To purchase Earth Nurture Additive, or to have technical questions about ENA answered,
please contact Tim Dunn
ENA 2.0 third party laboratory biodegradation test results per ASTM D5338
Sales Office for Europe
Phone: (360) 654-4417
Skype: Earthnurture
17604-11th. Ave. N.E.
Arlington, WA, 98223
USA
in accordance with
ASTM standards
Earth Nurture Europe
Welcome to Earth Nurture's Business-to-Business Website
At Earth Nurture, we are dedicated to seeing that more and more of the plastic disposable items we use every day rejoin the cycle of life. We sell Earth Nurture masterbatch additive for rendering conventional plastics biodegradable in landfills and in natural bodies of water.
Earth Nurture masterbatch additives cause conventional plastics to biodegrade into humus, water and biogas when disposed of in landfills, due to the action of naturally occurring soil micro-organisms. These microorganisms are the same as those which turn dead plant life into humus, the organic part of soil. The result is a looser and lighter soil which can hold more air and moisture, making a better environment for plant life.
Earth Nurture has a masterbatch additive for every common plastic, and many uncommon ones. Earth Nurture has a masterbatch additive that will cause the biodegradation in landfills of: Polypropylene (PP,) Polyethylene (PE,) Low Density Polyethylene (LDPE,) High Density Polyethylene (HDPE,) PET ( Polyethylene terephthalate ,) Polystyrene (PS,) Expanded Polystyrene (EPS, sometimes called Styrofoam, which is a trademarked brand of EPS,) Nylon, and even Polylactic Acid (PLA.)
(A masterbatch additive is an additive which is added to the masterbatch, which is the plastic as it is being melted for final fabrication into sheets or molded products.)
Biodegradable Plastic Technologies Available - A comparison
Table Demonstrating Aerobic Biodegradation of ENA-Treated LDPE Sample
The History of Biodegradable Plastics
Because there are a number of different approaches to biodegrading plastic, and because people have developed so many misconceptions about biodegradable plastics, I have written a brief history of biodegradable plastics. There have been three generations of biodegradable plastic. The first was starch based plastic, PLA, almost always made out of corn. The second generation was oxo-biodegradable conventional plastic, and the third, the current generation, is microbiodegradable conventional plastic.
PLA, or corn-based biodegradable plastic
PLA, or corn-based biodegradable plastic, was said to be the first generation of biodegradable plastic, even though its primary manufacturer, Naturworks, states that it will not biodegrade in any natural environment, nor in landfills. PLA, Poly Lactic Acid, biodegrades only in commercial compost facilities - and many commercial compost facilities refuse to accept PLA. It is made and promoted by corporate giants that have huge financial and political power, such as Cargill, Inc., but it has many drawbacks.
It is billed as ***'sustainable,' as it is based on food sources, primarily corn. However, if all of the disposable plastic products in the world were made out of corn, 238,500,000 tons of corn would be used to make plastic. Prices for corn would rise dramatically, and third world hunger would increase even more dramatically. There are currently 1,000,000,000 hungry people in the third world, says the UN. If the amount of plastic disposables, such as packaging and drinking cups from fast food stands used in the US each year were all made of corn, it would take 18% of the country's farm land to fill the need. That is enough food to feed over 600 million people, people who need that food desperately. If we imagine their condition worsening only slightly, the result could only be a humanitarian catastrophe of appalling proportions. That is the real ramification of 'sustainability' in today's world.
Furthermore, PLA isn't a very good plastic. It imparts an off taste to water when used for water bottles, it melts when used as soup spoons, it's weak, and therefore items made of it are heavy, and it has a short shelf life, sometimes becoming a sticky mess while still in the warehouse. What's more, no recyclers accept it for recycling except the company that manufactures it, which ships it across the US to its one recycling center. In fact, recyclers that don't manufacture PLA, dislike PLA and are trying to ban it, because it gets confused with more conventional plastics, and ruins their recycled plastic batches.
Even the few commercial composters which accept PLA products have a limited appetite for PLA, because it adversely affects the compost batch as too much PLA makes the compost too acidic. One bottle manufacturer did a survey of commercial composters and found that 90% of those surveyed would not accept PLA bottles. Furthermore, PLA cannot be composted by home composters - PLA requires elevated heat beyond what home compost processes generates to compost. The most peculiar thing about calling PLA compostable, is that it leaves no residue in compost, and so it gives no contribution to humus. The ASTM standard for compostable plastic, ASTM D6400, actually requires that compostable plastic makes no contribution to humus. (For information about the effect of the corn boom on the environment, click here.)
