While I was mulling over this variability this morning, I listened to Macca on the ABC. I always get a bit upset with him, but maybe that is ok. I think he tends to be very simplistic in some of his environment comments, or maybe it is just that he lets people I don’t agree with air on the show. So that is not a bad thing, I can write my blog, he can have these people on the show. Anyway, this morning someone was having a go at wind energy and arguing that we would still need coal fired plants to pick up the peak demand. The main concern of the caller was the visual damage of wind energy to the landscape.

There is another regular caller to Macca’s program (however not during today’s program) who I think put the finger on the spot: Dick Smith has argued that the problem with solar was all a problem with storage! Nobody has yet figured out to make efficient and convenient batteries. I think he is right. I think we do have a storage problem, not only in energy, but also in water.

All water our storage is highly inefficient. Evaporation rates from open water are extremely high in Australia. I just plucked these statistics for Lake Burragorang (behind Warragamba Dam and the main water supply for Sydney) of the Sydney Catchment Authority website:
• Capacity: 2,031,000 megalitres
• Area: 75 square kilometres

Average Daily summer evaporation from open water in the summer at Sydney airport (closest station) are between 6.5 – 7.5 mm/day. If Lake Burragorang is totally full (75 km2) than it loses 75*1000*1000*0.007 = 525,000 m3 per day this is (wait for it...) 525 ML/day. I know this is only 0.02% of the storage capacity, but it is still 525 olympic swimming pools per day to use the popular translation. In a week, this means it loses 0.14% just from evaporation. At the moment, the lake is about 54% full and lost 8,020 ML this week of which approximately (54%*525*7 =) 1984 ML or about 20 - 25% is due to evaporation. That is of course very roughly calculated, but it indicates the magnitude of such losses.

This gets me back to the storage problem. Clearly we have a problem with storing water. If we can work out a more efficient way of storing water we would be able to save 20 – 25% of our water. But what are the options. For urban water, we can recover the 20 – 25% simply by recycling, but other options are possible. For agriculture, the issue is more interesting. One of the often raised options is using groundwater aquifers to store water. This involves pumping water into the ground in times of plenty and pumping it out in times of scarcity and for example rainwater harvesting also falls under this heading. This plan has its merits but does need some careful consideration. One of the major issues is one of water quality: In Australia much of the groundwater is often lower in quality (saline) so picking your spot could be difficult. In addition it is a bit like catching fish, labelling it as yours and throwing it back: There is no guarantee you might get the same amount of water back as you put in, so planning becomes a bit of challenge.

For agriculture, just storing more soil water is still another option to maybe be able to use irrigation less. How this would be done, I currently don’t know, but I think it worth working on. Somebody contacted me earlier on this blog that he had a solution in this area, so I think it might be a case of “watch this space”. As this person had commercial interests, I referred him to the South Australian Water Industry Alliance who provide an excellent forum for such interests.

Storage of water in both natural systems has also many more interesting aspects. In particular, I think we need to understand more about the behaviour of soil water storage in varying climate. Something I plan to work on pretty soon (As soon as I can get these other papers finished!).

Using that same argument means we should also not sequester any carbon in soil. More carbon in soil leads to higher water holding capacity and this water will be evaporated and used by plants and thus leaving less water to run off and replenish the rivers. You can see the silliness in these arguments, again we would argue that we should not sequester more carbon in our soils because it will lead to less water in the rivers.

The other question I have is about how much water there was before humans removed trees and reduced soil carbon in the Murray Darling Basin. Maybe we have always been spoiled with too much water because the land was cleared and depleted of carbon.

Would increasing carbon levels increase the recharge to groundwater from soils? If increasing carbon levels lead to better soil structure it might lead to greater porosity and thus better drainage (or worse drainage depending on your point of view). This was demonstrated already on conservation tillage and in paddocks with erosion control banks. Paddocks under conservation tillage and with control banks had much higher water fluxes below the root zone than conventionally tilled soils. Thus more water to groundwater.

If you take the point of view that most of the shallow groundwater is unusable and that there is little connection from groundwater to surface water (i.e. rivers in NSW are losing rather than gaining) than this water is essentially lost to humans, or is it? Do we really understand enough about the connections between groundwater and surface water.

