Is climate change real and is it caused by human activity?
The world has been cooling since 1998
Temperatures have been going up and down slightly, but the clear trend is upwards. Since regular temperature records began in 1850, 13 of the past 15 years have been the hottest on record. Air samples from bubbles trapped in ancient ice, and cross-checked with other samples, show temperatures are rising faster than at any time since modern humans appeared.
The world is getting warmer but we don’t know the real cause
The causes of global warming are not absolutely certain, but the overwhelming majority of researchers, working independently in different parts of the world and using different models, have been coming to the same conclusions for two decades. The Intergovernmental Panel on Climate Change has reached the conclusion that it is “very likely” that human activity is the main cause of climate change; that is, there is a certainty “greater than 90 per cent”. Few scientific theories approach that level of certainty.
Climate change is caused by solar activity
Changes in radiation from the sun affect Earth’s climate, as do oscillations in the Earth’s orbit. But since the 1970s, when temperatures increasingly rose beyond norms, both the sun’s energy output and the Earth’s orbit have been stable. In any case, changing patterns of solar activity are included in climate models.
There is no consensus among scientists
There is clear and growing consensus in the world scientific community, and in Australia, that human activity is the main driver of climate change, and that cutting greenhouse gas emissions is the only way of slowing it. This is now the view of all the world’s leading national science academies and institutes. This does not constitute a unanimous view, however, with a small minority of scientists in relevant fields believing it is too early to be sure.
Why believe long-term predictions when meteorologists cannot even say if it will rain next week?
Climatology takes a step back from day-to-day weather prediction and looks at longer-term patterns. Numerous independent studies have concluded that carbon dioxide and other heat-trapping gases put into the atmosphere by humans are the new variable causing climate change. Climate models have been repeatedly tested and shown to accurately simulate climate scenarios.
Human emissions are smaller than natural emissions, so cannot be blamed for climate change
Rotting vegetation releases far more greenhouse gases than does human activity, but those emissions are absorbed by an equal amount of growing vegetation and by the oceans. The new element in this closed system is the extra carbon humans are removing from underground coal, oil and gas reserves and putting into the atmosphere.
Scientists are worried about losing funding, so they toe the government line
There is no evidence that undertaking research on climate change leads to government funding being cut or boosted. In Australia, the system is relatively transparent, with public funding for climate-change work being assessed alongside all other research work, and grants made based on quality of research, not on conclusions. When research is funded by private industry, the process can be less transparent. Much university research does not receive any outside funding.
Climate sceptics are being silenced
Advocates of this claim are yet to come up with evidence. Many Australian scientific researchers on climate change have told the Herald that the views of “climate sceptics” are given more prominence in the media than their numbers and arguments merit.
Sydney Morning Herald