Oxo - Biodegradable Plastic, the Second Generation of Biodegradable Plastic
The second generation plastic oxo - biodegradable plastic was very different than the the previous generation of biodegradable plastic called PLA, starch-based plastic, or 'spudware. Oxo-biodegradable plastic had many advantages over PLA-It was invulnerable to water, one might adjust it to the desired biodegradation rate, some products could contain recycled content, it could be recycled, it didn't diminish the grain supply, it was stronger, less expensive, and was made from an otherwise useless industrial byproduct, light naphtha. (Light naphtha is a highly volatile faction of crude oil that cannot be made into gasoline, diesel, fuel oil, or jet fuel.**)
This second-generation biodegradable plastic is little known in the US, but is is well established and widely used in Europe. Tesco and Carrefours, the largest grocery chains in the world, and in France, respectively, package their customers' groceries in oxo-biodegradable 't-shirt' bags. In fact, the largest bakers in Mexico and South Africa package bread in oxo - biodegradable bags, and oxo - biodegradable plastic is becoming common in India and China. The US is so far behind the curve on this, that it is a little embarrassing. (Update: Tesco has stopped using biodegradable plastic shopping bags, citing a study by DEFRA which reflected all of the issues I have cited.) Read the DEFRA report by clicking here.
Oxo - biodegradable plastic doesn't biodegrade when deeply buried in landfills*, because it requires an initial phase of degeneration which required certain environmental factors-oxygen and one of the following three circumstances-heat, UV light, or mechanical stress-and because the subsequent biodegredation part of the degredation only works in oxygenated environments. These circumstances don't exist when deeply buried in landfills, so oxo-biodegradable plastics don't have any benefit for products deeply buried in landfills. Oxo - biodegradable products may, however, offer a benefit if litter is the primary concern, as they degrade in the presence of UV light.
There is a potential problem with UV initiated degradation, however - if it becomes common and products made with oxo-biodegradable additives enter the recycling stream in large numbers, the resulting plastic could have a short lifespan if placed in sunlight. This would be a big problem for items made with recycled plastic such as plastic tarps.
The Third Generation of Biodegradable Conventional Plastics,
which are used in our products: Micro - biodegradable Plastic
There is now a third generation biodegradable plastic product which is the standard plastic we use daily, light naphtha based plastic, with a masterbatch additive (ENA or Earth Nurture Additive,) that will cause it to biodegrade without the need of heat, UV light, mechanical stress, or oxygen. This third-generation plastic is called micro - biodegradable plastic, and it biodegrades when placed into the ground due to the action of micro-organisms naturally occurring in soil.
We now have ENA 2.0 masterbatch additive formulas for biodegrading all common plastics - Polypropylene, Polyethylene, HDPE, LDPE, LLDPE, Polystyrene, Expanded Polystyrene, Nylon, and many others, including PLA. Products made with our ENA 2.0 additives are recyclable, invulnerable to water, don't diminish the grain supply, and are much less expensive than bioplastics. Products made with our additives also have the advantage of having the same shelf life as regular plastics, unlike PLA and oxo - biodegradable plastic, as it does not biodegrade until it is in the presence of soil micro-organisms.
Additionally, this new ENA micro - biodegradable plastic will definitely biodegrade when buried in the ground in either aerobic or anaerobic environments, ie. in a land fill.
With this new generation of ENA micro - biodegradable plastic, biodegradation is delayed long enough that there is time to cap the landfills, (Click to see a video about using methane from landfills,) so the methane is burned off or even used to generate electricity, as is being done in almost 500 US land fills currently. Like all of our products, this new biodegradable plastic is recyclable and completely non-toxic to people, plants, and animals, and is made of ingredients approved by the FDA for food contact.
In our view, by using naphtha-based ENA micro - biodegradable plastic, we are following in the footsteps of the native Americans of the Great Plains, who used every part of the buffalo, the chief resource in their environment. We take an industrial byproduct that used to be wasted and turn it into useful packaging materials and other disposable items. Then the disposable items are turned into humus, to the benefit of the soil and the plants it nurtures. Waste gasses from the conversion process are then used to make electricity. We thus have progressed from wasting an asset to generating three benefits from it for people and our planet.
