FAQ

Greenhouse gases are generally defined as the six gases carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulphur hexafluoride. Human activity has a direct impact on the levels of greenhouse gases in the atmosphere.

Weather relates to the atmospheric conditions prevailing at a particular place and time. Climate is the average weather over a period of time for a region. Climate depends, amongst other things, on an intricate set of interactions between solar input, topography, continental distribution, greenhouse gases in the atmosphere and ocean-atmosphere interchanges of heat.

Climate change is a change in the statistical distribution of weather over a period of time. It can be a change in the average weather or a change in the distribution of weather events around an average (for example, greater or fewer extreme weather events).

In the current context climate change refers to changes in modern climate driven by global warming.

Yes, Australia is already a hot continent (Africa is the hottest) and it is the driest inhabited continent (Antarctica is the driest continent). Furthermore, Australia grows most of its irrigated food crops in the Murray-Darling Basin, where it is predicted that climate change will reduce river flows by more than 40 per cent.

The earth's surface is warmed by radiation from the sun that passes through our atmosphere. As the surface warms it re-radiates that energy as infra-red energy, which is a longer wavelength than the incoming radiation. Greenhouse gases in the atmosphere, such as carbon dioxide, then capture that outgoing, long-wavelength radiation and re-radiate it back to the surface. This raises the temperature of the surface above what it would be without the greenhouse gases. The overall effect is that the surface temperature is about 32 degrees Celsius warmer than it would otherwise be, which makes the planet habitable for us. The problem is that human use of fossils fuels is greatly and very rapidly increasing the amount of carbon dioxide in the atmosphere and so raising the surface temperature even more, leading to rapid climate change.

Global warming is usually taken to mean the rapid and ongoing increase in the average near-surface air and ocean temperature of the Earth since the early 20th century. The Intergovernmental Panel on Climate Change (IPCC) has concluded that most of the observed temperature increase since the early 20th century has been caused by increasing concentrations of greenhouse gases resulting from human activity such as fossil-fuel burning and deforestation.

Increasing global temperature will cause species extinctions, changes in agricultural yields, and increases in the intensity of extreme weather events. The warming will be strongest at the poles and so we will see glaciers, permafrost and sea ice continuing to retreat. It will also cause sea levels to rise and will change the amount and geographic distribution of precipitation (probably including expansion of subtropical deserts),

Human activity since the industrialised age has caused rising levels of greenhouse gases. Mankind has benefitted from a cheap and plentiful supply of fossil-fuel. Carbon emissions are a by-product of fossil-fuel. While we enjoyed the cheap energy, the balance of gases in the atmosphere changed. What mankind thought a good thing was not such a good thing!

Scientists have measured greenhouse gases in the atmosphere through time. The combined level of greenhouse gases in the atmosphere is measured as CO₂e ppm (parts per million). CO₂e is the symbol used to represent carbon dioxide equivalents and generally includes the six main greenhouse gases, carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons and sulphur hexafluoride. Before the industrial era (that is, only 200 years ago) the atmospheric concentration of carbon dioxide was about 280 ppm (0.0280 per cent). Today the global level of CO₂e is 455 ppm, of which 386 ppm is CO₂ (carbon dioxide). This is a stunning increase in a very short time. The problem is that the greenhouse gases make up only a tiny percentage of the atmosphere and so the 29 Gigatonnes of carbon dioxide that we emit every year can make a significant impact. While this may sound small at 0.0386 per cent of the atmosphere, it is the next major gas after nitrogen and oxygen which make up 99 per cent of the atmosphere. The problem really starts to come to life when you consider that over the last 650,000 years CO₂ levels ranged between 190 and 280 ppm. That is up until about 200 years ago when the proportion of CO₂ started to rise at an increasing rate.