Which landscape would be more resilient? We tried to argue this in a landscape with rainwater harvesting in India (essentially forcing the water to the groundwater) and found that increasing groundwater storage made the irrigated agriculture more resilient, but we could not yet answer this for the whole landscape.

Maybe it is all a question of equilibrium. Yes, initially we will see a reduction in streamflow due to greater storage and use of water in the landscape, but in the end it will reach a new equilibrium.

You can see my problem. I cannot believe that the answer to more water in the river systems (“to save the Murray”) has to be increased runoff and this banning tree planting and maybe carbon soil sequestration. If that is the argument than the catchments should all be concreted over.

Peter's ideas have recently been gaining some momentum here and here, and I thought I should write a summary of my own thoughts about the visit and about what I think of Natural Sequence Farming and Peter's ideas. To start with the verdict: I think the core has some good ideas which are worth pursuing but these are also rather well known and embedded in existing knowledge. What is great is that Peter manages to communicate these ideas to a wider group of people than anyone else. I am not convinced that the overall concept should be accepted as the general rule for farming in Australia. I will explain.

I am convinced that modern agriculture has caused problems and has changed the hydrology of the landscape. Increased runoff and therefore increased stream velocities and erosion are symptoms of this. Dryland salinity has always been related to changes in hydrology, but as I have commented earlier, the views on the causes of dryland salinity have been changing. In fact, it is now more likely that there is a strong link between land degradation and dryland salinity.

Somewhat novel about Peter Andrews' concept is the idea of slowing down the water in the landscape and thus increasing the retention time. To some this is downright heresy. What is further novel is to use this water to increase biomass production and increasing soil carbon by mulching the biomass. Increased soil carbon in return will increase water retention and thus strengthening the cycle. The somewhat new part is the link between carbon and water, the rest is of course strongly embedded in conservation tillage. The link of using water more efficiently to produce more carbon is no entirely new. Another thinker in sustainability who has also been working on the carbon water link is of course Bill Mollison. I was reading Bill Mollison's books when I was still an undergraduate in Wageningen in the 1980's and spent some time studying biological agriculture. Many of the concepts Peter Andrews has come up with have also been raised by Bill Mollison earlier. What is interesting is that Bill Mollison is of course a die-hard greenie and Peter Andrews is more your stock standard Australian farmer. I think this is in fact great news: Peter is reaching a whole lot of people who will never read Bill Mollison.

Slowing down the water in the floodplain is a good idea and particularly the combination with increased biomass production, mulching and minimising the loss of nutrients does the trick. In the floodplain pasture landscape that Peter is working with this achieves great results. Whether we can grow wheat in that way is however a major question. In the end we would like some production from the landscape and thus we would like to harvest some of the biomass/carbon. The main thing to watch is of course the loss of carbon/nutrients and the replacement of those nutrients and carbon with biomass. This means that long term rotations and pasture/wheat systems are most effective, but as agronomists we already knew that from biological farming experiments in the Europe. The problem proponents of biological farming always ran into was the fact that such a system was not profitable and therefore not acceptable for the majority of farmers. Peter is arguing that such a system is profitable for grazing systems. I think it is as long as you can manage the loss of nutrients through production.

Slowing down the water in Peter’s system basically increases the buffering capacity of the landscape, or in other words, it creates a better resilience. This means you are able to manage droughts better, but you will have to watch your carbon stocks and rebuild.

Slowing down the water is of course heresy in light of the traditional thinking in dryland salinity. This will probably increase deep drainage and thus would traditionally be seen as a problem in relation to rising water tables. However, this paradigm is currently under scrutiny.As Dr. John Williams pointed out to me, the increased recharge in Peter Andrews' system also creates a shallow fresh water lens on top of any saline groundwater. This will work as long as the recharge is low in salinity. Any soils which are inherently saline or have high soluble salts (such as carbonates) will of course behave differently. So what will work in the sandstone and shale derived soils at Tarwyn Park might not work elsewhere if the parent material is more saline. I don't believe that the biological system will reduce the salt load. It can only do that if some of the salt is a nutrient based salt or if it gets stored in the landscape, to be released at a later point.