Update: PET, the clear plastic used in soda and water bottles, is being made partly out of materials of plant origin by the largest bottlers, and Nestle has decided that PLA (corn plastic, or polylactic acid,) is not practical for widespread packaging use. Click here to read about Nestle's use of plant-based PET components. So, in response to the public demand for 'sustainability,' industry is starting to supply "conventional" plastics with at least partly plant-based materials. Read about Coca-Cola's green bottle by clicking here.
Documentation
Please e-mail Tim Dunn for any inquiries, including documentation of any claim made on this website. We have extensive documentation of third party testing of the biodegradability, acceptability for food contact, and environmental harmlessness of our products.
Europe
Earth Nurture does business in Europe as Earth Nurture Europe. To view our European website, click here.
Micro - biodegradability Links
A Canadian high school student has proven that a bacteria, Sphingomonas, eats plastic very quickly, if given a little encouragement.
Click here to read the story.
A Japanese study found that styrene and polystyrene were biodegraded by strains of bacteria. See: "Pseudomonas sp. and Bacillus sp. for styrene decomposition, and Xanthomonas sp. and Sphingobacterium sp. for polystyrene decomposition. Especially, Bacillus sp. STR-Y-O strain decomposed both styrene and polystyrene. Styrene and polystyrene were reduced 40% (9g) and 56% (34g) of initial concentrations (quantity), respectively, in 8 days by strain STR-Y-O."
Every day more studies are done which find that bacteria and fungi exist which will eat plastic. Here is a report about Xylaria and Trichoderma fungi biodegrading plastic.
Miscellaneous Links
A very large and highly technical study about the environmental benefits of conventional plastic garbage bags versus bioplastic garbage bags (PLA, aka corn-plastic,) bags has just been released. Conventional plastic was found to be more environmentally friendly in all categories, including non-renewable energy use, global warming impact, and pollution. (The study is no longer on line.) Click here for an overview of the subject.
Bagasse (sugar cane) residue is a compostable product made out of an agricultural byproduct. So far, so good. Is it suitable for making plates, lunch trays, bowls, and other food service ware out of? This chef puts it to the test.
We supply biodegradable bottle preforms for making PET bottles for products such as bottled water. What's a bottle preform? Youtube will show you. Please click here. -And to see what happens inside of a bottle mold, click here.
Footnotes
**It is often implied, quite mistakenly, that a barrel of oil could easily be turned into whatever product is desired. Nothing could be further from the truth. A barrel of crude oil has many complex chemicals in it, of various different weights / densities. These various densities are suitable for producing only a limited number of items. 'Light' naphtha, the kind used to make plastics, is lighter than gasoline, and more dense than natural gas. It has very few uses besides making plastics. It is also used for making products in relatively limited demand, such as 'white gasoline' aka 'Coleman fuel,' lighter fluid, and solvent. Click here to see this illustrated.
***How 'sustainable' is corn? Every phase of cultivation: Planting, fertilization, weed killing, pest killing, harvesting, and transporting of harvested corn, uses diesel to run the machinery which does this work, and the fertilizer used in growing corn is also made out of petroleum. Furthermore, the process uses vast amounts of water, and pollutes the remaining ground water with pesticides and herbicides, rendering it toxic. Click here to read a Time Magazine article which expresses extreme skepticism about the greenness of biofuel. What is the effect of the combination of open markets in world trade and alternative uses for grain, such as gasohol, biodiesel, and 'sustainable plastic? Read this to learn more: Click here to learn more.
How green is composting? Here's one man's calculations. Composting issues
How green are bioplastics compared to plastics made from petroleum products? Click here to see a recent study from the University of Pittsburgh
There are 280 million (American) tons of plastic (255 million metric tonnes) made every year. Worldwide production of PLA, or corn plastic, is about 500,000 tons, or about 2 tenths of one percent of the 'conventional' plastic made every year. It takes about 2.61 tonnes of corn to make one tonne of PLA, so it would take 665 million tonnes of grain to replace all of the conventional plastic with PLA. The UN says that well over a billion people are hungry right now, with a world grain production of 1.73 billion tonnes of grain. It would take 38% of the world's grain supply to make all of the world's plastic out of grain.
