Towards a zero footprint architecture

Our decisions hold the key to this 21st century environmental enigma.

Is it really possible to go 'zero'?

Consider this. Every act and process putting together a building nowadays involves huge amounts of energy and impacts the environment. Let us assess a few areas:

1. Utilisation of materials to build- virgin, reused, recycled or otherwise
2. Extraction of the raw materials
3. The transportation of these materials
4. The manufacture of building materials..
5. The generation of direct and indirect wastes, and pollution.
6. The consumption of materials in operations- water, energy, fuel, etc.

When we look back, not too long ago, say just over a 100 years, we find that there were hardly any emissions of any kind involved in the usage of materials for building. Energy for extraction, or the synthesis of materials involved the usage of higher degrees of human labour to compensate for any other form of energy. This was so stark that the construction of large institutional buildings like forts, palaces or temples resembled the efforts put in to build the dams of today. Having said that, in India we are still a labour intensive construction industry... which is not altogether a bad thing considering the great amounts of employment that it generates. What is required though is a drastic improvement in working environments and skill levels.

Surely some CO2 emissions and environmental fall outs did result from some construction activities (the institutional causing greater damage than the vernacular). For example, the burning of bricks used as building blocks has remained much the same as today, with vast amounts of wood/coal being used to fire the brick kilns. Sun dried bricks, or Compressed Soil Stabilised Blocks, or, rammed earth walls, using lime as a mortar, need no firing and use solar energy. If we are able to tap into renewable energy sources for construction or material production, we could make material production and usage emission free. 

An iron ore mine in South Goa that has eaten into the biodiversity rich Western Ghats!

Extraction is altogether a different matter. The energy of extraction today involves the spending of large amounts of energy for mining, excavating, etc. In earlier times, the low demand (non-institutional) dictated the rate of extraction, but a market driven new world economy exerts too much pressure here. To keep up the indices of performance, more material is extracted. I have written about this in another blog post. The methods of extraction have also changed significantly. Granite is now blasted out of the ground, while one method from the past used in some places even today , involved the insertion of wooden dowels into the ground and soaking them with water, which would expand during overnight cooling and crack the granite in the desired size. The extraction of stratified rocks like marble and sandstone has seen a similar change, with the inclusion of heavy machinery  against the use of skilled manual labour who would split the marble along its grain, by driving wooden/metal  wedges into the rock. Today, more often than not, vast areas of forests are cleared to reach these raw materials. This leads to the destruction of CO2 banks and the release of these green house gases due to the rotting of this cut-down biomass. Also, forests are sponges of the earth and ensure a healthy water balance, by keeping the ground well hydrated and holding together the top-soil. Once removed, the land gets parched and erodes the soil of essential minerals for sustaining plant life. Dependent fauna are the immediate victims. The massive scale of raw material extraction today has impacts that affect the region beyond the immediate context. I am not too sure if there can be a zero impact extraction method as an alternative, but perhaps we should look at the kind of raw materials that we consume as a start. A larger use of waste as a raw material, easily re-fashionable building components, a more spread out usage of material according to geographic regions might help.

With a booming modern day construction scenario, such sights aren't
that uncommon, but what is not visible to all is the energy consumed!

Today's building materials have often travelled many a mile to get to our construction sites. We do not bat an eyelid about this specially since all aspects of our lives have ceased to be limited by matters of distance. Being a relatively large nation, geographically speaking, industry has spread its tentacles close to their source of raw materials. Vast transportation networks and corridors constantly feed stocks close to our sites relentlessly. The effort to pick up these materials for construction is usually from the local outlets, obscuring completely the energies that go into getting those materials there from the points of manufacture. There are other forces that define the distances our building components travel...  Global aspirations of the project initiator may attract faucets all the way from Europe, or, kitchen equipment from Italy, or, Paints from Korea and so on. This very global economy sometimes also creates a seemingly  improbable yet financially lucrative incentive to by overseas.... a whole lot of building materials today (as many other goods) originate in China.
Over a 150 ears ago, such sourcing would have been the exclusive habit of the kings!! The masses would invariably build what was available locally, therefore more affordable. While it is easy to talk of the use of locally available material, we ought to compliment that with supporting market incentives, upgradation of skill-sets & technologies, and most importantly a sustained education and advocacy effort to sensitise people to the ills of stretching these geographic limits. A few disincentives like a transportation emission tax could provide an encouraging nudge. 