Slowing down water is also heresy from the level of the Murray Darling Basin, as this would further reduce flows in the system, similar to the effects of plantation forests. But again, we should ask ourselves, what was the original system. If white settlers have cleared the landscape, than this would have increased the flows into the system. All we are doing with increased landscape water storage is restoring some of the original flows. This is of course not good news for irrigators and Adelaide, but that might be inevitable if we want to restore the landscape. Tarwyn Park is in the Hunter, so it mainly affects the mining and the vineyards down stream in the Hunter. In a way, what the approach is doing is water harvesting and increasing infiltration and recharge.

So the core of Peter's ideas are embedded in existing and well established ideas about biological farming and about water harvesting. They are not controversial to me. It will work as long as you have low salinity soils, low salinity input water and a relatively flat landscape and you are close to a water source. It also will work better in grazing systems as the nutrient loss can be managed better. Wheat and other cropping systems would really have to think hard about rotations and carbon balances.

All the rest of the ideas from Peter are only layering around this core and some of it I really cannot see any use for, or I find a bit silly. Call me a heretic if you want, but at least I am honest. I am happy to be proven wrong.

The question I struggle with is whether we are not better off not growing any perennial crops at all. The specific nature of perennial crops is that they grow over several years and thus would need water every year, even if the need less water than an annual crop. In contrast an annual crop can be grown whenever water is plentiful.

In the Netherlands, a concept called “living with floods” has been developed. This concept is really related to flood management and not to irrigation. The concept says that it is better to accept that floods occur and thus that a river needs space (i.e. don’t build any houses on the floodplains) than to try and fight floods by increasing levees. I feel this concept is applicable in relation to irrigation water and crop choices in Australia.

A key characteristic of the Australian climate is the high variability (“droughts and flooding rains”), which means that the river will be dry for years followed by a massive flood. Climate change is suggested to bring even more of this variability. In the article that I mentioned above, we already calculated, based on the last 80 years of data, that good flows in the Lower Balonne river system only happen once in every 4 years.

What is more unnatural in such a system than a dam to collect runoff, what a typical human idea (or engineering idea)! Yes, dams and river regulation allow the river to be controlled and floods to be diminished and dry years to be overcome. But if the variability increases or changes the system is difficult to change (this is called resistant), exactly as we are seeing now: licences have been given out and investments (and bank loans!) have been made based on these licences.

Perennial plantings will now require water every year and are difficult to change (resistant) and so are huge investments in irrigation layouts which require regular annual profits to pay of bank loans.

What we really need is an agricultural system that is resilient, a system that can adapt to changes in the climate, from year to year and from decade to decade and from century to century. I feel that annual crops have a better opportunity to fit into such a system than most perennial plantings, as planting decisions can be changed from year to year and these crops can be interspersed with rainfed crops. Alternatively we could look for perennial plantings that do not need water every year (and might not give a crop every year). Such systems could harvest irrigation years in plentiful flood years, similar to floodplain graziers (and of course not harvest too much) and in the end we might not need dams at all! But this requires a total change in thinking, and I am not sure we can do this yet.

Free Blog Counter

Free Blog Counter

On the other hand, mining is the opposite of sustainable use of land, so we are caught in a difficult spot here. We should not discard the mining option straight away, as it is a matter of scale in time and space. The definition of sustainability is no longer helpful. In the definition of sustainability, there is reference to the well being of future generations. This means we need to identify whether the future generations are more assisted by digging up and selling coal and investing the money, or by the continued agricultural production.

Interestingly, the Greens have decided to take the side of agriculture, also not an obvious marriage given the amount of groundwater use and questions about agricultural sustainability in the area. The Caroona Coal Action Group also has not yet given up

I am taking a resilience point of view, this means that I am assessing the activities in terms of which is best able to withstand a shock. Surely agriculture activities would be more resilient than mining, but that is my opinion, I have no scientific proof. However, mining activities are vulnerable to currency fluctuations, global recession, and there are further technological and climatological risks. Agreed that most of the engineers have worked out ways to deal with most of the risks, but the risks exist. In contrast, I feel that Agriculture is relatively low risk, although modern mechanised agriculture has some of the same risks as mining. However, as an activity, there are more opportunities to continue agriculture after a major shock than to continue long wall mining, even without looking at risks to aquifers and water supplies.