The thing to take away from all of this is that you can't just believe cliches or commercial claims about greenness. The gold rush to greenness has been noticed by giant commercial interests, and the public concern about our environment is being ruthlessly exploited by huge companies who have no real concern for the environment. To know what is best for the environment requires vigorous exploration of the fundamental facts, and some extensive math. There is no valid shortcut to knowing what is 'green,' but science.
Welcome to Earth Nurture's Business-to-Business Website
At Earth Nurture, we are dedicated to seeing that more and more of the plastic disposable items we use every day rejoin the cycle of life. We sell Earth Nurture masterbatch additive for rendering conventional plastics biodegradable in landfills and in natural bodies of water.
Earth Nurture masterbatch additives cause conventional plastics to biodegrade into humus, water and biogas when disposed of in landfills, due to the action of naturally occurring soil micro-organisms. These microorganisms are the same as those which turn dead plant life into humus, the organic part of soil. The result is a looser and lighter soil which can hold more air and moisture, making a better environment for plant life.
Earth Nurture has a masterbatch additive for every common plastic, and many uncommon ones. Earth Nurture has a masterbatch additive that will cause the biodegradation in landfills of: Polypropylene (PP,) Polyethylene (PE,) Low Density Polyethylene (LDPE,) High Density Polyethylene (HDPE,) PET ( Polyethylene terephthalate ,) Polystyrene (PS,) Expanded Polystyrene (EPS, sometimes called Styrofoam, which is a trademarked brand of EPS,) Nylon, and even Polylactic Acid (PLA.) (A masterbatch additive is an additive which is added to the masterbatch, which is the plastic as it is being melted for final fabrication into sheets or molded products.)
The History of Biodegradable Plastics
Because there are a number of different approaches to biodegrading plastic, and because people have developed so many misconceptions about biodegradable plastics, I have written a brief history of biodegradable plastics. There have been three generations of biodegradable plastic. The first was starch based plastic, PLA, almost always made out of corn. The second generation was oxo-biodegradable conventional plastic, and the third, the current generation, is microbiodegradable conventional plastic.
PLA, or corn-based biodegradable plastic
PLA, or corn-based biodegradable plastic, was said to be the first generation of biodegradable plastic, even though its primary manufacturer, Naturworks, states that it will not biodegrade in any natural environment, nor in landfills. PLA, Poly Lactic Acid, biodegrades only in commercial compost facilities - and many commercial compost facilities refuse to accept PLA. It is made and promoted by corporate giants that have huge financial and political power, such as Cargill, Inc., but it has many drawbacks.
It is billed as ***'sustainable,' as it is based on food sources, primarily corn. However, if all of the disposable plastic products in the world were made out of corn, 238,500,000 tons of corn would be used to make plastic. Prices for corn would rise dramatically, and third world hunger would increase even more dramatically. There are currently 1,000,000,000 hungry people in the third world, says the UN. If the amount of plastic disposables, such as packaging and drinking cups from fast food stands used in the US each year were all made of corn, it would take 18% of the country's farm land to fill the need. That is enough food to feed over 600 million people, people who need that food desperately. If we imagine their condition worsening only slightly, the result could only be a humanitarian catastrophe of appalling proportions. That is the real ramification of 'sustainability' in today's world.
Furthermore, PLA isn't a very good plastic. It imparts an off taste to water when used for water bottles, it melts when used as soup spoons, it's weak, and therefore items made of it are heavy, and it has a short shelf life, sometimes becoming a sticky mess while still in the warehouse. What's more, no recyclers accept it for recycling except the company that manufactures it, which ships it across the US to its one recycling center. In fact, recyclers that don't manufacture PLA, dislike PLA and are trying to ban it, because it gets confused with more conventional plastics, and ruins their recycled plastic batches.
Even the few commercial composters which accept PLA products have a limited appetite for PLA, because it adversely affects the compost batch as too much PLA makes the compost too acidic. One bottle manufacturer did a survey of commercial composters and found that 90% of those surveyed would not accept PLA bottles. Furthermore, PLA cannot be composted by home composters - PLA requires elevated heat beyond what home compost processes generates to compost. The most peculiar thing about calling PLA compostable, is that it leaves no residue in compost, and so it gives no contribution to humus. The ASTM standard for compostable plastic, ASTM D6400, actually requires that compostable plastic makes no contribution to humus. (For information about the effect of the corn boom on the environment, click here.)
