Radio-quietness and optical-darkness as environmental credits - notes based on a colloquium presented to CSIRO ATNF, October 30, 2000

Transcription

1 Radio-quietness and optical-darkness as environmental credits - notes based on a colloquium presented to CSIRO ATNF, October 30, 2000 Abstract Michelle Storey CSIRO ATNF PO Box 76, Epping, NSW Australia 1710 A radio-quiet area is one with very low levels of background radio-frequency radiation. As use of the radio-frequency spectrum is increasing dramatically, radio-quietness is a rapidly diminishing resource. Freedom from radio-frequency interference is important for many purposes, and it will be especially important for future radio telescopes to be located in areas where the radio-quietness can be preserved. The increases in size and number of human population centres are also affecting optical-darkness throughout the world. Over the next few decades, the increase in artificial light levels will mean that the Milky Way will disappear from view for many urban dwellers and optical light interference will be an increasingly serious problem for optical telescopes throughout the world. Radio-quietness and optical-darkness are of value to many different groups in society. It would assist in preserving radio-quietness and optical-darkness if their value could be defined and quantified, and incentives established to encourage private companies and governments to preserve these natural resources. In this document, the current mechanisms controlling electromagnetic pollution will be outlined. There is international interest in forming radio-quiet reserves and Australian work being done towards achieving this is described. The usefulness of environmental credits schemes in protecting electromagnetic-quietness is explored. 1. Disappearing electromagnetic-quietness Use of the radio-frequency spectrum has been increasingly rapidly and is likely to increase even more sharply in the future as we move further into the information age. For example, the rate of increase in mobile phone usage is expected to continue for many years yet. What is more, the vision in the telecommunications industries is for people to have easy access to wireless connection to the internet on their laptop computers. Transmitting this much data requires much more bandwidth than transmitting voice. The growth in these industries will put even heavier demands on spectrum use. Radio-quietness, that is, lack of background radio-frequency radiation, is now fairly rare on the Earth's land surface. However, Australia, and especially Western Australia is relatively unpolluted compared with much of the rest of the world. Australia has a natural advantage when it comes to radio-quietness and so Australia is in a special position with respect to the preservation of radio-quietness.

2 Australia's low population density also means it has an advantage in the natural resource of optical-darkness. A paper by Cinzano et al. to come out soon in MNRAS indicates that by the year 2025 the Milky Way will not be visible from anywhere in Italy if current trends continue. Already nearly three-quarters of Americans can't see the Milky Way. Many people are going through their lives without seeing the dark night sky. The stars were one of the first inspirations for abstract thought. They probably played a major part in inspiring the way that humans first started to think abstractly. Most people find the dark night sky with the Milky Way spanning across it an awe-inspiring sight. Maybe we have evolved to. It is a huge cultural loss to the world if the night sky effectively disappears from view. 2. Mechanisms and examples of current work protecting electromagnetic-quietness Optical-darkness The International Dark-Sky Association, based in the US, works to increase public awareness of the issue of light pollution. It has about 4000 members from countries all over the world. Their message is that as cities grow lights are needed at night for safety and security, but there are huge savings to be made in light pollution and energy usage if sensible lights at used. The IDA is not just made up of astronomers. Their membership reflects the various concerns over optical light pollution: Environmentalists, interested in not wasting greenhouse gases. Dr Dave Crawford, Executive Director, IDA, estimates that 2.5% of Australia's total electricity production is used for night-time outdoor lighting, and probably 30% of this lighting ends up in sky, which is expensive and wasteful in money and greenhouse gases. Astronomers, professional and amateur Light pollution is increasingly affecting astronomy. Urban light glow from cities even several hundred kilometres away can affect optical telescopes Angry neighbours Glare and light spill from badly designed lights certainly helps to raise awareness of the issues. Animal conservationists. For example it is estimated that large lit towers in the US result in the death of 2-4 million birds per year. Migrating birds are attracted by the lights in towers and fly into guyropes. Bright lights are also known to upset sea turtle hatchlings and also other nocturnal animals.