Manufacturing today is a complex science, involving complex systems, resulting in complex products.... and ever so often a set of complex (read harmful) residues/wastes. In the yearning for 'long-lasting' solutions we have taken complex engineering to higher and higher levels, and devised materials that are made of  unbreakable bonds. Be it the plastics that cater from protective sheeting to transparent screens, the laminates for flooring or cladding, the chemical veneers for roof and wall covering/protection, the non abrasive tiles that span our floors (and walls),.... the resulting side-effects are equally strong in their environmental impacts. High energies needed for manufacture of these complex bonds result in high CO2 emissions, Chemical by-products take a toll on our air, soil and water as emitted pollutants, and the products themselves end up leaching poisonous chemicals into their built environs over their lifetimes. For example, Volatile Organic Compounds like lead, Mercury and Arsenic are spewed by most chemically coated surfaces from paints to laminates to carpets. Bituminous compounds used in waterproofing (and in road tops) break up relatively quickly and leach into the ground, contaminating the local aquifers. Perhaps the trick is to stick to near natural states of materials, like earth for construction, bamboo/wood for building structures, lime/mud for wall plaster, stone as cladding and building block, etc. Physically fashioning a natural material to suit an application involves no further chemical contamination, whereas chemically altering compounds is saddled with these toxic extras.

The sun sets behind the smoke stacks of one of our many industrial backyards.

There are scores of materials today that claim to be energy efficient. But we have to put that in context. Energy efficiency in usage (while good) need not be energy efficient in manufacturing. Also, energy efficiency only implies a betterment from the current benchmarks, and does not mean that they are energy positive. Furthermore, when one refers to a zero energy building, a common term today, one normally means the net energy consumption during its lifetime, which does not include the energies that went into the making of the building and its building components. Depending on building use, the energy in building (or embodied energy of building) could be equal to the total energy consumption of the building in its operations. Thus the often used term for zero energy building refers mainly to the operational energy equation, and is not therefore truly zero energy.

I have covered the topic of consumption in an earlier post, and it takes very little to understand that consuming less would have a proportionately lesser footprint. So far, we have seen that we have big decisions to take in the choice of materials to reduce the upstream environmental impacts during extraction, transportation, manufacturing and utilisation. Is it possible to occupy a truly zero ecological footprint architecture? Many examples exist, in our past, in our rural hinterland and in some truly commendable contemporary projects, that hint at the fact we can get there. The necessary ingredient for that though is a complete overhaul of our thinking and gaining insights into our every decision in the building process, from design to occupancy. I remember a Star Trek episode which spoke of a race that chose a passive and low tech living against the high-tech unbridled alternative, for very much the same reasons... to preserve a way of life! 

The Sustainable Housing Complex for ACC

Sometimes, even the biggest giants surprise you.

ACC, one of India's super brands and the oldest cement company had set a mandate of going green. Over the last years substantial changes from their composition of cement, to the manufacturing process, and even the way they built their own corporate office were initiated. The mantra in their plants was non-polluting and the greater production of pozzolonic cement. For their buildings were set the goals to achieve the highest standards of green building practices.

Along these lines, ACC had initiated the process of building their entire residential campus for their staff colony of their cement grinding plant at Kudithini, in Bellary, Karnataka, as a sustainable campus. M/s Ashok B Lall Architects, ABLA, from Delhi were roped in as the main Architects for this project. Mr Lall's office went about putting together the remaining team for the project (services consultants, energy consultants, LEED/GRIHA certifcation consultants, Landscape consultants, and last but not the least, the Construction Management Consultants. That is where we (IGH) came in.

As construction management consultants, we had the task of enabling, coordinating and managing the various outcomes of the various consultants. To boot, our programme was by our design, carried out as 'Sustainable Construction Management Consultancy'. By this definition, we took up cudgels on the behalf of the architects to ensure that the entire development, its building construction systems and methods employed would be resource efficient and therefore occupy a low ecological footprint.