Free Blog Counter

"By studying historical records for thousands of water bores across NSW, researchers from the NSW Department of Environment and Climate Change and the University of NSW have shown that salinity is traceable to rising groundwater levels."

Well we knew that, but I assume that is the reporter not getting it right. it started off much more controversial:

"CLIMATE and rainfall, not land-clearing, have emerged as the main drivers of salinity in south-eastern Australia, in a study that could overturn years of research."

Ian knows how to kick up a controversial story and this one definitely got the airwaves buzzing. Several people have contacted me and checked whether I read the story and wanted to comment. I promised I was going to write something on my blog about this.

If you analyse the rainfall data for the southeastern Australia over the last century or so then there is a distinct increase in the rainfall in the 1950 – 1970/80. This is particularly true for SE Aus, but is also true for the Murray Darling Basin. I have commented on this last year: see here

Given the strong connection between the shallow groundwater and the rainfall, you would expect to see a response and, yes, this means that expressions of salinity will worsen after high rainfall periods and in dry periods (current) will disappear. This has been noted and commented on by others, for example Dahlhaus et al. (2008), so in itself the debate is nothing new.

The comments that were sent to me concentrated in particular on the question whether this ignores the years of salinity research (about 30 years worth) that have been completed and which have indicated a connection between landuse and salinity. I think it does and it doesn’t. There are a few key points to remember in this issue:
1. Landuse , deep drainage and responses in groundwater levels are strongly coupled and thus it is obvious that climate variations will be observed in the groundwater tables and that as such it is not surprising that groundwater tables respond to climate. What the salinity research has shown us is that they will respond more under certain land uses than under others due to differences in deep drainage
2. The research by Prof. Acworth and his colleagues probably covered the last 100 years (at the most) given the availability of groundwater data. Land use change has been happening much longer.
3. The salinity research has shown that there is a wide variety of groundwater systems, some of which respond very quickly to changes in landuse (and climate) while others respond much slower. The seminal work by Ian Jolly (Jolly et al. 2001) clearly indicates that most of the groundwater systems are not in equilibrium and that changes in discharge and groundwater levels due to landuse and climate will sometimes take centuries to work through the system.
4. There is a difference in pressure responses and groundwater volume responses and sometimes it is difficult to disentangle these two effects on larger scales. Climate influences will work stronger on pressure responses as their input tends to be a larger pulse compared to changes due to landuse effects.

I can’t stress too much that the best approach to salinity is not broad brush, but case by case. There is a wide variety of geological systems, salt stores and processes. However, general hydrological laws will apply:
A. Changing one component of the water balance will affect the other components
B. Salt moves with water, if there is a store and water moves salt will move with it.

References
Dahlhaus P, Cox J, Simmons C, Smitt C (2008) Beyond hydrogeologic evidence: challenging the current assumptions about salinity processes in the Corangamite region, Australia. Hydrogeology Journal 16, 1283-1298.
Jolly ID, Williamson DR, et al. (2001) Historical stream salinity trends and catchment salt balances in the Murray-Darling Basin, Australia. Marine and Freshwater Research 52, 53-63.

1. Nature is fantastically self-restoring; it is an ecosystem at optimal functionality. This means that any impact that we might have tends to be local and gets immediately absorbed by the effectiveness of the ecosystem to absorb shocks. For example if we clear cut an area of forest, than its impact on soil, water and atmosphere is either minimal (but this only works if the area is not too large), or the ecosystem compensates this loss of functionality somewhere else. I find this difficult to believe, but it would be wonderful if true.
So as a result of this wonderful resilience of nature none (or few) of the actions of humans have any impact on the overall health of the ecosystem. As a result climate change is not induced by humans, as we can’t have that much impact on the climate

2. Alternatively, I think they have a great trust in human inventiveness and in the certainty of science: We will find solutions for all our problems. Don’t worry about climate change, even if this is happening it is not a problem. We have very smart scientists and we humans are fantastically inventive. As a result, whatever climate change is happening is not an issue, we can easily manage those problems. Don’t be so alarmist, of course we can deal with 1 – 2 C increase in temperature. Our science is advanced and we have already have lots if solutions like clean coal technology and cloud seeding. Another example: currently the temperature trends since 1998 do not agree at all with the predictions of climate change, so the science of climate change must be wrong. This suggests that they believe that all predictions in science must generally be very certain (even though they can be wrong). In other words, most scientific predictions are very accurate and predict exactly what is going to happen, ergo, if it does not exactly predict what is going to happen it must be wrong.