3 From the above it can be seen that for optical light pollution there are a few well-defined issues: urban sky glow glare light trespass energy waste The IDA consider that there are also well-defined solutions: Better designed lights, aiming the light down where it is wanted, and using the right amount of light. Using the right type of light. Lighting Plans, as produced for Sydney, in which sensible lighting is thought about. Taking special care near to optical telescopes. For example, around Siding Spring Observatories in Coonabarabran, the Orana Regional Environment Plan exists to help reduce artificial skyglow around the observatory. It identifies critical light thresholds in the area which should not be exceeded. The current plan is under review at the moment. An important point is that for optical observatories a lot of light pollution control needs to be done on a local level, but general education even in distant cities is important to improve the light glow problem. Radio-quietness There are also regulations controlling use of the radio spectrum. The long travel distances of radio waves is what makes them useful for telecommunications. It also means that international regulations are important, both to prevent countries' operations from interfering with each other, and because telecommunications is a global business requiring international coordination. The spectrum is managed on an international level by a specialised agency of the United Nations, the International Telecommunications Union, by means of the Radio Regulations. The Regulations contain a table of frequency allocations, in which spectral bands are allocated to services according to their needs, applications received and a lengthy negotiation process. Allocations are decided at World Radiocommunications Conferences, roughly every 2 years. Many bands are allocated to more than one service on the assumption that they can share the band. For the purposes of spectrum management, radio astronomy is defined as a radiocommunications service, and has been allocated protected bands and some shared bands. Once allocated, the frequencies for particular services are assigned to individual users in each country. In Australia this is done by the Australian Communications Authority, which is linked to the Federal Government. Some frequency bands are auctioned. At the

4 latest auction of a parcel of spectrum, in March 2000, the high bid total exceeded AUS$1 billion. Interestingly, the companies investing in telecommunication equipment are, on the whole, supportive of the coordination process. Markets for telecommunications devices are global. It is an advantage to a company, for example, if their mobile phones can use the same frequencies all over the world, as it simplifies the manufacture of the phone unit. So the rules are mainly followed and the process of allocating frequencies works reasonably well. As well as allocating frequencies, the ITU is responsible for setting the regulations restricting interference. Transmitters allowed to radiate in one range of frequencies should be careful that their emissions don't spill over too strongly into other frequency ranges or other places. Unfortunately, economic considerations can sometimes lead to companies making decisions detrimental to the protection of radio-quietness. There are many groups for whom radio-frequency interference is a serious issue. The interference control function of the ITU is an important one, for example, for aircraft operators. They are very keen that their allocated part of the spectrum is free from interference so that the radar equipment that tells them where they are can still function. Freedom from radio-frequency interference is also important for remote sensing. Remote sensing has been useful for monitoring things like reduction in vegetation on land and in sea, earth plate movement, making maps for erosion control and many other applications. It is very important that the spectrum does not become too crowded for remote sensing. Other groups sensitive to radio-frequency interference include deep space tracking and, of course, radio astronomy. Radio-frequency interference is especially important for radio astronomy, as radio astronomy receivers are the most sensitive. It is also true that we don't yet understand all the implications of living in a radio-loud world. There is much research being done on the effect of electromagnetic radiation on biological tissue. Radio-quietness may be very important in ways we don't fully know yet. But like many aspects of our environment, we don't throw them away just because we don t yet fully understand their value. It may be important to preserve some areas of Earth as radio-quiet to act as control-environments. This is one reason why radio astronomy has an important role to play in general in the radio-quietness issue. Radio telescopes are a very sensitive probe of radio-quietness and can act as an early warning system for radio-frequency pollution. The ITU does allocate some frequencies for purely passive use for radio astronomy, but we know that the frequencies set aside for radio astronomy are increasingly interfered with. In addition, for some time those frequencies have not been sufficient for radio astronomy.

5 Modern radio receivers for continuum work are wideband for high sensitivity, but the width of some of the existing allocated continuum bands are much less than astronomers really need. With more sensitive equipment, and this is especially true for the nextgeneration radio telescopes such as the Square Kilometre Array, astronomers will be able to observe red-shifted lines from very distant objects. Thus the protected band just corresponding to the at-rest frequency of important spectral lines is no longer adequate. Astronomers need to make observations over a whole range of frequencies to test theories of modern cosmology. A few radio telescopes have negotiated extra protection from radio-frequency interference around their observatories, which are good case studies for what kind of extra protection is feasible in the current system. For example, the new Byrd radiotelescope in the US, that was recently opened, sits in a radio-quiet zone that was established in Fixed transmitters radiating close to the Green Bank Observatory have to consult with the Observatory before operating. Another successful example of extra controls being successfully negotiated is that the NSW State Government through the Department of Minerals works with CSIRO to minimise interference at the Parkes radiotelescope near Parkes in NSW. However, these kinds of regulations only apply to fixed transmitters. There is very little protection against mobile transmitters and satellite signals and the number of satellites is increasing. 3. International Recognition of the Importance of Protecting Radioquietness The need for better protection from radio-frequency pollution across the whole radiofrequency spectrum has been recognised at various levels internationally. In astronomy, the IAU has a Commission to investigate the protection of astronomical sites and a Working Group to study ways to protect radio astronomy from radiofrequency interference. At a higher level, the OECD Megascience forum set up a working group on radio astronomy in 1997 to help plan radio astronomy on the international level for the next years. In its report the group recognised the need for radio astronomers to have access to large parts of the radio-frequency spectrum, and the threats to such access from increasing levels of interference from space-to-earth transmissions by telecommunications satellites. One of the solutions they looked at was a Green Tax whereby some of the money governments earned by selling spectrum should be fed back into research on ways to reduce interference.