The ACC Greens Village, as it was later named, occupied the western section of the larger 240 odd acre campus of the Kudithini cement grinding plant. Area for this campus was demarcated and occupied about 50 acres in all. Going beyond the mandate of designing and building residential quarters and some amenities (amounting to some 83,000 sft), this Village of sorts also incorporated into the brief

• a huge afforestation programme,
• food sustainability- which saw the development of a sizable farm, a cattle shed (for milk) and a fish pond
• rainwater management, harvesting and recharge,
• energy sustainability which saw the incorporation of biomass gassification infrastructure, supplement by woody biomass from the afforestation programme, and a bio-methanisation unit supplement by the dung from the cattle shed.

Our engagement on this project can be highlighted in these following sections:

Development of a prototype structure

The first part of our involvement as a member of this team saw the suggestion of building a prototype structure that would embody all the construction systems envisaged and also serve as a benchmark of quality for the remaining construction to follow. This would also have ensured that all obstacles and hiccups (design or execution) would be limited to just this structure, with smooth sailing on the larger project.

An alternative to RCC slabs

Mr Lall's office had designed some exquisite buildings that were based on solar passive design principles and were based on an innovate thermal management of the interior spaces through cooling tubes, insulation and aided hydration for those hotter months. Essentially, the building type can be described as being sandwiched between cooling tubes to the east and west, and verandahs to the north and south. The cooling tubes had a wind scoop from the northwest and an exhaust side towards the southeast. The verandahs had openable insulated screens that would remain shut during the hotter months (trapping air which would retard any heat exchange) and be kept open for the more cooler months.

One feature designed originally by the ABLA was to pass cool air from the cooling tubes through the slabs of the building, therefore resulting in a deeper RCC slab and with PVC pipes as passages to this air. We suggested an alternative- a pre-cast system, which involved the placing of semi cast latticed RCC rafters and hollow pre-cast blocks that were cast to fit the needed profile. This system involved the usage of lesser concrete than the RCC slab originally suggested, and also meant the reduction in the usage of steel in the slab. One added advantage was the doing away of any shuttering for the in-situ pouring of concrete. Another was quality control. After scrutiny of the system and a visit to a vendor's site, the architects were convinced and the system was chosen.

The rafters were latticed t-beams, and were semi-cast (2 inches of the base was cast first) on the ground and cured. They were then lifted and set in place, using nothing more than a team of four (these rafters were limited to maximum spans of 4 metres). Props are placed at 1.5 metre intervals of each rafter to ensure that no buckling or cracking occurs during construction. The pre-cast filler blocks were made using a custom template on an egg-laying type block making machine. Once cured, they would be lifted into place and set on the protruding flanges of the t-beam. Above this, a grid using welded mesh is placed to cater for any upward thrust. Apart from that in the rafters, this is the only steel in this kind of slab. Concrete is then poured over this to create a layer of 1.5-2 inches above the pre-cast blocks.

As a total, this building used about 1.4 kg per sq ft of steel.... A saving of about 40% steel when compared to a conventionally built structure. (this is in spite of the extra steel used in the RCC tie bands as seismic area construction, and in the precast slabs used to cover the cooling tubes).

Finalising a resource sensitive block

Bellary has predominantly black cotton soil, so the architects had originally opted for a site-cast concrete block for the masonry. I remember having pursued a more resource efficient block from the get go.... We collected soil samples and tested them in Bangalore (including at the IISc Civil Engineering Department). We got mixed results. Then a eureka moment... the Kudithin cement plant had been procuring hundreds of tons of GGBS (ground slag) from the nearby Jindal steel plant. GGBS is a by product of the steel manufacturing process. This was used in the cement that the plant manufactured... and was a pozzolonic material. We checked this out as a substitute at the IISc lab and found that we got incredible strengths even at a high 40% GGBS constitution of the block (the remaining being quarry dust and cement).

The block manufacturing was initiated at site using manual presses, which resulted in the manufacture of over 800-1000 blocks per day. These blocks were designed as 200 thk blocks and were to meet a density requirement of about 2.0 kg/cm3 to ensure a requisite thermal mass design to meet the thermal dynamics of this design. While the contractor employed for the construction of the prototype building was very experienced in soil block making and other alternative construction technologies, we encouraged and roped in three other vendors in block making using the GGBS mix. They would come in handy for the block making for the main project. Despite the expensive procurement rate for the GGBS, we were able to make these blocks more economical than the originally envisaged site made concrete blocks.
An interesting anecdote is that ACC, which had originally initiated building several kilometres of boundary wall around and within their campus with concrete blocks, shifted to using these GGBS blocks.... as it also made financial sense. A big impact of the interventions of the entire team of architects and engineers.
Another impact of building use these site made GGBS blocks, were that we could control quality and due to the good consistency of these blocks, we could afford to leave the walls exposed. Of course this meant that we had to opt for some surface pointing to secure them from any untoward seepage. Being grey, this did mean that an interesting enough aesthetic had to be developed to avoid getting a dull appearance..