Particularly this last point baffles me, to me all science comes with considerable uncertainty (even the best predictions contain uncertainty). Forecasting the future is the worst, there are so many variables. However with the best available science we can make a general prediction of the future (plus or minus “a bit”). So you would never expect reality to exactly follow a prediction, you would expect it to follow a general (and in this case long term) trend.

I also do not understand the high trust in nature’s resilience. That is some wonderful system that we have, but surely everything can be broken. For a system to be highly resilient it needs to be highly interconnected. In addition, most highly resilient systems still have breaking point, and once it breaks there is no way back as the most resilient systems are also the most hysteretic.

Of course, I should post something like this without also pointing out what I believe in, however, I will keep you in suspense for a week. I promise to post next week my views on Nature, science and the universe.

One approach might that we say: Oh, that is great, so we don’t need to worry, Gaia will in the end sort us out. This means we will reach some kind of equilibrium sustainability, but the question there is: for how many people? If we are positive thinkers, and believe in our human technological and scientific capabilities, than this could be sustainability for the projected 9 billion people.

I am a bit more worried. Yes, I think we still have some time to experiment, but the clock is ticking. I wish I knew what time it was …. We have some estimates about what CO2 levels in the atmosphere might be survivable, but the current financial crisis has probably thrown out the projections a bit.

There are however many things that we still don’t know and those are the things I would like to research and am working towards. We really do not know how far we have to go until parts of the ecosystem collapse. We do not know how many species can go extinct before affecting the overall planet in a major way. Or in my case, what is the balance between vegetation, climate and landscape. Clearing vegetation leads to reduced evaporation and thus reduced moisture feedback. In the worst case, it leads to erosion and degradation. Reduced moisture feedback probably does not mean that there is less moisture in the air, it just does not generate rainfall and goes elsewhere.

In the end, this comes back to research into thresholds and resilience and that is what our current global carbon experiment is about: how far can we push the CO2 levels on the globe before the whole ecosystem collapses. Some would like this experiment to continue as they think it will never collapse. I would like at least to first find out whether we can reverse the impact.

I think the key thing that needs agreeing on is that sustainability is not the same as zero impact. This is because, as I argued during the debate, sustainability has a space and time dimension. So we can have some significant impact as long as this impact is alleviated in a different time and space, again this relates to resilience.

Overall sustainability remains tricky and seems to mean different things for different people. The debate will continue for a while.

In the mean time NSW is none too pleased, arguing that most of the water purchases for the Murray Darling Basin have taken place in NSW, and they are right. Funny thing is, while the federal government is buying surface water, NSW is selling groundwater because they have saved water by capping bores in the Great Artesian Basin and a small proportion of the water saved is offered for sale. There are some interesting questions here.

Rural communities are also none too pleased as they are worried about the social economic impact, something I have also eluded too in my blog. Others in the rural community are also not happy with the state of NSW in relation to the mining in the Liverpool Plains. And that has of course also to do with water, namely the groundwater in that area. So while NSW is making good progress with protecting the Great Artesian Basin they are willing to take a punt on the groundwater resources under the Liverpool Plains. Seems odd, doesn’t it?

