6 Nov 2012

Freak Weather, Or Changing Climate?

By Steve O'Connor
Did global warming cause Hurricane Sandy? After the latest batch of weather disasters the scale of the climate problem is becoming clear - but the solutions are within our reach, writes Steve O'Connor
Most people have heard that old joke about a man climbing onto his roof duing a flood: he prays hard and refuses help several times, insisting that God will save him, but eventually drowns. In Heaven, the man confronts God, who angrily replies, "I sent you two boats and a helicopter, what more did you expect?"

After the devastation that yet another "freak" weather event wrought last week, the question must be asked: how many more "Sandys" have to occur before people start seeing greenhouse gas pollution as the main underlying cause?

There are glimmers that Americans, at least, might be finally not only getting the message about climate change, but are increasingly willing to link it to extreme weather. The mayor of New York, Michael Bloomberg last week made a surprise announcement backing Barack Obama, citing — among other things — his stance on climate change.

Scientifically speaking, we currently lack the knowledge to attribute individual events purely to climate change, yet we know that the weather is definitely getting weird.

National Geographic asked recently, "What's up with the weather?" concluding that it's probably a combination of human-made shifts in Earth's climate and a natural stretch of bad luck; Dr Michael MacCracken, Chief Scientist at The Climate Institute, told me a couple of months ago that meteorologists are starting to find their empirical "rules of thumb" aren't working as well as they used to.

Importantly, evidence is continuing to mount that a warmer Arctic affects the polar jet-stream in a profound way, leading to a wavier motion and increased formation of blocking patterns. Is it merely a coincidence that warmer sea-temperatures and an unusual meterological blocking ridge were both major factors in Sandy's scale, size and path? The link between extreme weather and climate is getting stronger and harder to deny.

So, what's up with the climate?

It's starting to become apparent that, paradoxically, we know both less and more about the climate: more ways that the climate can be influenced (by mechanisms such as the polar jet-stream, for example) but less about how these mechanisms actually work and interact with one another. Our state-of-the-art models are lagging painfully behind reality, and it's not just a question of adding more raw computing power — although that would help enormously.

Recently, there was a brief media blitz when the Arctic ice-cap reached a record low in its annual melt, but unless you're a climate junkie, the reported facts and figures probably don't mean all that much.

For anyone left in any doubt as to how bad the situation is, the diagram below shows how satellite measurements of the ice coverage (the thick red line) stack up against computer models from the last Intergovernmental Panel on Climate Change (IPCC) report.

As dramatic as this is, it still fails to fully capture the speed at which ice is disappearing. The total volume is now almost a fifth of what it was only 30 years ago, leading some, like Professor Wadhams of Cambridge University, to predict a seasonally ice-free Arctic in as little as four or five years. These conditions haven't occurred on Earth for perhaps millions of years — and in my opinion herald the emergence of a new, more dangerous phase of climate change.

Least understood are the so-called large-scale climate discontinuities. Some of these — such as the carbon cycle becoming unbalanced — are predicted to have a low probability of happening, yet have potential impacts that are so far out of the realm of everyday experience, to even mention them would be tantamount to scare-mongering. While it may not be a pleasant thought, we need to ask ourselves if our best models are capable of getting it so spectacularly wrong about the Arctic, can we afford to be confident about such predictions?

It's not as if we don't have solutions on hand: the technology that can take us to a decarbonised economy already exists, such as baseload solar thermal power stations, solar voltaic power and wind farms. One of the great things about renewable energy is that the more you use, the cheaper it gets (unlike fossil-fuels where the more you use, the more expensive they become). Just imagine how much would be possible if the multi-billion dollar subsidies each year to the fossil-fuel industry were instead invested in clean energy.

There are many obstacles in the way of this becoming reality, but an example of a real success story is to be found in Canberra: ACT Labor has shown tremendous courage by recently announcing the jaw-dropping target of 90 per cent renewables within just eight years, making the territory a world leader. Partnership with the Greens (who still hold the balance of power) and concerted effort from community groups such as "Canberra loves 40%" were essential ingredients in creating such ambitious goals.

