The Royal Society of Victoria – Official Position on Climate Change

This position paper has been developed through the Royal Society of Victoria’s Policy and Advocacy Committee. The paper was circulated for review and consideration by the Society’s membership in December 2018, revised with feedback received and adopted as the Society’s Official Position by the Society’s governing Council in February 2019. This paper supersedes earlier positions on this matter.

The official position of the Royal Society of Victoria is that, given the irrefutable scientific evidence for human activity driving climate change, it is vital that policies that curb greenhouse gas emissions from all sources be developed and implemented as a matter of urgency on a global basis. For Australia, this would mean the encouragement of the development of renewable sources of power, such as solar and wind generation with appropriate methods of storage, the improvement of energy efficiency, and to encourage the consumers of Australian coal (mostly Japan, Korea, India and China) to adopt similar policies.

mean temperature anomalies BoMGlobal climate change and global warming are real and observable. It is well recognised that there have been fluctuations in global climate on the millennial time scale, but what has happened over the past 200 years is very different. The global mean surface temperature of the Earth increased by around 0.9°C from 1880 to 2012. The first decade of the 21st century was warmer than any other decade since at least 1850 (when global temperature measurements first became available). The rate of warming has been largest in the latter part of the 20th century. Global surface temperatures increased by about 0.7°C from 1951–2012. Since the 1980s every decade has been warmer than any other decade since 1850, and each successive decade has been warmer than the previous one. Moreover, 2016, 2015, 2017, 2014, 2010, and 2005, in that order, were the six warmest years on record.

annual mean temperature anomalies BoM
Annual mean temperature anomalies for Australia, 1910 – 2012. Source: Bureau of Meteorology

Australia’s climate is changing. Since the introduction of robust, instrumental surface temperature measurements in the early 20th century the mean surface temperature of Australia has increased by about 0.9°C. This is similar to the global average increase. Warming is slightly stronger in night-time minimum temperatures than in daytime maximum temperatures. This warming has been concentrated in the post-1950 period with little trend prior to 1950. Mean temperatures have increased in all parts of Australia, with the strongest warming trends in the central and eastern interior of Australia and the weakest in parts of northern Western Australia and some parts of New South Wales. The year 2013 was Australia’s hottest year on record, with 2014 ranking third, and 2016 ranking fourth. During the instrumental record (since 1910), Australia’s four hottest years, and nine of the ten hottest, have occurred since 2002.

The composition of gases in our atmosphere is crucial to maintaining a warm planet and life on Earth and even small changes to this composition can have a big effect on our climate. Water vapour, carbon dioxide and other gases that are present in small amounts (often collectively called greenhouse gases) increase the capacity of the atmosphere to absorb and emit infrared radiation. The mean surface temperature increases as the atmospheric concentration of greenhouse gases increases because the atmosphere emits more infrared radiation (both upwards and downwards), some of which is absorbed by the Earth’s surface. It is for this reason that the mean surface temperature is higher than it would be otherwise, without an atmosphere or greenhouse gases. This process, called the natural greenhouse effect, keeps the surface of the Earth and the lower atmosphere warm enough to sustain the mean global surface temperature of about 15°C.

Proportions of atmospheric greenhouse gases BoM
Proportions of greenhouse gases in the atmosphere, 1975-2015. Source: Bureau of Meteorology

It is now certain that the human activities that have increased the concentration of greenhouse gases in the atmosphere contribute significantly to observed warming. Further, it is extremely likely that these human activities are responsible for most of the observed global warming since 1950. The warming that is associated with increases in greenhouse gases originating from human activity is called the enhanced greenhouse effect. The atmospheric concentration of carbon dioxide has increased by around 40% since the start of the industrial age, and has been measured as higher now than at any time in at least the past 800,000 years. In 2015 the amount of carbon dioxide in the atmosphere exceeded 400 ppm, which is a level likely last seen 2–4 million years ago. The increase in carbon dioxide is a direct result of burning fossil fuels, broad-scale deforestation and other human activity. Concentrations of a range of other potent greenhouse gases, such as Chloroflourocarbons (CFCs), methane and nitrous oxide, have also increased as a result of human activity, and have contributed to the observed warming. Some other by-products of human activity, most notably industrial aerosols, have had a cooling effect on the atmosphere, and have offset some of the warming from the enhanced greenhouse effect.