On the balance, what is good and what is bad? I guess lots of rain is always good for farmers (unless you were just about to start the tractor), but what about the buying and selling of water. Most irrigation communities are worried about the large water buy backs. In essence their worry is purely from a socio-economic perspective. While all would like to see more water in the river for ecological reasons, it is how the water buy back affect the local communities that worries many. A large company such as Twynam Agricultural Company is a major employer, in particular on its irrigation properties in almost every NSW river valley. Selling the water can only mean less jobs.
In the mean time another gripe is that the “water for the future” program consisted of several components. The majority of the funding was to be spent on improvement of water use efficiency on farm. In the past, I have argued that this might not be the best way to spend money, but that is another discussion. Currently, the issue that many rural communities (and irrigator communities) have with the spending on "Water for the Future" is that spending on buybacks dominates and very little is spend on the on-farm water use efficiency programs. This is a pity, because, if we do not want to spend money on socio economic restructuring then spending money on improvements I water use efficiency might have the same impact: We are spending money in rural communities to stabilise and improve the local economy. It will not deliver a drop of extra water in the river, but it will help balance the money moving out of communities through the buybacks.

The last point made by several people is: But what about our food and fibre production? I don’t think that argument holds in terms of the buybacks as the water can always be diverted back to farming if needed. However it does hold in terms of mining leases on prime agricultural land. In this case, perfect agricultural land will be changed permanently due to mining. Although I am not too worried about food security, I think there is a deeper principle here. What should we choose: short term strong but (possibly) unsustainable gains (mining) versus lower income but (possible) long term sustainability? I believe that humans too often choose for the first as our planning horizon is too short. Yes, I know it is jobs, jobs, jobs, but that is the easy way out. What other way is there to generate jobs without digging up some fantastic farming country? That is without even worrying about the groundwater implications.

I was very glad to see that there will be an independent study on the impact of mining on groundwater resources.

The pattern of the annual flow data at Lake Eyre is curious, where have I seen that before?


I estimated the values of the graph and just out of interest plotted them against the annual mean rainfall for Australia for that same period on a graph. Aha, that is where I had seen that pattern before. It nicely follows the rainfall, but only above a threshold of about 400 – 500 mm annual rainfall. If we get anything more than that, the lake will get inflows for sure. Looking at the cumulative probability of exceedance of flows we can see that this is very skewed and inflows above 10 km3 only have a 10% probability of occurring. In other words, “one the average” flows above 10 km3 happen every 10 years.

Given that this is my understanding of utility, I will try to explain where things seem to fall over for me. From the above example, we could argue that we could include “the environment” as a player in our measurement of utility. It would come into this in two ways. One is where I am gaining utility from a “clean” environment, the other where “the environment” is seen as a subgroup in society whose utility also has to be maximised to achieve the overall optimal outcome. For example, I (and society and the environment) have a clear loss of utility due to the leaking of Chromium VI into the Parramatta river. On the other hand the company will lose utility if it has to clean it up. From what I understand from the story, the environment’s and society’s loss of utility weigh more heavily than the company’s and the company will have to clean it up. Here it seems like the story is pretty clear cut, we can see the yellow plumes, we can do something.

But is it really? I will first go to a less clear example. We have a river with plentiful water (for example in Northern Australia) and we have a plan for water extraction for irrigation (or to pipe it Perth for that matter). Clearly there is a gain in society’s utility due to increased food production, more drinking water, agricultural and possibly export wealth. There is a loss in the environment’s utility due to a decrease in water availability to the ecosystem. So an EIA (environmental impact assessment) needs to be done, so we can weigh the environment’s loss of utility against the society’s gain.

All sounds pretty good, but is this actually possible. My first argument would be that there is no way that the EIA would be able to capture all the actual loss of utility for the environment from extracting water. I am not saying that the outcomes are catastrophic; I am just arguing that Nature is too complex and our understanding of Nature is too limited to be able to capture all loss. Note that this does not mean that society should decide against extraction, I am only arguing that in this case we cannot calculate utility.

I think most of economics colleagues will now say, oh no, but you have got it wrong my friend, what we cannot measure, people in society might be able to feel, imagine or think through and those people might be so horrified that this results in a loss of utility which they might express by voting against, buying different products etc. Yes, that could happen, but do we really think that enough people would be able to do this for every environmental problem? And are we able to measure or calculate this utility? This is probably where I got lost in the economic theory.