6 Since then the Megascience Forum has been reborn as the Global Science Forum and within the Global Science Forum a one-year Task Force has been set up to ensure that "radio astronomy (whose progress is in the public interest) and telecommunications companies (who provide satellite services that benefit the public) can find a way to coexist." They are to investigate technological solutions, regulation and radio-quiet zones and draw up a road map of long-term solutions for consideration by relevant national and international bodies. The United Nations Office of Outer Space Affairs has also recommended that Member States work on solutions for protecting the environment from electromagnetic pollution. Radio-quiet Reserves The international groups referred to above have suggested that the idea of establishing radio-quiet reserves be investigated. An international radio-quiet reserve would be a world-recognised area that could be made available for various investigations that required a radio-quiet environment. It would be important to choose an area that was already radio-quiet, because it can be politically and economically difficult to request that existing services be stopped. And the reserve would need regulatory or legislative protection preventing activities from starting up nearby that would generate unacceptable levels of radio-frequency interference. This would include regulations to restrict satellite broadcasts over the reserve in frequency and/or time. A radio-quiet reserve would be of significant international value and there are already organisations around the world that would be interested in placing their sensitive equipment on a radio-quiet reserve. Inland Australia may be a suitable location for a radio-quiet reserve. Because the population density is so low inland Australia is still radio-quiet. What is more, in inland Western Australia, not only is it quiet, but there is good access to the sophisticated infrastructure that facilities would need. There are also large parcels of land being set aside for conservation. The needs of a radio-quiet reserve are probably compatible with conservation needs and it is possible that high-technology equipment requiring radioquietness could happily be located in a conservation reserve. Australia's geographic isolation means that it can introduce special rules preventing radio-frequency interference that won't affect other countries operations. And inland Australia is one of the few radioquiet places on the Earth that aren't covered in metres of snow in the wintertime. At the moment, ATNF and the Western Australian Government are actively working towards establishing radio-quiet reserves. Current work includes; designing and building sensitive equipment for measuring radio-frequency interference developing a program to measure radio-frequency interference levels in inland Western Australia defining acceptable standards for a radio-quiet reserve working on the regulations or legislation required to establish a radio-quiet reserve in Australia

7 For example, one important aspect of the above investigations is to determine how you would define a radio-quiet reserve and define radio-quietness. It is hard to go back in time and ask existing services to cease. (Although an interesting difference between radio pollution and other environmental pollution is that you can make a big improvement by just "pulling out the plug". Radio-frequency pollution is a relatively tractable problem compared to many environmental problems. But this is only true for land-based emissions, which is one reason why it is important to get radio-quietness on the agenda now, before too many badly designed satellites are launched). What is of most interest to radio astronomy (and others who require radio-quietness) are the areas of frequency spectrum in between licensed transmissions, where there might be unwanted signals. The measurement program being developed will measure the strength of emissions in these areas of spectrum, as well as the strength of licensed transmitters. The quality of a radio-quiet reserve (or radio-quietness anywhere) will realistically depend on how much spectrum can be defined as being free of licensed transmissions and how radio-quiet these areas are. 4. Summary of status and importance of electromagnetic-quietness Firstly, electromagnetic-quietness is under threat worldwide and extra protection is needed. The existing mechanisms are supported but are not really adequate given modern pressures on the spectrum. The establishment of special reserves, upon which electromagnetic-quietness would be protected, is being investigated. Secondly, electromagnetic quietness is worth protecting. Areas with radio-quiet and/or optically-dark skies are of value to many different groups in society: to Government if a government can provide sites where the electromagnetic-quietness is preserved than they may attract high-technology facilities to those areas to the public the starry sky and the science of astronomy are culturally important and capture the public imagination. People want astronomy to continue. As well, the full benefits of a radio-quiet environment are not yet known. It may be important to preserve some areas so that radio-quiet studies can be conducted. to scientists. Astronomers need interference free skies so that modern telescopes can operate at their maximum potential. 5. Environmental Credit Schemes Some of the benefits of electromagnetic-quietness mentioned above can be assigned an economic value. There are clear economic benefits that flow from hosting high-

