Webdiary - Founded and Inspired by Margo Kingston

Today, Tuesday, we move on to look at climate change impacts on Australia and New Zealand, after some words of wisdom from Ian Campbell on the Government’s view which again is not expected to be enlightened or enlightening – though I would love to be surprised!

• Kevin Hennessy from CSIRO and Blair Fitzharris from Otago Uni kick off: "current mitigation is unlikely to prevent climate change in Australia and New Zealand and that some impacts will be inevitable. ... Large areas of mainland Australia and eastern New Zealand are likely to become substantially drier, although western New Zealand is likely to become up to 40% wetter. The frequencies of major floods, fires, droughts, heat waves and storm surges are likely to rise. ... Water security problems are very likely to be exacerbated. Coastal settlements are likely to be highly vulnerable. ... new adaptation processes and strategies need to be developed to manage future risks. There are likely to be limits to adaptation so there will be residual risks."
• Mark Mills, from a UK investment management firm, looks at investing and capital markets attitudes to climate change: "impediments which include an all pervasive attitude of “short-termism”, myths about fiduciary duty at the asset owner level, inbuilt incentives which encourage short-term trading and non-alignment of interest between asset owners and investment managers. ... The ultimate test of commitment of the investment markets is the percentage of the world’s assets which are managed in a way which incorporate an understanding of the significance of Climate Change. This figure remains low and will continue to be low until the so-called link between sustainability issues such as Climate Change and investment performance is proven."
• Sean Lucy, an Australian equivalent, continues the theme, with specific reference to emissions trading: "The introduction of emissions trading schemes has significant implications for business, in that it imposes a cost on something (the emission of greenhouse gasses), which previously was free. ... Regulatory efforts within Australia have to date been largely driven by the States, with the Commonwealth Government refusing to ratify the Kyoto Protocol or introduce a domestic emissions trading scheme. As a result, Australia remains largely on the sidelines of the emerging global market for greenhouse gas emissions, however there is a growing sentiment this will change in the medium term."

More to come.

Ian Campbell, Minister for the Environment is perhaps an exemplary member of the Commonwealth Government. Deeply confused on his specialist subject, he covers the huge gaps in common sense in his government’s policies with spin and flannel (and boy can he flannel).

His speech to the conference was upbeat and full of praise for how Australia is leading the world in action on climate change. Apparently in Canberra it’s well-recognised that the Europeans and Brits are looking up to us for leadership on this. This is not surprising, since according to Sen Campbell, “we do control an enormous percentage of the global climate systems” - a trick I wasn’t aware we’d perfected, but at least we now know who to blame for the drought.

Another fun quote: “Building 7800 power stations is a very important and a very good thing” - because “we need rapid and sustainable economic growth” to try and meet and beat the Millennium Development Goals. Not stated, but reasonably clearly implicit is the view that if we can’t have rapid AND sustainable, rapid will do. But he does agree with the scientific consensus that we do need to cut GHG emissions by 50-60% at the same time – which leads us to the key confusion (and conflannel): “we know that we were right not to sign up on Kyoto because it doesn’t go far enough”. Funnily enough someone in this collection of 380 people a large proportion of which are employed by the Government did manage to ask the big question: “if Kyoto doesn’t go far enough, why can’t we sign up for it and work on the detail of its problems from the inside?” The (lengthy) answer, if you can call it an answer, amounted to a claim that in private meetings other governments who did sign up for Kyoto wish they hadn’t, and think the US and Australia did the right thing.

Onward to key confusion two: “I think that emissions trading will be part of the answer in the long term” - but the Commonwealth doesn’t think that we want one in Australia right now – this answer complicated by a weird attack on the states (other than Victoria) for wanting to work through market mechanisms rather than by public expenditure on lowering emissions. So now the states know how to work better with the Commonwealth – regulate and spend, and stop leaving things to the market.