Reclaimed timber

At IGH we had been keen to push earlier thresholds of using alternatives for regular timber for doors and windows. The small scale merchants of old timber doors and windows in various parts of Bangalore had always intrigued us and showed promise if only we could use this wonderful resource at a larger scale. These merchants are small time operators and mainly cater to smaller requirements.

The properties of such a timber source is that it can be used as is, if the door/window component is in good shape, or has to be re-sized, planed and finished to suit the new design. The wooden members bear the scars of nails and pegs, that would have been removed in the resizing exercise. Care has to be taken to develop an aesthetic that incorporates these blemishes and scars (which add character to the wood), or, to mask them appropriately. A big benefit of the exercise is that wood can be considered as super treated wood due to both the more thorough treatment processes followed back in the day, and due to the natural conditioning of this wood over the years. Chances of deflection are extremely rare in the use of such wood. Another important aspect to consider while using such wood is that since these merchants don't segregate the wood based on wood type (neem, mathi, teak, sal, etc) the raw material is a mixture. The most one can do (with ease) is to ensure that each door component, is made from one wood. One can tone, or, paint over to bring an element of congruity over a much larger usage.

Most of this wood is sourced from areas that are seeing great urban renewal.... mostly smaller towns of Karnataka. The primary source is a demolition contractor who then re-sells these wooden components to these reused timber merchants.

ABLA was thrilled to have this value addition. The challenge was to find sections that were as wide as the designed double shuttered windows.... we just about managed to get a guarantee of the sections of that width for the entire project. We prepared a list of reused timber merchants and ensured that we could manage scale by using a group of vendors, instead of depending on just one. Eventually, the architects chose to paint these windows and doors with a colour scheme inspired by how rural homes around Bellary always articulated their doors/windows in resplendent colours. 

A lower energy floor

Bellary is situated at the border of central Karnataka and Anantpur in Andhra Pradesh. It is a dry arid belt, and is close to some repositories of granite (in Karnataka) and some slates (from AP). Originally, a granite was considered for all the flooring, but after discussions it was felt that we could achieve a further lower embodied energy footprint by opting for a pigmented cement floor. The logic was that since cement mortar forms the base of all stone floors, we could achieve this by simply eliminating the stone above, and rendering the cement floor well.

The challenge, however, was to get good skills to make these floors. We chose to go for an ochre coloured oxide floor, which would create a nice contrast to the grey surfaces of the GGBS blocks.

We went through a number of mixes of cement and different yellow oxides, and finally settled on the use of white cement instead of grey, and a minimum thickness of 3 mm of this mixture. This brought out the colour of the floor, and avoided the revealing of the lower grey cement base due to the additional thickness of this coat.

It had been common practise to use glass or brass strips in these concrete floors (also seen in cast in-situ mosaic floors) to control expansion cracks. This was not appealing to the design team, so an interesting, but more labour intensive method of laying this pigmented floor was chosen. The floor areas were divided into a 1m x 1m grid of panels. Alternate panels were cast first, and once set, the remaining panels were cast. Yes, this did take a bit more time than casting this floor in one shot, but it also meant that chances of large size cracks would be limited as one could consider the casts as limited to a smaller size, and therefore leading to a controlled expansion and contraction... leading to lesser cracking. Apart from a vibrant aesthetic and being a more resource efficient alternative, this also saved the client money as a pigmented cement floor costs much less than a stone floor.

Oh... those high energy industrialised tiles (vitrified, ceramic, etc) were not even an option!!

