The Canberra Times - Paul Malone
If you examine a graph of Australian sharemarket prices over the last 50 years you will notice a long upward trend broken by periods such as those from 1970 to 1978 and from 2007 to 2013 when overall prices were flat.
This is typical of any graph of a trend. The real world doesn't run smoothly.
Scientists know that data will not always sit comfortably on the line. If it does, they'd be inclined to suspect something was amiss.
Global warming deniers either do understand this or choose to mislead their followers.
Advertisement
For some years now they have claimed that global temperatures have "plateaued". They argue that the data does not support the theory of human-induced climate change.
Now retired Liberal senator Nick Minchin led the Australian deniers, saying back in March 2011: "I think what's occurred is that there was a warming period from about '75 to the year 2000. It was part of a natural cycle of warning that comes in 25, 30-year cycles. The world has basically stabilised in terms of temperature since about 2000. There are many, many scientists who actually think we could be entering a cooling phase and I for one think that is more than likely."
Such views have been promoted in many media outlets and been given undue prominence, particularly by News Ltd papers.
Unfortunately for the deniers, the latest report from US National Oceanic and Atmospheric Administration does not support their claims. Gathering data from 1500 weather stations and numerous buoys and ships around the world NOAA has found that July was the warmest month in its 136 years of temperature records.
Not only that. The first seven months of 2015 were the warmest such period on record – 0.85 degrees above the 20th century average; and the rate of warming over the first 15 years of this century has been as fast, or faster than that of the last half of the 20th century.
Australian scientists have found much the same as their American counterparts. The Climate Council reported last week that the 1990s were warmer than the 1980s and the 2000s were warmer than the 1990s. All three decades were hotter than any preceding decade since 1850.
The line may not be perfect, the gradient may not be as steep as some had predicted, but the trend is clear.
The evidence for climate change comes from a host of different scientific perspectives – from basic physics and chemistry, to the meteorology and climate change sciences themselves; marine and coral studies; Arctic and Antarctic research; geology and biology.
To accept the deniers' argument requires you to believe in a conspiracy of unbelievable dimensions. The starting point would be to get researchers from 195 countries on the Intergovernmental Panel on Climate Change to come to the same conclusion. (Anyone who's ever been on a committee knows how hard it is to get three people to agree on something.)
There's no doubt about the science – the burning of coal, oil and gas is driving dramatic changes in our climate.
The latest report from the Climate Council says climate change is increasing the frequency and severity of many extreme weather events, including heatwaves and extreme bushfire conditions. Hot days have doubled in the last 50 years, while heatwaves have become hotter, last longer and occur more often.
Over the last 30 years extreme fire weather has increased in the populous south-east region of Australia – southern NSW, Victoria, Tasmania and parts of South Australia. Extreme sea-level events have tripled at Sydney and Fremantle since the middle of the 20th century.
Further increases in extreme heat in Australia are likely, with more frequent and more intense hot days and longer and more severe heatwaves. Deaths from heatwaves are projected to double over the next 40 years in Australian cities.
And, the council says, while action is building worldwide, Australia is lagging behind.
The constraints to moving forward are no longer technological or economic. They are political, institutional and ideological.
Australia must cut its greenhouse gas emissions much more deeply and rapidly, the council says. The government's recent pledge to cut emissions by 26 to 28 per cent compared with 2005 levels, by 2030 is not good enough.
Two maps (7a and 7b page C13) in the council's report compare rainfall from 1997 to 2013 with the rainfall over the reference period 1900 to 2013 and deserve careful policy consideration.
They suggest that cool-season rainfall is likely to decline across the southern part of Australia with the winter decreases as much as 50 per cent for south-west Western Australia.
The researchers say that the direction and magnitude of rainfall change in other seasons in southern Australia, and across the rest of the continent in all seasons, are uncertain.
But a layperson might conclude that northern and central Australia is getting a lot more rain. What might governments make of that? Will the flooding of Lake Eyre become a regular event?
There are many other policy matters that must be considered.
The Climate Council points out that the quantity of fossil fuel reserves that can be burned must be reduced if we want a better than even chance of limiting the rise in global temperature to no more than 2 degrees.
"Under any set of assumptions, effectively tackling climate change requires that most of the world's fossil fuels be left in the ground, unburned," the council concludes.
Coal, Australia's second-largest export, is the fossil fuel with the greatest proportion that cannot be used. The council says 88 per cent of global reserves are unburnable.
For Australia under any set of assumptions, including the use of carbon capture and storage technology, more than 90 per cent of coal reserves cannot be burned.
Furthermore, the council says, meeting the 2 degrees policy target implies that it is highly unlikely that any of Australia's potential coal resources beyond the reserves already being exploited can ever be developed.
It's time governments and policymakers accepted and planned for this reality.
No comments:
Post a Comment