8 technology facilities, and from using more energy-efficient lighting. There may be quantifiable tourist benefits to areas that are electromagnetic-quiet. However, the cultural benefits that flow from being able to still see the night sky and still learn from astronomy are harder to quantify, and have to be assessed alongside the support offered to other cultural activities like the opera and the arts. This is where environmental credits may be able to help. Environmental credit schemes operate by giving a value to an environmental asset or an activity impacting on the environment. The purpose is to make companies and governments financially accountable for the environmental damage they do, and welldesigned credit schemes provide incentives for improving the environment. Using environmental credits schemes environmental issues can be included with the other economic considerations of companies and governments, as they should be if we are to have a sustainable future. The Australian Federal Government is very keen to involve companies in natural resource management and doing this is one strength of environmental credit schemes. Admittedly electromagnetic quietness is not high on the government's agenda yet as a natural resource issue, but it should be. So can environmental credit schemes be used to help preserve radio-quietness and optical-darkness? There are several kinds of environmental credit schemes already operating. And the best way to begin to understand how they can operate is by looking at a few examples. One of my favourite examples of an environmental credit scheme is airspace over Sydney. Too many skyscrapers creates an undesirable environment on the ground. There is a maximum amount of airspace that can be taken up over buildings in Sydney. Each building site has a certain no. of "floors" of airspace assigned to it. If you want to build a taller building then you have to purchase airspace credits from someone else who has spare credits. Developers buy airspace credits from heritage buildings that aren't using all of theirs. So heritage buildings benefit from being low, developers have to pay more to build huge skyscrapers which affect the levels of shading etc in the city and the total amount of building crowding in the city is limited. That is a very simple scheme, but its purpose is clear and its main advantage is the main advantage I think of all environmental credit schemes - it rewards overcompliance. There is a benefit in doing better than the minimum required by regulation. If your building is lower than the maximum allowed you can gain by selling credits to others. There have been a few environmental credits schemes in the US for various pollutants but one of the biggest schemes was created in It is more complicated so illustrates more of the complexities.

9 It is called RECLAIM - Regional Clean Air Incentives Market. The market was among electric utilities in the areas surrounding LA, and the main commodity was sulfur dioxide - targeted for its role in causing acid rain. Electric utilities are given yearly allowances to pollute, based on what emissions were from The government is gradually reducing the allowances each year, in order to gradually reduce total emissions. Each allowance gives the right to emit one ton of sulfur dioxide. At the end of each year, each utility must prove to the bureaucrats that it holds as many allowances as it emitted tons of sulfur dioxide that year, as measured by devices called continuous emission monitors at the end of stacks. If it doesn't, it is fined $2000 per extra ton emitted and faces an equal reduction in its allowance baseline for the next year. Utilities are allowed to sell and buy allowances as they like as long as they satisfy those requirements. Before the credit scheme air-quality control worked through the government setting regulations and policing them. The problem is that it is usually in a companies best interests to do the absolute minimum required to satisfy government regulations, and policing is hard. You can start to see the benefits of environmental credits schemes (and the problems) when you look at what has happened to the RECLAIM scheme. It is still early days - the scheme only applies so far to the largest utilities - the other have to join in But sulfur dioxide emissions are falling far ahead of the EPA's schedule. They are about 30% lower than expected. Prices for the 2 main reduction options - low sulfur coal and scrubbers to eliminate sulfur at the end of the stack - are also falling. The program has increased competitiveness in pollution-reducing industries and has created innovation in new ways to eliminate sulfur. This means that when the smaller companies join the scheme the cost of improving emissions is already lowered from what it was. The above is one of the good things about credit schemes. If one utility can reduce emissions below the number of allowances it holds for that year, it can make money selling the extra allowances to a utility that couldn't reduce enough. A company can benefit by doing better than the minimum required by regulation. In fact, all companies can. If another utility can cut emissions more cheaply than your utility can you can reap the benefits of their knowledge by buying their extra allowances. So innovation is encouraged all over. Another positive side effect of the allowance trading has been the rise of environmental charities. Private individuals can impact on large companies to make them reduce pollution. For ~$150 a member of the public can make sure that a whole ton of pollution never enters the air, by buying that allowance. Schools have bought pollution allowances, parents have given them to children as wedding presents, and, I like this one,

