Taking the heat out of global warming

Last year was Australia’s warmest year on record and the second warmest year globally.

Global warming is fact. Temperatures are rising. Since 1910, our planet has warmed by around 0.8C. Since 1998, we have experienced the five warmest years on record globally. The past 30 years have seen acceleration in the rate of warming to almost 0.2C per decade.

In Australia, we are now experiencing more hot days and fewer frosts and very cold days.

The Europe heatwave of August 2003 claimed at least 35,000 lives. The damage caused by floods and storms is increasing. During the 1950s, the world experienced 13 extreme weather-related catastrophes. The past decade has seen 49 such events.

Sea-ice and glaciers are retreating. Floating sea ice in the Arctic is diminishing rapidly, with predictions that all ice will disappear in summers by the end of this century. This has not happened for at least a million years! A survey of 88 glaciers revealed that at least 79 were receding, while only four are growing. The melt rate of the massive Greenland ice sheet is twice what it was a decade ago, as Antarctic ice shelves disintegrate.

A recent Australian research expedition to the Southern Ocean found profound changes to the temperature and salt-levels of deep-ocean water from the situation 10 years earlier. Melting Antarctic glaciers are probably the cause of the change, which could affect oceanic circulation patterns. The oceans transport vast amounts of heat around the world, so changes like these could have a major impact on climate.

Numerous species of plants and animals have moved towards the poles, or to higher altitudes to escape the heat. There are increasing events of coral bleaching. Sea levels are rising, at a rate that has increased during the past ten years. Natural changes marking the beginning of spring are occurring two days earlier each decade. Oceans are becoming warmer and fresher as well as more acidic due to higher levels of carbon dioxide.

What is causing climate to change? The answer, in large part, is us. Most of the global warming of the past 50 years is due to human activities. By pumping billions of tonnes of carbon dioxide and other heat-trapping gases into the air we are raising the temperature of the atmosphere.

Atmosphere concentrations of carbon dioxide, the key greenhouse gas we release into the air, are more than a third higher than they were before industrialisation.

By the year 2030, Australian annual average temperatures are likely to be 0.4 to 2C greater than they were in 1990. Water resources in Queensland are likely to be further stressed due to projected growth in demand and climate-driven changes in supply for irrigation, cities, industry and environmental flows.

CSIRO recently released a report describing how rising temperatures may affect Australian ecosystems. Should conditions become 1-2C hotter, considerable areas of the Great Barrier Reef would be bleached every year. Ninety per cent of the core habitat for animals in the northern Australia tropics would disappear.

Industry is accustomed to dealing with risk and uncertainty. Business leaders know that the best approach is to gather as much information as possible before making decisions, and to act within risk management frameworks. Climate change is an issue that no one should ignore.