Oxo - Biodegradable Plastic, the Second Generation of Biodegradable Plastic
The second generation plastic oxo - biodegradable plastic was very different than the the previous generation of biodegradable plastic called PLA, starch-based plastic, or 'spudware. Oxo-biodegradable plastic had many advantages over PLA-It was invulnerable to water, one might adjust it to the desired biodegradation rate, some products could contain recycled content, it could be recycled, it didn't diminish the grain supply, it was stronger, less expensive, and was made from an otherwise useless industrial byproduct, light naphtha. (Light naphtha is a highly volatile faction of crude oil that cannot be made into gasoline, diesel, fuel oil, or jet fuel.**)
This second-generation biodegradable plastic is little known in the US, but is is well established and widely used in Europe. Tesco and Carrefours, the largest grocery chains in the world, and in France, respectively, package their customers' groceries in oxo-biodegradable 't-shirt' bags. In fact, the largest bakers in Mexico and South Africa package bread in oxo - biodegradable bags, and oxo - biodegradable plastic is becoming common in India and China. The US is so far behind the curve on this, that it is a little embarrassing. (Update: Tesco has stopped using biodegradable plastic shopping bags, citing a study by DEFRA which reflected all of the issues I have cited.) Read the DEFRA report by clicking here.
Oxo - biodegradable plastic doesn't biodegrade when deeply buried in landfills*, because it requires an initial phase of degeneration which required certain environmental factors-oxygen and one of the following three circumstances-heat, UV light, or mechanical stress-and because the subsequent biodegredation part of the degredation only works in oxygenated environments. These circumstances don't exist when deeply buried in landfills, so oxo-biodegradable plastics don't have any benefit for products deeply buried in landfills. Oxo - biodegradable products may, however, offer a benefit if litter is the primary concern, as they degrade in the presence of UV light.
There is a potential problem with UV initiated degradation, however - if it becomes common and products made with oxo-biodegradable additives enter the recycling stream in large numbers, the resulting plastic could have a short lifespan if placed in sunlight. This would be a big problem for items made with recycled plastic such as plastic tarps.
The Third Generation of Biodegradable Conventional Plastics,
which are used in our products: Micro - biodegradable Plastic
There is now a third generation biodegradable plastic product which is the standard plastic we use daily, light naphtha based plastic, with a masterbatch additive (ENA or Earth Nurture Additive,) that will cause it to biodegrade without the need of heat, UV light, mechanical stress, or oxygen. This third-generation plastic is called micro - biodegradable plastic, and it biodegrades when placed into the ground due to the action of micro-organisms naturally occurring in soil.
We now have ENA 2.0 masterbatch additive formulas for biodegrading all common plastics - Polypropylene, Polyethylene, HDPE, LDPE, LLDPE, Polystyrene, Expanded Polystyrene, Nylon, and many others, including PLA. Products made with our ENA 2.0 additives are recyclable, invulnerable to water, don't diminish the grain supply, and are much less expensive than bioplastics. Products made with our additives also have the advantage of having the same shelf life as regular plastics, unlike PLA and oxo - biodegradable plastic, as it does not biodegrade until it is in the presence of soil micro-organisms.
Additionally, this new ENA micro - biodegradable plastic will definitely biodegrade when buried in the ground in either aerobic or anaerobic environments, ie. in a land fill.
With this new generation of ENA micro - biodegradable plastic, biodegradation is delayed long enough that there is time to cap the landfills, (Click to see a video about using methane from landfills,) so the methane is burned off or even used to generate electricity, as is being done in almost 500 US land fills currently. Like all of our products, this new biodegradable plastic is recyclable and completely non-toxic to people, plants, and animals, and is made of ingredients approved by the FDA for food contact.
In our view, by using naphtha-based ENA micro - biodegradable plastic, we are following in the footsteps of the native Americans of the Great Plains, who used every part of the buffalo, the chief resource in their environment. We take an industrial byproduct that used to be wasted and turn it into useful packaging materials and other disposable items. Then the disposable items are turned into humus, to the benefit of the soil and the plants it nurtures. Waste gasses from the conversion process are then used to make electricity. We thus have progressed from wasting an asset to generating three benefits from it for people and our planet.