10 Northeast Utilities, one of the polluters, donated a large number of allowances to the American Lung Association in One of the problems with the scheme is the fact that local polluting pockets can build up. In a rich area a company might reduce emissions and sell those allowances to a utility in a poor area that can then pollute more. You need to be careful with environmental schemes that you don't just move the pain around. In spite of possible problems I think that environmental credits schemes have sufficient advantages that we should look at whether they could be used in preserving radioquietness or optical-darkness. In a way, optical-darkness already is associated with an environmental credits scheme. You have to pay for the electricity that you use to light things. The problem is that electricity is too cheap, and advertising your building by shining silly lights at it at night is still sometimes considered a good and economic thing to do. So if we wanted to reduce the urban glow from Sydney, what would we allow companies to trade in? What would we measure? One of the challenges with environmental credits schemes is what to measure. What is the allowance? Often the actual environmental impact is too hard to measure, so easier equivalents, called surrogates, are used. But it is important to be measuring an appropriate thing. In the same way that it helps to understand existing credit schemes by looking at real examples, I think it might help to understand the implications of environmental credit schemes for electromagnetic-quietness by inventing a few examples. I emphasise that these are conversation pieces only. I'm not claiming to have the solutions here. But I hope it encourages some feedback. PONDS, Preserving Our Nighttime Dark Skies Let me introduce the first environmental credits scheme, as far as I know, for optical darkness. The AAO/ASA defines and maintains, using international standards, a list of suitable light fittings and types. Any company can use such light fittings (still in accordance with existing regional plans). But any large company (start with the large ones) can only emit a certain number of kwatthours at night using non-approved light fittings. The allowance is x kwatthours of non-approved lighting, measured by what they have installed. A certain number of allowances is issued by the Government each year, roughly in line with what is used now. Then you allow trading in the allowances.

11 If a company can decrease its use of allowances by turning the lights off, buying approved fittings or putting smaller bulbs in, then it can sell its saved allowances to someone else. Of course, astronomy is such a trendy field that a company would be able to use its dark-sky-friendly lighting policy to raise its public image. And there is room here for public ethical investment. McDonalds in a country town might be located near an important amateur astronomer's observatory. The townspeople could get together to buy the lighting allowances from McDonalds, and McDonalds could use the money to install more dark-friendly lighting. Maybe McDonalds could donate its allowances to the amateur observatory, using the taxbreak that would be created for such donations, to pay for the dark-friendly lighting it could then install. The government could decide to gradually increase, decrease or keep steady the total number of allowances it allocated in an area each year. The advantages of such a credit scheme over straight regulations are that there are incentives to use approved lights, and incentives to do more than the basic minimum, the use of non-approved lighting is controlled, and there are incentives to do innovative things with lighting. Would the Government like it? I think so. They would be encouraging innovation without having to do much themselves. They would be involving the public and private companies in natural resource management. Would companies like it? The main advantage for companies is that it is better for clever companies than straight regulation, and as long as there are some clever companies, then less clever companies can still survive too by buying their allowances. A shop in Coonabarabran might be cross to think that its non-approved lighting was going to be restricted from expanding in the future, but as the town grows, its current lighting allowance becomes very valuable, and if it can be clever with its lighting it can sell its allowances to a new business. So there are advantages for companies in the first instance which may make the introduction of such schemes more popular. New ideas for preserving radio-quietness The considerations are a bit different for radio frequencies. Geography helps. You can be shielded from large and distant towns because radio waves don't scatter off the atmosphere back at you. On the other hand, you might have high-power transmitters beaming at you. Satellites striving to have their signals reach every part of the Earth may transmit in your direction. And the telecommunications industry is a huge and fiercely competitive business.