Bamboo engineered wood replacing plywood

As per the thermal management design of this building type, adjustable screens were provided in the verandahs. The purpose of these screens was to provide an adjustable thermal barrier when needed. These screens were panels that were built around a metal frame. The core layer was insulation and it was clad with plywood and a thin veneer on either side. To reduce the usage of conventional wood (plywood being a contributing factor) we proposed the usage of Bamboo mat board, BMB, as a replacement to the plywood. BMB is an engineered product that is a glued laminate of several bamboo mats. As BMB was attractive by itself, one did not require the use of a veneer over this. BMB is akin to marine grade ply and some manufacturers make versions that are external grade, with a protective UV resistant coat. Bamboo being a renewable resource (it is actually a fast growing grass and not a wood), is the ideal resource for the manufacture of woody boards, sheets, etc. An aside- bamboo is said to sequester more carbon than most woods.
There are a number of manufacturers of such Bamboo Enginnered products in the country, but there are differences in quality. (incidentally, there are is a Bamboo Mat Corrugated Sheet, BMCS, alternative to corrugated tin sheets.

A non-toxic anti-termite method

Sustainability or not, whether we withdraw water from the ground of not, the usage of any toxic substance for any activity is a strict NO. Anti-termite solutions are injected in great amounts into and around the excavation works during the start of construction, and we were concerned about such mindless injection of toxins into the soil. An alternative neem-based solution that we had been using for many years was employed to overcome this. The application method is pretty much the same,.. the difference being that the vendor who promoted this product would readily take a swig of this solution to drive home the point that it was harmless to humans, and not a poison.

Apart from these main interventions, there were many other significant but often overlooked options that were put in use in the construction of this building. For example-

• the usage of quarry dust instead of sand in plastering, mortar and concrete..... which is mostly dredged (illegally) from riverine systems
• the architects designed an attractive masonry railing, which used thinner GGBS blocks between bands of kadappa (a slate) and bethamchella (a smooth limestone).... reducing the usage of steel.
• the architects, along with the structural consultant, designed an interesting box trench foundation, specially for the black cotton soil of this region. Essentially, it was a lean concrete mix using large stone aggregate that was filled into this trench and allowed to cure. It was simple to execute and saved us many man-days, and did not need any reinforcement.

In parallel, while the mock-up building came up, other works related to the rest of the main project had been initiated. While the usual large scale vendor finalisation and tendering processes unfurled, another interesting story involving bamboo is worth covering.

As part of the campus, the architects had developed an interesting club building. The form was dramatic, with a gently angled roof protruding from two sides and held over slender built-up columns. The span of the building roof was 120ft x 80 ft. This roof was originally designed as a series of steel trusses (curiously designed to have an inverted arc like profile as it's bottom section) supporting a galvalum sheet roofing. There was also an interesting heat management process designed by the incorporation of a 'silver ceil' insulating fabric stretched across below this truss, ensuring that whatever heat is gained by the roof, is not transferred to the large hall below. The architects had designed this interesting mechanism to manage the venting of this roof.

While we could not but be appreciative of this design, we felt that we could try an alternative to those steel trusses. We proposed the use of bamboo trusses, and even roped in a specialised agency, WonderGrass, to back this. It was decided that a prototype of this truss would be developed in full scale and tested. Apart from this the prototype for the roof structures of three utility buildings (housing the barn, cowshed and gassifier) was also proposed. We worked with ABLA and WonderGrass to finalise this truss design and the prototype development was initiated. As a result we have managed to assemble and erect an 80 ft long truss... a testimony to the structural properties of bamboo and an elegant alternative to steel.

The ACC Greens Village is significant as it highlights innovate use of cement, apart from other building materials & systems, in creating a low ecological footprint built environment. It was also a momentous occasion for ACC, having achieved a significant milestone towards its agenda in promoting sustainability. Here's to the rest of the project.
Click here for more pics of the project.

Are current green initaitives only half measures towards sustainability?

Are current green initiatives only half measures towards sustainability.... merely postponing the inevitable?
Essentially all human activity revolves around the extraction of virgin material, energy production/usage and the generation of waste.
Much of today's 'green' activity focusses on the following:

• Material- Here the focus is keeping things as local as possible and to consume only low energy products. 
• Energy- Here the focus is on producing cleaner power and increasing the usage of renewable energy for our power needs. When it comes to engine fuels, the focus is on moving away from fossil fuels and opting for more non-polluting alternatives like bio-fuels. On the demand end these initiatives have resulted in technology that consume less power or fuel to give us the maximum output.
• Waste- Here the focus is on cleaner non-polluting technologies.