It would still mean that someone out there can lose sufficient utility to capture exactly the real loss in utility in the environment. From my science perspective, I believe that we will always underestimate the actual impact that our actions have on nature, because there is absolutely no way we can understand all complexity. Not all of our actions have negative impacts, but we never foresee all the consequences. As a result we have to accept that all our decisions are anthropocentric (human based) and that we are not able to foresee our overall impact on the environment. We will always be uncertain about what our actions will result in.

Coming to think of it, I think that is actually not that strange. We often do not know what the overall result of our actions in human interactions is either; we are often groping around in the dark in policy, economics and social interactions. None of this is wrong, as none of us has a crystal ball.

My gripe is probably more with the presentation of maximising utility as a crystal ball, and to me it sometimes feels that way. As long as it is recognised as a theoretical concept in economics which can possibly guide our decisions than I am happy. We don’t ask anything else from Science.

Maybe I am a bit of a pessimist, but I generally believe that there is basically no win-win situation. We have to accept that we will lose something if we want something else. Agricultural management is in principle based on managing the biosphere to extract more than in a natural situation. The difficulty we face at the moment is that we are extracting too much and this has resulted in major losses of biosphere, so we have to take a step back and give something back. As a result, you can understand that I am pretty disappointed with the fact that Australia’s carbon pollution reduction scheme now seems dead in the water. I really thought we were finally going to do something.

That there is disagreement between scientists is not a strange thing and this brings me to the Faggion (1994) article. For someone like me, it is a very interesting article to read. It discusses how between 1870 and 1910 scientists in NSW were at loggerheads on the origin and behaviour of groundwater, in particular the Great Artesian Basin which had just been discovered. It must have been so confusing: here was water rising up from the earth under very high pressure (up to 200 m above the surface) and being very warm (50 – 60 C). Where did this water come from? Why was there so much pressure? Will the pressure drop? Given that western NSW was just being settled and was extremely dry, this water seemed like manna from heaven. They finally agreed that it was artesian (derived from rainfall) and that it therefore was not inexhaustible, i.e. pressures would drop if too much was extracted relative to recharge from rainfall. They had not yet figured out the age of the water and how long it took to travel from the intake beds in the Great Dividing Range to the mound springs near Lake Eyre. These complexities were added later.
What the story shows is that scientist argued and that evidence often pointed in both directions (i.e. both camps used the same data as supporting evidence). Because the problem was too great in complexity to be simply solved (an open-ended problem) the arguments raged for years.

You can see where I am getting to with my last article. This discusses the state of knowledge of the impact between the hydrological cycle and climate in 1992. Since that time we have progressed quite a bit further, but the debate still rages. Again, it is a complex open-ended problem with increasing complexity. I am interested in the article because it points quite clearly to the impact of land use on the climate cycle and the hydrological cycle, a point of interest that Mike Young and I share. If landuse is changed in a major way, and on a large scale (for example in the Murray Darling Basin), than this will change the continental climate, due to the shifts in the hydrological balance. Basically, Chahine (1992) argues that the earth’s climate will compensate through latent heat (evaporation) for changes in the albedo and radiative forcing. Fascinating stuff. If you combine this with the paper by McAlpine (2007), you can see how scary this gets and why we should start giving something back.

So how does this bring me back to Mike Young’s droplet and the engineers? And to future water management? The droplet argues that we should have a more adaptive management in water in the basin to manage the flows we have. That seems awfully reactive management. I think we need pro-active management and that seems to be some sort of restoration of the evaporation signature of the Murray Darling Basin. This might take 100 years, but will store a whole lot of carbon (growing trees). It will also reduce our flows in the river, meaning that we will have to do more with less water, but we have to do that anyway, and Mike and I agree in that.

References
CHAHINE, M. T. (1992) The hydrological cycle and its influence on climate. Nature, 359, 373-380.
FAGGION, A. E. (1994) The Australian Groundwater Controversy 1870-1910. Historical Records of Australian Science, 10, 337-348.
MCALPINE, C. A., SYKTUS, J., DEO, R. C., LAWRENCE, P. J., MCGOWAN, H. A., WATTERSON, I. G. & PHINN, S. R. (2007) Modelling the impact of historical land cover change on Australia's regional climate. Geophysical Research Letters, 34, L22711.