New book on Australia’s climate history shows need for urgent action

In Australia, eight of the 10 warmest years on record have occurred since 1998.

Sunburnt Country: The History & Future of Climate Change in Australia
By Joelle Gergis
Melbourne University Press, 2018

This is a very readable book written by a climatologist, an expert on the weather in the Southern Hemisphere from the University of Melbourne, writes Coral Wynter.

The book starts with the arrival of the First Fleet and their experiences with the wild weather they encountered at Port Jackson. The convicts and soldiers almost starved to death, totally ignorant of the land and its plants. The local Aboriginal people, on the other hand, thrived on fish, kangaroos and local greens.

The colony found itself forces to eat rats, dogs and crows to supplement their meagre diet. By 1790, it was on the verge of collapse as the Europeans were left cold, wet and hungry after the loss of the ship, Sirius, which was attempting to bring supplies from Norfolk Island.

In February 1791, the temperature rose to 38.6°C and reports refer to birds and bats falling out of the sky. There was a drought in 1792-93, but a good rain came with La Nina weather pattern in 1795, which opened up land around Parramatta. There was another drought in 1799, followed by the first recorded bush fires in Sydney that December.

Gergis explains the main aspects of Australia’s climate, the El Nino-Southern Oscillation (ENSO), which causes our climatic bipolar disorder. This causes alternating huge droughts followed by devastating floods. ENSO does not have a reliable pattern, with events changing every three-to-seven years.

Our climate, and in particular rainfall, is affected by what is occurring in the Indian Ocean, called the Indian Ocean Dipole. There is another interplay between the low pressure of the South Pole, and the high pressure of the mid-latitudes, which determines the north-south movement of the westerly winds, referred to as the Southern Annular Mode. This is an important driver of rainfall across southern Australia.

The first non-Aboriginal weatherperson was Lieutenant William Dawes, whose original notebooks were rediscovered in 1972 in the library of the Royal Society of London. Dawes took meticulous measurements of temperature, pressure and winds. He often took readings up to six times a day from September 1788 until he left Sydney in December 1791. We have only learnt about Dawes from Kate Greville’s novel, The Lieutenant, published in 2010.

Dawes was a compassionate man who began to learn the local Eora Aboriginal language from a young girl, Patyegarang. Dawes was expelled from the colony for refusing to carry out a punishment raid against the local Aboriginal people on the orders of Governor Arthur Phillip.

Details of the climate from 40,000 years ago as told by the continent’s original inhabitants are recounted in the book. It details stories from the previous Ice Age about 20,000 years ago.

Gergis also did field work, using thin, wooden cores of the New Zealand primitive kauri pine to gain information about the past 2000 years. X-ray technology was used to measure distinct bands in the coral cores of the Great Barrier Reef. A measure of the annual river flow and seawater salinity in the coral can be obtained through luminescence, leading to a compilation of floods and droughts going back to 1648.

A picture emerges of Australia oscillating between extremes over the past 60,000 years. The picture reveals long droughts followed by huge floods, similar to that experienced since colonisation.

However, all this has gotten much worse since 1950. It is not widely appreciated that more than 90% of the total heat accumulated in the climate system since 1970 and about 25% of the total carbon dioxide, has been soaked up by the world’s oceans. The greatest warming has taken place close to the surface of the seas.

This has meant the ocean has acidified and shell-forming animals, including corals, oysters, shrimp, lobster and even some fish species, are most affected. Ocean acidification has increased by 30% since the start of the industrial age 250 years ago.

Ice cores from Antarctica can give us a reconstruction of the climate for nearly the past 800,000 years. Examination of air bubbles trapped in the ice core layers can give us a calculation of carbon dioxide and other greenhouses gases such as methane.

Data from the Law Dome in the Antarctic over the past two millennia have shown a dramatic rise in carbon dioxide concentration since the 19th century. Starting about 280 parts per million, the CO2 levels are now over 409ppm in May 2017.

If emissions continue unchecked, it would add up to 550ppm, including greenhouse gases such as methane and nitrous oxide, causing global temperatures to rise by 2°C by 2038. Such a warming would cause the disappearance of all the world’s coral reef ecosystems.

There is no doubt all the data and evidence from many different sources, such as trees, coral reefs and ice cores, points to a huge change in the world’s climate since the advent of the industrial age, caused by human activity.

A 2017 study estimated that by 2100, temperatures could become a staggering 7C higher. In Australia, eight of the 10 warmest years on record have occurred since 1998, with our hottest year being 2013, which was 1.2°C about the 1961-90 average.

During the 2012-13 heatwave, Alice Springs sweltered through 17 consecutive days of 40°C or more, even though it wasn’t an El Nino year. Above 40°C, people are at risk of heat stroke, and together with high humidity, these conditions can cause brain damage, organ failure, seizures and coma. With such a climate, Alice Springs and much of outback Australia will become unliveable.

We will see towns in the arid zone abandoned by mid-21st century. In Melbourne, the average intensity of heatwaves is 1.5°C hotter and occurs 17 days earlier than they did in 1980. The worst prediction is that Darwin’s average of 11 days above 35°C may increase to 265 days each year. By 2090, Brisbane, will have its number of days above 35°C rise from 12 to 55 days, making the heat and humidity of the summer excruciating.

About 54% of the world’s population lives in urban areas, with 90% of Australians living in cities. About 85% of Australians live on the coastal zone. By 2006, it was estimated that 1.5 million properties were located within 3km of the Australian coast and less than five metres above sea level. About 39,000 properties were within 110 metres of soft erodible shorelines.

This is cause for deep concern. And there is much more crucial information in the book than a review can convey.

Sunburnt Country is well written, with many personable accounts of how its information was collected. The vilification of Gergis by climate deniers is eye-opening, as they seek to suppress the facts.

The book contains reams of information as to how exactly Australia will be affected by climate change. We need to inform ourselves so that we can collectively struggle harder to prevent the scenario of this intergenerational crime against humanity.