Why are we confident that the warming is due to human activity rather than natural climate variability? First, the observed warming in recent decades is consistent with the fundamental theories of the physics of the atmosphere and its behaviour. Second, estimates of past climates suggest that the mean surface temperature of the Northern Hemisphere in the late 20th and early 21st centuries exceeds the temperature at any time during at least the last 1,400 years. Third, climate models (computer simulations of the Earth’s climate) correctly simulate the temperature record of the 20th century (including some periods of relative cooling) when both natural factors (internal climate variability, volcanic emissions) and human influences (increased greenhouse gases and aerosols, and decreased stratospheric ozone) are included, but not if human influences are omitted.

Our climate is very likely to continue to change as a result of human activity. Global temperature increases are already set to continue until at least the middle of this century, even if emissions of greenhouse gases were reduced to zero. The magnitude of warming and related changes can be limited by controlling the total amount of carbon dioxide and other greenhouse gases emitted into the atmosphere as a result of human activities; future climate scenarios depend critically on future changes in emissions. Future global mean temperatures over the period 2016–2035 are likely to be 0.3°C to 0.7°C higher than temperatures in the period 1986–2005. By the end of the 21st century, with a rapid transition away from fossil fuels, climate models suggest warming ranging from 0.3–1.7°C and sea-level rise ranging from approximately 0.3–0.6 m. With ongoing intensive use of fossil fuels the projected ranges of warming and sea-level rise are approximately 2.6–4.8°C and 0.5–0.9 m, respectively. In the short-term (out to 2030), most of the uncertainty in these projections is due to the uncertainty in the way climate models represent physical processes. Later in the century, the economic and population growth and the future level of greenhouse gas emissions and anthropogenic aerosols become the dominant uncertainties.

Australian Annual Surface Temperature Anomolies
Australian Annual Surface Temperature Anomaly. Source: Bureau of Meteorology

The mean Australian surface temperature is likely to increase by between 0.6 and 1.3°C by 2030 when compared to the period 1986–2005. This range of warming for 2030 is similar for all emissions scenarios. However, the rate and amount of carbon dioxide produced into the future becomes more influential by 2090. Continued intensive emissions, a so-called high emissions scenario, is likely to produce an increase in Australian average temperatures of 2.8°C –5.1°C by 2090. A rapid reduction in the amount of carbon dioxide emitted is critical to control temperature increases that are limited to between 0.6°C and 1.7°C.

Climate models suggest that the warming in inland Australia will be larger than in coastal areas, with the least warming (on an annual mean basis) expected in southern Australia. There are also seasonal differences in warming, with the greatest warming likely to occur in the spring.

There is very high confidence that Australian sea levels will continue to rise during the 21st century and that the oceans surrounding Australia will become more acidic, affecting marine ecosystems, especially the Great Barrier Reef.

We should note that our energy consumption is approximately 1.5% of the global production, but that we are the largest exporter of both coal and natural gas. We therefore have some leverage on global consumption, and should diplomatically use this to influence our customers to adopt similar policies.

2070 Projections
2070 Projections. Source: Dept of Climate Change & Energy Efficiency, CSIRO, Bureau of Meteorology

The official position of the Royal Society of Victoria is that, given the irrefutable scientific evidence for human activity driving climate change, it is vital that policies that curb greenhouse gas emissions from all sources be developed and implemented as a matter of urgency on a global basis. For Australia, this would mean the encouragement of the development of renewable sources of power, such as solar and wind generation with appropriate methods of storage, the improvement of energy efficiency, and to encourage the consumers of Australian coal (mostly Japan, Korea, India and China) to adopt similar policies.

For further information see:

The AMOS Climate Change Statement, Feb. 2016.

Climate Change in Australia: http://www.climatechangeinaustralia.gov.au

Intergovernmental Panel on Climate Change – 5th Assessment Report: http://www.ipcc.ch

IPCC Special Report on global warming of 1.5C: http://www.ipcc.ch/report/sr15/ .

Australian Academy of Science – The Science of Climate Change, Questions & Answers. https://www.science.org.au/learning/general-audience/science-booklets-0/science-climate-change