Update: PET, the clear plastic used in soda and water bottles, is being made partly out of materials of plant origin by the largest bottlers, and Nestle has decided that PLA (corn plastic, or polylactic acid,) is not practical for widespread packaging use. Click here to read about Nestle's use of plant-based PET components. So, in response to the public demand for 'sustainability,' industry is starting to supply "conventional" plastics with at least partly plant-based materials. Read about Coca-Cola's green bottle by clicking here.
Documentation
Earth Nurture does business in Europe as Earth Nurture Europe. To view our European website, click here.
A Canadian high school student has proven that a bacteria, Sphingomonas, eats plastic very quickly, if given a little encouragement. Click here to read the story.
A Japanese study found that styrene and polystyrene were biodegraded by strains of bacteria. See: "Pseudomonas sp. and Bacillus sp. for styrene decomposition, and Xanthomonas sp. and Sphingobacterium sp. for polystyrene decomposition. Especially, Bacillus sp. STR-Y-O strain decomposed both styrene and polystyrene. Styrene and polystyrene were reduced 40% (9g) and 56% (34g) of initial concentrations (quantity), respectively, in 8 days by strain STR-Y-O."
Every day more studies are done which find that bacteria and fungi exist which will eat plastic. Here is a report about Xylaria and Trichoderma fungi biodegrading plastic.
A very large and highly technical study about the environmental benefits of conventional plastic garbage bags versus bioplastic garbage bags (PLA, aka corn-plastic,) bags has just been released. Conventional plastic was found to be more environmentally friendly in all categories, including non-renewable energy use, global warming impact, and pollution. (The study is no longer on line.) Click here for an overview of the subject.
Bagasse (sugar cane) residue is a compostable product made out of an agricultural byproduct. So far, so good. Is it suitable for making plates, lunch trays, bowls, and other food service ware out of? This chef puts it to the test.
We supply biodegradable bottle preforms for making PET bottles for products such as bottled water. What's a bottle preform? Youtube will show you. Please click here. -And to see what happens inside of a bottle mold, click here.
Footnotes
**It is often implied, quite mistakenly, that a barrel of oil could easily be turned into whatever product is desired. Nothing could be further from the truth. A barrel of crude oil has many complex chemicals in it, of various different weights / densities. These various densities are suitable for producing only a limited number of items. 'Light' naphtha, the kind used to make plastics, is lighter than gasoline, and more dense than natural gas. It has very few uses besides making plastics. It is also used for making products in relatively limited demand, such as 'white gasoline' aka 'Coleman fuel,' lighter fluid, and solvent. Click here to see this illustrated.
***How 'sustainable' is corn? Every phase of cultivation: Planting, fertilization, weed killing, pest killing, harvesting, and transporting of harvested corn, uses diesel to run the machinery which does this work, and the fertilizer used in growing corn is also made out of petroleum. Furthermore, the process uses vast amounts of water, and pollutes the remaining ground water with pesticides and herbicides, rendering it toxic. Click here to read a Time Magazine article which expresses extreme skepticism about the greenness of biofuel. What is the effect of the combination of open markets in world trade and alternative uses for grain, such as gasohol, biodiesel, and 'sustainable plastic? Read this to learn more: Click here to learn more.
How green is composting? Here's one man's calculations. Composting issues
How green are bioplastics compared to plastics made from petroleum products? Click here to see a recent study from the University of Pittsburgh
There are 280 million (American) tons of plastic (255 million metric tonnes) made every year. Worldwide production of PLA, or corn plastic, is about 500,000 tons, or about 2 tenths of one percent of the 'conventional' plastic made every year. It takes about 2.61 tonnes of corn to make one tonne of PLA, so it would take 665 million tonnes of grain to replace all of the conventional plastic with PLA. The UN says that well over a billion people are hungry right now, with a world grain production of 1.73 billion tonnes of grain. It would take 38% of the world's grain supply to make all of the world's plastic out of grain.
The thing to take away from all of this is that you can't just believe cliches or commercial claims about greenness. The gold rush to greenness has been noticed by giant commercial interests, and the public concern about our environment is being ruthlessly exploited by huge companies who have no real concern for the environment. To know what is best for the environment requires vigorous exploration of the fundamental facts, and some extensive math. There is no valid shortcut to knowing what is 'green,' but science.