As much as some would like it to go away, the sad reality is that climate change will probably get worse over the next few decades no matter what we do. The psychological toll this will take on all of us cannot be overestimated, yet this could easily become an excuse to prevaricate. Or worse.

Future generations will no doubt look back and ask what was the moment we finally made the decision to do something about climate change. I hope that moment is now.

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This user is a New Matilda supporter. David_H
Posted Tuesday, November 6, 2012 - 19:41

The irony of ACT Labor's position regarding renewables is that Canberra is utterly captive to private motor vehicle transport not only as a means of mass transportation but also for the supply of almost all goods coming into the city. The goals also need to be viewed in the context of a previous ACT government aspiration to reduce waste going to landfill by 100%, which has passed it's useby date of 2010 rather ingloriously.

Not that these objectives aren't worthy, just that its easier sometimes for politicians to make grandiose statements while much harder to actually delivering the intended result. Genuine progress here might depend less on grandstanding and more on coming to grips with why these ideas are so hard to implement.

Warwick Rowell
Posted Wednesday, November 7, 2012 - 11:44

Warwick Rowell

Good article Steve

Weather events like Sandy are proving that dynamic systems are still very hard to predict, and very dynamic ones even more so! The 1991 "Perfect Storm" was another even rougher example that occurred close to this one.

We have experienced two such storms here (Dunsborough, Western Australia): one last June and one in 1997, with wind speeds over 170 kph.

For analysis coming the other way, so to speak, refer to http://www.columbia.edu/~jeh1/mailings/2012/20120803_DicePopSci.pdf

Here James Hansen lays out the data in support of his dice metaphor: If 1950-1980 weather data is plotted onto a die (one die, two dice , one mouse, two mice - don't you love English?) so two white sides are "normal", two blue sides are "cooler", and two red sides are "warmer", then present data show the (updated to 2012) die has (approximately) 1/2 a side blue, two white, three red, and 1/2 dark brown: which colour represents weather events far beyond three standard deviations from the mean.

BTW James makes a good case for the 1950-1980 climate average as being the end of the Holocene era - the period when mankind benefited from the most stable climate in paleohistory.

Or another way he analyses things: Extreme heat events used to occur on 0.5% of the US continental land mass each summer, now it is 10%.

The difficulties we face in dealing with climate change and other issues will test our "civilization"to the limit, and our grandchildren will have to bear most of the brunt of our reluctance to change.

For some ideas on what might help, check out warwick.rowell.com.

tigger99
Posted Thursday, November 8, 2012 - 13:50

Freak weather, or changing climate? Well, neither actually.

From August 1954 through August 1955, the East Coast of the US saw three different storms make landfall—Carol, Hazel and Diane—that in 2012 each would have caused much more damage as Sandy.

If you look at the frequency of all storms, the US is currently in an extended and intense hurricane ‘drought’. The last Category 3 or stronger storm to make landfall was Wilma in 2005. The more than seven years since then is the longest such span in over a century.

If you contend that man-made global warming is changing the climate, the frequency of storms would suggest it is in fact a calming effect!

Also, throwing in a random graph on the thinning of the arctic ice sheet is spurious at best. I could throw in a graph that shows how the Antarctic is colder and has the largest ice sheet on record. If it’s global warming, why is Antarctica colder?

Also the arctic graph shows data to September. Guess what, latest data for October shows a record freezing. Yep, it’s getting colder up north (because winter is coming) and the ice is back. In other words a completely typical sea ice seasonal variation.

This is a disappointing article.

thomasee73
Posted Saturday, November 10, 2012 - 00:30

Thanks for your publication, Professor tigger.

zeroxcliche
Posted Sunday, November 11, 2012 - 01:05

I say this every few climate articles - the 11 year solar irradiance cycle is coming out of a trough and heading toward a peak in 2020 - thats about .2 C worth - add this to anthropogenic forcing and this decade is going to reveal climate change directly to us. What then.... the status quo will get better at looking like it is doing something, people will tell themselves its being taken care of - will Canberra get out of its cars or go electric, will we stop exporting coal - sorry to say I nolonger believe the public has the will or moral capacity for whats in front of us.

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