The weight of evidence supporting human induced damaging climate change is overwhelming. The vast majority of scientists around the world are convinced of the impact of human involvement. For many years the Nobel Peace Prize winning Intergovernmental Panel on Climate Change (IPCC), the largest group of international scientists assembled for one cause, has raised its concerns on climate change. Around the world governments have commissioned research and released reports indicating the gravity of the situation and the urgency for action (see links). Climate change is a global issue. Every country will be affected. Every living thing will be touched.

The consequences of our current levels of carbon emissions are unacceptable. We have to recognise that the future depends on choices we make today and so we have to change our behaviour now to fix the problem. We need to be emissions aware and make deep cuts in carbon emissions. We need to be Climakind.

Research on climate change:

The Australian Government – Effects of Climate Change

http://www.aph.gov.au/library/Pubs/ClimateChange/effects/effects.htm

UK Climate Projections

http://www.defra.gov.uk/environment/climate/documents/uk-climate-projections.pdf

Global climate change impacts in the United States :

http://www.globalchange.gov/publications/reports/scientific-assessments/us-impacts/download-the-report

IPCC – The fourth Assessment Report (AR4)

http://www.ipcc.ch/

Studies conducted around the world conclude that acting now to help stop damaging climate change will cost less than if we wait until later. The UK government assessment conducted by Sir Nicholas Stern noted that the cost of adapting to climate change could be twenty times the cost of reducing emissions to avoid the worst impacts. The Garnaut Final Report in Australia indicated that ‘”the costs of well-designed mitigation, substantial as they are, would not end economic growth in Australia, its developing country neighbours or the global economy; unmitigated climate change probably would.” Acting now not only reduces the overall costs of managing climate change but potentially brings an increase in the number of jobs in climate change related industries. Furthermore, if we do nothing now, we will miss the window of opportunity to stop damaging climate change.

Decisions we make today determine the emissions we are responsible for in the future. Building emissions-intensive fossil-fuel infrastructure increases the emissions released into the atmosphere for a long time. The carbon dioxide we emit today could be in the atmosphere for 200 years. Infrastructure, such as power stations and buildings cost enormous amounts of money, and once built can be difficult and expensive to alter or replace. Plans for infrastructure investments should take into consideration viable low-carbon technology with urgency.

This urgency is not new - the basic science underpinning our understanding of global warming has been known since the landmark work of Svante Arrhenius in 1896. The IPCC publicly recorded their concerns suggesting the human influence on global warming in 1995, after years of research and review. The message was largely ignored, even ridiculed. In later reports they noted that if we left it until 2005 to reduce emissions then our window of opportunity and number of alternatives narrowed significantly as to what we could do to stop damaging climate change. Most of the world missed that message. Our choices are now fewer. We must choose effective tools to make deep cuts in emissions in order to help stop damaging climate change.

The IPCC is a scientific intergovernmental body set up by the World Meteorological Organization and the United Nations Environment Programme. It was established in 1988 to provide decision-makers and other interested parties with an objective source of information about climate change. The IPCC's role is to comprehensively, objectively, openly and transparently assess the latest scientific, technical and socioeconomic literature relevant to understanding the risk of human-induced climate change. The information IPCC provides in its reports is based on scientific evidence and reflects the viewpoints within the scientific community (all regions of the world and relevant disciplines). Their reports undergo a two-stage review - a first peer-review by experts and a second by experts and governments. In 2007 the IPCC was awarded the Nobel Peace Prize for its 'efforts to build up and disseminate greater knowledge about man-made climate change, and to lay the foundations for the measures that are needed to counteract such change. – quoted from page 1-3 of the Carbon Pollution Reduction Scheme

Despite the overwhelming evidence, some people distinguish themselves by disputing the whole concept of global warming and climate change. They are most often referred to as sceptics but many of them are better labelled as "professional disbelievers". For some interesting comments on this matter, have a look at the following links.

ScienceBlogs - “how to talk to a climate sceptic”

See Climate institute – Climate Myth Busters

The Australian govt – Uncertainty and Scepticism