Bill Bayfield from the NZ Environment Ministry, on the other hand, was pretty clear that working within Kyoto is a given for the Kiwi government, despite the fact that it hasn’t been as easy for them as they’d hoped. “Adopting Kyoto means the whole of government at the highest levels is engaged in this issue." NZ will be implementing a carbon tax from April 2007. The recent Policy Review has some interesting things to say about carbon taxes vs emissions trading.

At present, international emissions markets are immature, making trading difficult and prices variable and unpredictable. We view the carbon tax as a transitional path toward full or partial emissions trading, which may become a better option as world markets develop. A tax gives firms a greater level of certainty about the price of emissions in the interim.

Why not wait until after 2012 and go straight to emissions trading then?

If New Zealand does nothing while awaiting the development of international markets, our emissions will continue to rise as will the future cost of reducing them. A low-level carbon tax (offset by the reduction of other taxes) sends a signal about the price of emissions that will, at the margin, influence investments in energy generation and use. If we can begin to curb our growth in greenhouse gas emissions now, we will be better placed to make a smooth transition to more challenging commitments after 2012.

Kevin Hennessy from CSIRO and Blair Fitzharris from Otago Uni talked about how we will need to adapt to climate change even if we do succeed in getting emissions down. The climate models are getting better and have a high degree of agreement about the unavoidable bits for Australia and NZ – temperature rise of 1 to 6degC, more and harsher droughts in Australia, up to 74cm in sea-level rise, up to 25% reduction in waterflow and up to 20% increase in salinity in the Murray-Darling Basin, and so on. Many Australian ecosystems are already at the edges of their ability to cope – and the projected rises will bring both economic systems and food security to that edge. Vulnerability to change is particularly concentrated in a few hotspots – and rainfall reductions mean that those hotspots include Perth, Melbourne and Sydney!

Chris Leigh, Head, National Climate Change Policy, UK Environment Ministry: “The great thing about emissions trading is that emissions are a global problem, and any reduction by anyone anywhere is worth having, so the trading causes those that can do it to do more than they have to, and sell the excess to those that find it hard, and that outcome is worth having.” Actually he said that in the bar last night, but I’m sure he’ll say something similar in his speech!

Chris Leigh pointed out that the UK Energy White Paper of 2003 calculated that the cost of getting the target 60% reduction in GHG emissions for the UK was less than 2% of GDP, which was forecast to grow by 200% over the same period. Uk targets are for 105 of energy to come from renewables by 2010, and double that by 2020. The long list of actions and programs under way in the UK threw into sharp relief Ian Campbell's claim that Australia leads the world - in fact, in the Q&A following Chris' talk, someone (all right, it was me) asked which Australian leads the UK would be following, and didn't get an answer (but did get a laugh). The Eu emissions trading scheme is seen as the main policy instrument for getting to the Kyoto targets and beyond - the UK national scheme achieved its 5-year target in the first year. Chris saw emissions trading as a complete win-win: for the regulator it avoids teh need for site-specific limits and simplifies enforcement, while for industry it provides flexibility and opportunities to gain from their own excellence.

Mark Mills drew an investment & short-termism lesson from Katrina: investments amounting to a few hundred million dollars in levees and pumps for New Orleans had been put off to make 'savings' at an eventual cost of more than a hundred billion dollars. He said that 40 years ago the average US stock investor held stocks for seven years, while US funds now turnover their holdings every ten months. Fund managers need to think long-term (by which he meant 5-10 years), and take climate change into account in an integrated assessment of companies' management quality.

Sean Lucy added a view that investment markets price the risk - and Australian investments could lose out because climate regulation is undefined because of not being within the standard global regulatory framework, and thus will be seen as inherently riskier.

In teh last session of the day, representatives of the energy, water, and grain industries all agreed that the basic science of climate change is accepted, and the what is needed now is more granular and refined local forecasts of longer-term impacts.

David, thanks for all the feedback from the conference. As an aside what I find interesting is the lack of comment from other Webdiarists on this thread on an issue which is of more global importance than the "war on terror" or "Paris burning". Perspective is a wonderful thing.

Preview of days three and four:

Wednesday gets hard to cover as the conference splits into four separate streams: observations, sequestration, adaptation and mitigation. But first we get a few more contributions on impacts in Australasia, where once again the Kiwis have the edge over Aussies in terms of getting their abstracts in on time.