12 We also need to decide what it is we want to preserve. What kind of radio-quiet reserve do we want? One issue here is that the radio-quietness required for radio astronomy may be very different from general radio-quietness if we allow the effect of interference mitigation. For example, a company could acquire environmental credits allowing it to radiate if it also funded interference mitigation research which enabled astronomers to remove the signals. You could end up with a very loud radio-quiet reserve given how successful interference mitigation techniques are proving to be. I think there is value in attempting to preserve an area as a general radio-quiet reserve for various purposes, but with regard to global telecommunications, I think it would be more fruitful to try and protect radio-quietness in general, rather than radio astronomy in particular. The telecommunications industry is large and competitive and special considerations just for radio astronomy may not be heeded. Any scheme to protect radio astronomy should be part of a larger scheme. It is important to note that, where radio-frequency interference is concerned, the aims of the various interested parties are not necessarily in conflict. The telecommunications industry wants the ability to send and receive clearly the maximum number of signals as economically as possible (at least not more expensively than any other company has to do). Radio astronomy wants to receive as little interfering signal as possible and so do other passive users. The public wants minimum exposure to excessive levels of radiation combined with maximum access to services provided via the telecommunications industry. Governments want to have services provided for their voters, while raising money from selling spectrum. This combination of aims is best reached by only sending signals of the required frequency where they are wanted. Other techniques that reduce the effect of unwanted signals, while necessary and important, will suffer from diminishing returns, for both industry and radio astronomy, as the spectrum becomes more crowded. Being "cleaning up the oil after you've let it spill on the beach" solutions they should not replace the better solutions of avoiding the transmission of unwanted signals in the first place. The best way to send signals just where they are wanted is with optic-fibre or, failing that, technologies capable of most efficiently using spectrum and capable of steering multiple beams and nulls. Everyone would benefit if mechanisms could be devised that encourage the use of "clean technologies" that minimise the transmission of unwanted signals and maximise efficient use of the spectrum. A few possibilities:

13 One way to encourage the development of "clean technologies" wherever possible is to devise mechanisms whereby companies using these technologies are compensated for the extra cost. Rewarding companies that use environmentally friendly solutions is one of the features of well-designed environmental credits schemes. The following is one possible way that environmental credits could help compensate companies. A company could be assigned environmental credits on the basis of the technology it was using to transmit signals. Different technologies could earn different numbers of "clean technology credits" depending on how well they satisfied the criterion of only sending signals of the desired frequency to the desired place. Optic-fibre and phasedarrays with steerable nulls, for example, would earn a large number of credits, because they lead to minimum unwanted signals. Equipment with filters installed where signals were transmitted would earn more credits than equipment with filters installed where signals were received. To acquire, from a national government, a license to operate, a company would be required to own a defined number of credits. A company using a best-practice technology would have excess credits that it could sell to other companies using less desirable technologies. Thus companies would be encouraged to use "cleaner" technology, and companies using "clean" technology would benefit by having excess credits to sell. The Government could also sell (auction?) extra credits if they were required and that money could be invested into radio-frequency interference reduction research. Such a system is designed to operate at the national level of issuing licenses rather than the ITU level. This would enable the scheme to respond more quickly to rapidly changing technologies and be flexible in the ways that current wisdom recommends for environmental credits schemes. The ITU structure is optimised for getting issues precisely worked out. It would be hard for its Working Group structure to reach decisions on the timescales required. It is a feature of most environmental credit schemes that surrogates are used as credits because the environmental feature being protected is too difficult or complicated to easily measure. The surrogate here is "clean technology". Which technologies to include and how many credits they earn for a company could rapidly evolve and would require careful and continual assessment. This scheme has the advantage that it need only be implemented by countries for whom preserving radio-quietness is a priority. It could be tuned to especially protect radio-quiet reserves as licenses leading to radiation over such areas may require extra clean technology credits. Another possible mechanism for encouraging the development of technologies using phased-arrays would be if countries allowed companies, radiating with phased-array antennas that could steer nulls over radio telescopes, to radiate in some of the

14 protected radio astronomy bands. This is allowing more use of spectrum, but hopefully more intelligently, while encouraging the development of technology in a useful direction. Governments could also use affirmative action by giving preference in issuing licenses and accepting bids for spectrum to companies either using cleaner technologies, or able to demonstrate that they are investing in R&D into cleaner technologies. The main advantages of environmental credit schemes is that they encourage innovation, and encourage over-compliance, while making companies responsible for their environmental impact. Australia is a good place to choose to try innovative schemes for long-term protection of electromagnetic-quietness, as we are still rich in these natural resources.