare (3700 acres) Hinewai Reserve from steep, gorse-infested ex-farmland back to its pre-settlement native forest ecosystems on Banks Peninsula south of Christchurch, New Zealand. The work began as an unlikely partnership between botanist and artist Hugh Wilson, who developed a passion for the plants and wildlife of his childhood home, and Maurice White, a local businessman with a passion for native birds. Together they established Hinewai as an experiment in botanical succession as a means to eliminate gorse and re-establish native forest ecosystems in catchments that run from the hilltops above Akaroa down to the sea. Their story is told in a wonderful video recently released: Fools and Dreamers.
On the steep hillside near the western boundary of my property, and visible from the highway as you travel south from Oatlands, is a village of small plastic domes. When they first went up, I used to think they looked like extra-terrestrial vehicles just the right size for a baby Yoda. In fact, they are part of an international research program looking at the effects of climate change on native pastures in many locations around the world. The Tasmanian component of the program is run by Prof Mark Hovenden and his team from the University of Tasmania.
The Indian Ocean Dipole is at a record high value. To quote Dr Suess’s Sleep Book: “This may not seem very important, I know. But it is, so I’m bothering telling you so.” The IOD is an indicator of the distribution of surface temperature in the Indian Ocean. When it’s positive, like now, warm water is pushed up against Africa, and cooler water is found near Australia. This is like a smaller version of El Nino, where warm water is squished up against South America and cooler surface waters are found near Australia.