Andy Reisinger from the NZ Environment Ministry says: "New Zealand is too small for its own domestic actions to make an appreciable difference to global climate change in terms of absolute emissions. ... Key challenges and opportunities for New Zealand include non-CO2 emissions from agriculture, biomass as both a
renewable energy source and as a carbon sink, and the development of wind and wave power. Agriculture makes New Zealand’s emission profile
unique, and viable mitigation options will be not only of domestic but global significance." What he means is that sheepfarts are more characteristic of NZ than energy use – I’m sure that can be reprocessed into a few jokes.

The Measurement and Observations stream pulls together a lot of what has already happened, with papers looking at the impact of frequent fires in the Australian bush, at direct measurements of greenhouse gas buildup in Europe, a CSIRO study on sea-level changes – essentially confirming the IPCC TAR estimates, and a BoM National Climate Centre study of impacts in Australia:

"Annual mean temperatures have generally increased throughout Australia since 1910, particularly since the 1950s ... The post-1950 period shows a marked decline in annual rainfall along the eastern seaboard. Regional cloud amount variations tend to correlate highly with rainfall changes ... Work has only just begun to attribute causes to the observed climate changes in Australia. Nevertheless, the observed changes appear to be broadly consistent with those expected under anthropogenic climate change."

There are also a great wodge of papers on this stream which are submitted and printed but without time to be delivered and debated, the most interesting of which looks at the increasing incidence of extreme weather events in Australia, notably droughts. There is also interesting stuff on El Nino and sea-ice variations.

The sequestration and adaptation streams have a lot of stuff on using the excess carbon to grow bigger trees – and show some serious limitations to our ability to use these mechanisms to slow the change. Some of the important quotes:

" reforestation has the potential to reduce the projected increase in Australian temperatures in 2050 and 2100 by as much as 40% and 20%, respectively. This cooling effect, however, is highly localized and occurs only in regions of reforestation. Our results therefore hint that the potential of reforestation to moderate the impact of global warming may be significantly limited by the spatial scale of reforestation. In terms of deforestation, results show that any future land clearing can exacerbate the projected warming in affected regions of Australia." Pitman (Macquarie Uni) & Narisma (Wisconsin)

"Saturation of sink mechanism such as CO2 and nitrogen fertilization are likely to take place within this century. Saturation of carbon pools such as regrowing forests in abandoned agricultural land are expected to take place within a few decades. ... Preliminary analyses indicate a risk over the coming century that may be larger than 200 ppm of atmospheric CO2, rivaling the expected release from fossil fuel combustion (Gruber et al. 2004). Such a massive release of greenhouse gases would result in higher concentrations of atmospheric CO2, accelerating climate warming, and potentially stimulating even greater losses of carbon from vulnerable pools. The risk of large losses from these pools is not well known, and is not included in most climate simulations. The combination of the saturation of sink processes and pools, and the destabilization of vulnerable carbon pools over this century is likely to result in a strong reduction of the net terrestrial carbon sink by the end of this century." Canadell & Raupach (CSIRO)

Heather Keith et al (CSIRO) report that drought and insect attacks can more than overcome the effect of increased carbon on tropical forest growth – potentially seriously reducing one of the few positive feedback loops in the climate change models.

"Temperature thresholds for coral bleaching vary with ambient water temperatures along the Great Barrier Reef and thresholds for coral mortality are only ~1degC higher than bleaching thresholds. ... The recent 1998 and 2002 bleaching events caused growth hiatuses in massive corals that appear unprecedented in their centuries-long growth histories." Lough et al (Aus Inst of Marine Science)

Cowell & Jones (Sydney Uni) report that current models potentially seriously underestimate the coastal erosion effects of climate change impacts on sea levels and wave climates.