These are well meaning methods towards a greener future, but is it enough to become truly sustainable. That begs the question- what is being truly sustainable? I would imagine that it would mean that we consume material in a manner that there is enough left for posterity... for future generations and other species to live quality lives on this earth. It would also mean that we consume energy/fuel in a manner that there is enough to go by for posterity, or, that any residue of our activities does not result in a toxifying of our air, ground or water.

Now, what would be the steps that we would have to take to ensure that we satisfy the above conditions of sustainability? Let us consider the current 'green' measures:
Materials- By consuming local or consuming low energy products would we meet those conditions? I believe that it all depends on the rate of consumption. The stresses are already showing, with a running out of various stones and timber alternatives, or, the astronomical price increases that we have been seeing. It looks to me that to change to a non-consumerist community would be far more challenging (it's kind of an addiction). The answer would be to reach a near net zero virgin resource consumption situation. The focus would therefore have to be on the development of technologies in nearly all fields that see the use of reused or renewable raw materials. Since at IGH we focus on the built environment, the examples would be along the lines of technology to reuse steel without hampering its brittleness (a result of its carbon content), the making of reconstituted concrete/blocks/tiles that bring the use of cement down to zero, low-energy woody materials/ composites, non-toxic resins and polishes, and so on. Does this mean the end of conventional construction? These are the debating points.... whatever it leads to, one thing is for sure... we would need a radical re-think on the business as usual processes.

Energy- The answer is not whether we should use renewable energy or non-fossil fuel energy. What we ought to be focussing on is whether the overall resources that is used in the production of energy can be sustained for ever? Yes, the sun's energy will last us many millennia, but what about the life of technology like PV... they currently have a shelf life of about 15 to 20 years.... what then? Have we figured out methods to manufacture PV technology in a manner that we dont spend more than what we expect the PV products to produce? Can we design systems that are perennial? What about bio-fuels? Can we be sure that we would have enough land for growing the bio-fuel without eating into our forests or adding pressure on our regular food crops?
Waste- Here is quite a crucial component that defines how badly we have tilted the sustainability balance. Be it materials we use for all production/building activity, or, everything we consume as food and other daily consumables, or the fuel we burn to power our transportation, cities and industry..... we leave something behind. Can we endeavour to work on technology that produces no residue, or, renders all such gaseous, liquid or.solid residue into re-usable materials or inert enough not to cause any problem whatsoever to our air, water or land?

The earth's population is slated to settle around the 10 billion mark. While it means that there would only be that many mouths to feed, another phenomenon, which is the increasing global urban population, would have a pronounced impact on what resources we have left. Along with this comes a greater hunger and greater 'want' from a basic 'need' based society. The pressure will be on us to consume less, and pollute less.... which is as much a measure of attitude/s as it is a challenge for technology. Like I mentioned earlier, the former has led us to where we are... and while we do our utmost to bring change in lifestyles, the focus would equally be on gearing the latter to meet the stringent sustainability demands as mentioned above.

I do agree that current 'green'measures are probably the first steps towards such a change, but it only seems prudent that we know where we are headed and what, at best, will suffice.

Tenets of Sustainable Living

Perhaps we need a sustainability version !!

If we had to define what would constitute the basic principles when it comes to reducing your ecological footprint what would they be?. Here is one version:

• Consume less
• Power
• Water
• Building/construction materials- go simple tech as against high-tech
• Consumer goods
• Consume local
• Eat local produce
• Build using local materials and skills
• Generate less waste.... Re-use and recycle
• Build using old or discarded materials... apply clean tech
• Compost and share with neighbours
• Choose what you buy.... things that wont contribute to the waste you produce
• Throw away less
• Occupy less space
• Do you really need all that extra built area?
• Do you really need that big a car?
• Go independent... as far as possible
• Build as much with what you have
• Be self sufficient in your harvesting water and generation of energy (as long as it makes sense in terms of the Life-cycle)
• Manage what little waste that you generate
• Travel less and travel green
• Use your car/two-wheeler less frequently
• Use a bus instead of your car/bike.
• Use a cycle for the short distances
• And if you can walk... go for it.
• Work as a community
• Share resources
• Share travel resources
• Assist in solving each other's problems
• Get others to live sustainability, it is your responsibility too
• Give back
• Recharge the ground water
• Share power that you generate
• Plant as many trees as you possibly can
• Take only what you need... probably the most important since it is this very appetite that has gotten us into this environmental glut