"... climate changes are likely to significantly alter the cropping boundary in this region of South Australia. There was a smaller probability of viable crop zones expanding inland and a greater probability of the line of viable cropping moving south than was indicated in the earlier analysis by Reyenga et al. (2001) due in part to more pessimistic rainfall scenarios." Howden (CSIRO) and Hayman (S Aust R&D Inst)

... and the really important question of the impact of climate change on Australian wine production: " projected regional temperature increases, described in climate change models (OzClim), applied to a vine growth model (VineLOGIC) and indicate compression of the growing season, earlier budburst (in
most cases), later harvest, and more compressed harvest in future climates." Webb, Barlow & Whetton (CSIRO & Melbourne Uni)

The dominant theme of almost all of these papers is a worrying one. Each of these (and many others I haven’t singled out to quote or paraphrase) can be summarised like this: "We’ve studied this part of the problem in more detail, and on balance, it looks like the outcome is going to be a bit worse than we thought." Just about every refinement of the climate model predictions looks a little optimistic. There is a dearth of good news. Can we hope for good news from the fourth stream, which is concerned within mitigation – what can we do to change the outcome?

"Current trends for the PV industry, including steady price reductions, rapid technical improvements and very high (>50%/yr) sales growth, show that photovoltaics can economically replace coal for electricity generation over
the next 40 years. ... Australia has a relatively strong, but declining, position in the global PV industry. BP Solar produces about 4% of the world’s solar cells in Sydney." Andrew Blakers, Centre for Sustainable Energy Systems

Gonschorek et al from the Dresden University for Technology look at interim technologies for cleaning coal power stations: " As a result of the Kyoto Protocol and the National Allocation Plan (NAP) for the German energy sector also coal power plant operators are being forced to take measures in reducing their CO2 emissions. However, there is a dominating position of coal power on the German energy market that cannot be replaced in the near term. For future security of supply, the number of modern coalfired power stations in Germany will even have to increase due to the phase-out of nuclear power within the next 15 years."

In sum – a few interesting possibilities for exploitation that may become very important in the future world – and where Australia’s lack of action on climate change is potentially going to leave it dependent on importing the technology from others in future. I’ll probably attend this stream and hope to hear something more encouraging!

Eight different streams on day four – must be some sort of exponential series that would have become unmanageable by day five, so they had to cut the conference off at this point ...

Of the wide variety of presentations and posters, two in particular caught my attention:

"Facing Reduced Winter Rainfall in Southern Australia" (Timbal et al): External natural forcings (i.e. solar variability and volcanic eruptions) do not explain the rainfall decline in the South-West of Australia. Anthropogenic large-scale atmospheric forcings (i.e. greenhouse gases, aerosols and ozone) were very likely to have contributed to the SWA rainfall decline. Localized anthropogenic influences (i.e. land clearance) may have been an additional factor contributing to the rainfall decline in SWA. The recent rainfall decline in SEA is broadly consistent
with future climate change scenarios. All the climate model projections used in these studies point toward a further rainfall decline over the coming century, across a range of IPCC emission scenarios. The magnitude of the projected future rainfall decline varies considerably amongst models and across scenarios. Overall, it is of the order of magnitude of the past rainfall decline. While the recent observed decline is restricted to May to July, future projections suggest that future rainfall decline will not be limited to this period but will affect the entire southern “wet season” from May to October.

So, in brief, what we’ve been experiencing over the last few years wasn’t the drought, that was relatively speaking the wet bit – the drought to come will be worse ...

And a final word on the views of future voters for the pollies to worry about, from a study of high school students by a group from Edith Cowan Uni in Perth:

"... Students believe that the greenhouse effect is real and causing global warming, and they expect the government to enact strict laws to reduce greenhouse gas emissions and sign the Kyoto Protocol."

Day three report

Session on surprises and extremes:-

Will Steffen (Aus Greenhouse Office): "Abrupt changes are characteristic of the earth's systems - you get no response to a gradual change for a long while, then a threshold is crossed and and you get rapid change - and the hysteresis loops on these are such that they often don't come back to the original state when the forcing change is removed."

Penny Whetton(CSIRO): "You can have BOTH more floods and more droughts in response to a change in mean rainfall."

An interesting interactive session gathering views of the audience (71% of whom work essentially full-time on climate science), with feedback and revoting to concentrate the minds. Key result: 81% of those present think that the UNFCC aim to restrain climate change below dangerous levels is already a lost cause. Specifically, that number think that a rise in mean temperatures of 2degC (or a rise in CO2 above 450ppm) will be dangerous to human lives and systems - and those numbers get exceeded in almost all projections. Two specifics also brought up in other sessions: the Great Barrier Reef will almost certainly bleach annually then die at those temperatures, and the Greenland Ice Sheet will start on an irreversible melting trend over the next few centuries (for a 7meter sea-level rise) at somewhere between a 2degC and 3degC rise.

Adaptation sessions:-

Peter Cowell (Sydney Uni): "At predicted sea level rises for this century, coastal recession at Byron could be at the order of 150meters back from current coast. Apply that analysis to the projected developments of northern NSW and southern Queensland, and you could have a lot of very expensive real estate and high-rises out at sea: we're creating our very own potential New Orleans scenarios."

Brian Sadler (Indian Ocean Climate Initiative) gave some instructive history: at Greenhouse 1987, there was controversy on working on a scenario that showed waterflows in SW WA falling 40% by 2040 - most people still thought that the drop from 1969 on was a drought blip. By 1996 it was becoming clear that that 40% drop had already been exceeded - and in fact had already been exceeded from 1969 on. Dealing with that change cost more than $1Bn. Q: what other impacts that we are cautious about predicting for the future have already happened or are now inevitable?

Which takes us on to Measurements and Observations, where we get one potential answer:-

Mike Raupach (CSIRO) reporting on satellite-based studies of vegetation cover: "the series diverge from the rainfall data and history over the last few years of the drought, showing a loss of cover and resultant loss of carbon uptake that actually exceeds Australia's total GHG emissions."

Thanks for an exec. summary of very depressing stuff.

Do you know why Aurora - Victoria's landmark sustainable community being built at Epping (by the Government's own developer VicUrban) is suddenly now being touted on the website as "just a 35 minute drive via the Western Ring Road and Tullamarine Freeway" and not 'every house less than 800 metres from the railway station' which it's original blurb said - about a year ago I think. What are they doing?

I actually thought the State Gov. was onto something brilliant here and have been following the website with a view to possibly living there sometime in the future - and now it's not looking quite so fabulous and innovative - John Thwaites introductory speech at the conference was spot on, but who is actually going to lead the way?

Is anybody talking at the conference about behaviour change and how it happens?

David, great work, we need to put Climate Change on every agenda. It has the potential to wipe out the human race. It is by far the biggest threat we will face this century. We are like children playing with fire, with no idea of the consequences of our actions.

The future of our grandchildren is already looking bleak. Without a modern economy humans survived for thousands of years. Without a life supporting environment all life will end. It's the enviroment that should be our main focus.

Our minds are full of terrorism and IR reform, while the main threat goes under reported. Well done Webdiary.

Maybe I'm too much of a "pure" scientist, but I was a bit disappointed that the terms "sustainable" and "sustainability" were tossed around with little or no discussion of just what "sustainable" means. I went around asking a number of the speakers who used those words just how they defined them. Stabilisation of atmospheric CO2 at a set target level? Equilibration of anthropogenic carbon fluxes with natural uptake rates?

No straight answers. One speaker I queried even went so far as to suggest it was kind of a "feeling".

There needs to be a national discussion of what is or is not "sustainable" if we intend to have acheivable and measurable goals in environmental policy. Maybe that could be a theme for Greenhouse 2006.

David Roffey notes, "81% of those present think that the UNFCC aim to restrain climate change below dangerous levels is already a lost cause."

I just got back form the Greenhouse2005 conference. It was great to meet David face-to-face. Thank you David, for your excellent reporting from the meeting. As a "pure" scientist I don't often get to hang out with policy-makers, but I think it is increasingly vital for us to learn each other's lingo.

An important point that I think was not made explicit enough is perhaps not so much that the UNFCC mitigation steps are a "lost cause," but that we have already "locked in" at least some of the effects of human-induced global warming. Two reasons:

1) the long residence time of anthropogenic CO2 in the atmosphere. Even if we were to "unplug" society from fossil fuels today, we will be living with much of the already-added greenhouse gases for centuries to come. The geochemical processes that regulate the CO2 uptake timescale are an important insight from the Earth System science research community. A related impact is the inevitable and inexorable acidification of the oceans accompanying the uptake of anthropogenic CO2, with ecological consequences we are just beginning to understand.

2) Much of the radiative imbalance already locked in is in the form of elevated temperature in the upper layers (top few hundred meters) of the oceans. Again, this warmed water will continue for at least decades to re-radiate infrared, and transfer latent and sensible heat to the atmosphere. And it doesn't take much - the top meter of the ocean has approximately the heat content of the entire atmosphere.

Partly for reasons like the above, and partly because some of the observed warming may well be due to natural variability, adaptation strategies must be part of the mix of policy responses to the anticipated warming impacts, as some of the speakers pointed out. Many don't like to use the word "adaptation," because it sounds too much like "giving up" on mitigation. We are going to need both adaptation and reductions in emissions.

I'll add a few more comments later. Thank you again, David.

Too right, Will - Ian Campbell even used sustainable in the phrase "rapid and sustainable economic growth", and probably what he meant didn't have anything to do with the climate at all.

Great summary so far. I've been waiting for the 'more to come' that's promised. Will a summary of the Thursday talks be posted?

David: The key messages I took out were in the preview - I had to leave Melbourne to get back to Sydney during the day on Thursday, so didn't get in to listen to much. Anyone else who was there who wants to add impressions welcome to do so!

Hi David Roffey,
Your article has piqued my interest. I will admit that I have had my figurative 'head in the sand' for a bit on environmental issues.
I have some questions which, I hope, will not make me sound too ignorant!

1. Could the lack of posts here (apathy?) as mentioned by Sean Hefferon be a reflection of the enormity of this global issue? It all just seems so hard to tackle - like when you have the whole house to clean but can't face it and go shopping! (OK, maybe that's just me!)

2. What about the traction that people like Michael Crichton get? I am sure you are aware that Michael Crichton has a well-researched book of fiction out, called State of Fear, which scientifically pooh-poohs global warming. I find myself just confused by the various conclusions drawn from scientific statistics.

3. Finally, how much of the recent problems in Australia, like drought and increasingly high temperatures, are caused not so much by global factors but by national (thus more easily reversed) issues like land clearing?

Thanks Will and David for such comprehensive and interesting feedback to my questions!

A small addition to Will Howard's remarks re Michael Crichton's "well-researched" book. It's an interesting paradigm that you can make a book look well-researched if you list lots of references in the back, even if you show no sign of having read the references, misrepresent the conclusions of the referenced material, and plain lie about some of the facts - most particularly in misrepresenting the process of debate when the science was less clear, eg saying that early climate change reports were massaged to make the conclusions more clear, when those actually present at those meetings say that the science was significantly watered down by the deniers. See, for example, the critique here.

Mardi Black writes: "Your article has piqued my interest. I will admit that I have had my figurative 'head in the sand' for a bit on environmental issues.

"I have some questions which, I hope, will not make me sound too ignorant!

"1. Could the lack of posts here (apathy?) as mentioned by Sean Hefferon be a reflection of the enormity of this global issue? It all just seems so hard to tackle"

Hope you and David don't mind my weighing in here with a few comments.

It is a hard issue to tackle. In part because the problem is global in nature, and because long time scales are involved it's easy to be distracted by more immediate problems.

Though global warming may indeed turn out to have huge impacts I heard very little talk at Greenhouse2005 about the immediate and local environmental benefits of reducing fossil fuel emissions. Leaving aside for the moment global climate change over the next century - taking steps to limit fossil-fuel emissions would make cities better and healthier places to live almost immediately.

Some of this could be done by energy efficiency measures that make economic sense regardless of environmental considerations - what Victorian Environment Minister Thwaites called "low-hanging fruit." Such "no-regrets" energy-efficiency steps must be weighed against the costs of mitigation by disposal - geosequestration for example.

"2. What about the traction that people like Michael Crichton get? I am sure you are aware that Michael Crichton has a well-researched book of fiction out, called State of Fear, which scientifically pooh-poohs global warming. I find myself just confused by the various conclusions drawn from scientific statistics."

One word I cringe at hearing used at conferences like Greenhouse2005 is "skeptic," to describe the pooh-poohers (with all due apologies to loveable teddy bears). On one level authors like Crichton are doing what all of us should do - he is raising healthy doubt and debate about scientific issues. All well and good, and the way science should work. But critics like Crichton are in danger of committing the same error they accuse the scientific community of - adopting the assertion that global warming predictions are wrong and/or exaggerated, that the consequences of global warming will not be deleterious, and that the costs of reducing fossil fuel emissions will be economically and socially harmful. Perhaps they are correct - but this is becoming an article of faith among the critics. So I suggest they are not "skeptics" at all, but "deniers" or perhaps "contrarians."

Crichton and others also level the accusation that the scientific community, as represented by such bodies as the IPCC, have politicised science and have become attached to a cult-like belief in global warming. This argument is a loser for several reasons: first it can't be proven, and devolves into an endless and unwinnable "pissing contest." (Webdiary has had one or two of these if you want to see examples).

Second, I think it's plain wrong. Climate scientists overall have come to the conclusions we have on the basis of the evidence (from model output and observational data) before us. Is it possible the scientific community is incorrect about global warming? Yes. Though my own reading of emerging data suggests it's unlikely.

As an aside, another word I cringe at when used in the context of science is "consensus." Crichton is absolutely correct when he criticises the use of this word in science. We should never argue any issue on the basis of how many scientists believe something or other. The process of science has nothing to do with consensus. All it takes is one scientist with a solid argument, and the data to back it up, to prove a million others wrong.

Which leads me to my third point. Critics like Crichton misunderstand the sociology of science. Scientists are constantly looking to overturn paradigms as a way of making their names. If I had solid evidence right now that the idea of human-induced global warming was wrong, I'd publish it immediately, have my picture of the covers of Nature, Science, Rolling Stone, and Sports Illustrated, and be famous.

The media also misunderstand science, and tend to give equal weight to contrary views, even in the absence of equal weight of scientific evidence behind them. This is because "balance" is an important value for journalism. Balance is indeed important for the coverage of social and political issues, on which consensus must be achieved, but is not so relevant for science.

"3. Finally, how much of the recent problems in Australia, like drought and increasingly high temperatures, are caused not so much by global factors but by national (thus more easily reversed) issues like land clearing?"

There are both local (land use, irrigation policy) and probably global (climate warming) processes operating to drive regional problems like drought. How much, if at all, global processes like warming will affect, say, drought in any given region is still a big question mark. But it is likely that global warming will shift the baseline distributions of temperature, for example, in such a way that we will experience extremes like heat waves at greater frequency than at present, and there is already evidence that this is happening. Though it's impossible to pin any one extreme climate event on global warming (Hurricane Katrina, French heat wave, European floods, etc) we are at risk of exacerbating their probability and intensity. And again, some data are beginning to suggest it may already be happening.

I hope this at least begins to address your questions.

PS. I had to leave the conference Thursday morning, so missed the final day's presentations.

We heard a lot about sea-level change at Greenhouse2005, including the excellent paper by Church et al on the effects of volcanic emissions of sulfate aerosols on decadal sea-level trends.

Paradoxically, increased accumulation of ice on inland areas of continental glaciers in Greenland and Antarctica has been working against the trend of rising sea-levels. Near-term, this pattern is consistent with global warming delivering greater snowfall to the interiors of the ice sheets as the edges melt faster. Two papers in Science this year document these observations.

Johannessen et al report on Greenland Ice Sheet mas balance changes, and Davis et al report the Antarctic Ice Sheet changes. See also the review by Vaughan in the same issue.