There is no differentiation in the application of agriculture to bio-fuel anywhere in the paper. It is agriculture and fertilizer that is the problem. The distressing oversight is that animal food stocks, which are considerably co-produced with human food stocks and those same human food stocks are not considered. Please see http://www.epa.gov/nitrousoxide/sources.html for more information

Given that any biomass used in co-production is used in food production then the net gain in N2O, even according to this paper must therefore be 0. That is bio-fuels in and of themselves add nothing to the burden of agriculture. It is only the agricultural process that is a problem.

There is a problem, surely. Associating it with Bio-fuels is myopic and borders on irresponsible.

There is NO association with bio-fuels other than the root crop in the original paper. Nitrous oxide is not a result of the burning of fuel.

F. D. Hanisko, Oxford, England

To all the "positiveists" getting on the bio-deisel bandwagon without having done ANY research on the matter, I have this to say. Professor Keith Smith of University of Edinburg in Scotland is one of several ecientists who has revealed that bio-deisel produces at least 296 times the amount of nitrous oxide than standard deisel fuel does. Deisel fuel as it is today produce less emissions at the tailpipe than gas does. Let's get our facts straight before we advocate.

Eric Johnson Toronto Ontario

Eric Johnson, Toronto, Ontario

The emissions the biofuel engines produce is first pulled out of the atmosphere by the plant that are used to manufacture the fuel. That's a lot better than pulling ancient carbon out of the ground and spewing it into the air. With biofuels, the carbon released will be sucked back into the fuel crops and pumped right back into your tank at a later date. They won't contribute to global warming that way.

Warren, Seattle, Wa

Macca points out that a "small" adjustment in engine timing will cool the combustion temps. Possibly correct but cooler combustion means less power, hence, more fuel used to do the same work. More fuel used equals more pollution for the same amount of work. Wake up people, Ethanol and bio-fuel is NOT the answer!

Ogre, Interlochen, MI

Let's hear some innovative problem solving on how we can live WITHOUT the current level of dependence on fossil or ‘bio’ fuels. Use less, gain much. (and GO CATS!)

Judy Cameron, Geelong, Australia

<Let the planet warm and we will adapt! That's evolution! If areas flood, we move; if it gets warmer we shed clothes and Britain grows olives and figs! - Rod Garr, Miami, USA>
And if the weather gets too rough to grow food, we all starve. That is also evolution.

Steve, Kenilworth, UK

The article can be found at

http://www.atmos-chem-phys-discuss.net/7/11191/2007/acpd-7-11191-2007.pdf

It is clearly about emissions caused during the growing phase of the crops, hence there is nothings to clean up using a catalytic converter.

Ulf Winkler, Exeter, UK

The major advantages of bio-diesel fuels is the tremendous reduction in pariculate matter and other pollutants produced compared to petroleum-based fuels. Bio-diesel is naturally an ultra-low sulfur fuel and does not require a de-sulfurization process to remove it from the fuel. De-sulfurization of petroleum-based diesel produces SO2 and/or sulfuric acid as a by-product at the processing facilities that requires handling.

An increase of 50 to 70% of greenhouse gases? I don't buy it. Sounds like the researchers may get grant money from big oil.

Rick, Tucson,

Its not all about greenhouse gases. I think a major benefit to biofuels in the US is its ability to help us be less dependent on foreign oil sources.

Plus, if we can some how package the nitrous oxide, we can sell it to hippies.

Michael, Cincinnati, Ohio

In Brazil,special in Sao Paulo state area, we don't have any kind of slave labour. Your competitive advantages on ethanol production arerelated to climate, weather, good breeding program and a lot of research.

We can provide biofuels to whole world without destruction of any tree in rain forest, because we have millions hectares available to crops

Marcelo Pierossi, Campinas , Brazil

The article is misleading on one point.

Ethanol is not biodiesel, it is alcohol which contains no nitrogen at all. Biodiesel can be made from maise, but in the US at least, it is primarily used to produce ethanol which is then mixed with gasoline and used in gasoline powered vehicles.

Mark, San Francisco,

This is interesting. The scientist has a history of pro-environmental positions related to the ozone layer, so I'd hesitate to lump him in with the oil money scientists. On the other hand, let's wait to see if his research is duplicated. Re the confusion about biofuels and carbon neutrality, they are carbon neutral, but CO2 isn't the only greenhouse gas. Other GHG include methane and N2O. The study says that N2O increases, and everybody agrees that N2O is a much (230-290 times) more potent GHG than CO2. The reason most of the focus is on CO2 for GHG reduction is that it's the most abundant and easist to reduce. Outside of landfill gas recovery, there's not a lot to be done for methane, SF6 is being reduced, there aren't a lot of emissions to reduce. N2O isn't generally considered a major source of the total GHG issue, but it is important enough that this study does deserve some attention.

John, Sacramento, CA

My problem with the article is that it talks about biodiesel and ethanol as if they were the same thing. Nothing was said about how much ethanol contributes to greenhouse gases.

Andy Guevara, San Diego, CA

Let me clear up a small misconception. The NOx does NOT come from the biofuel. Biofuels contain ZERO nitrogen. The NOx comes from the burning of the fuel (any fuel for that matter) in the engine. The AIR intake provides the N2 that forms NOx from the high temperature combustion. Now since all fuels (fossil or otherwise) need AIR to burn, it is virtually impossible to avoid making at least some NOx as a by-product of the fuel combustion. The real problem for biodiesel is that it tends to burn at a higher temperature than regular #2 diesel. This is a good thing because biodiesel makes less CO, particulates and hydrocarbons, but alas more NOx. If you want it to also make less NOx, then you need to make a SMALL adjustment to the timing of the diesel motor so that the combustion is at a lower temperature. And voila, the NOx is virtually gone too. Another solution is is add a small amount of good old H2O to the fuel mix - the engine runs cooler- NOx gone. Others additives also exist.

Macca, Kansas City, USA

I'm not clear whether it is referred 2 all biofuels or only dat of rapeseed. but i think biogas could be a better alternative dan the plant based biofuel as it has an added advantage of waste management.

lakshminarayana udupa, davanagere, india

"On Top gear in 2003 they showed a car that used saltwater as fuel. The car had a built in powerstation that extracted the hydrogen and used that to create electricity."

In spite of the fact that it takes 20 times as much energy to separate hydrogen from seawater than you get back from burning it?

Generally, when someone claims to be able to break the laws of thermodynamics, you can be pretty sure it's a con.

Slappy Joe, Philadelphia,

Can you provide the name of the article and its authors in the Atmospheric Chemistry and Physics Journal and the issue in which it can be found.

Susan, Bellmere, Australia QLD

On Top gear in 2003 they showed a car that used saltwater as fuel. The car had a built in powerstation that extracted the hydrogen and used that to create electricity. It could produce enough electricity to run your house. The only exhaust emision produced was water vapour. This was a 100% clean energy car. IF the government is to tax us so heavily, then why cannot they use the billions of pounds raised to get these cars manufactured more cheaply?

Oh yeah, how are the oil companies goung to be able to charge us so much for seawater? A multi-trillion dollar industry could be shut down almost overnight!

And don't even get me started on zero point!

Ken Hall, Barrow-in-Furness, UK

This sounds awfully dubious.
1. Nitrous oxides (NOX) are more potent as greenhouse gases than CO2 but they eventually break down into the more stable molecules: oxygen and nitrogen. CO2 is already in its most stable form.
2. NOX are also associated with sub-optimum combustion conditions and can be cleaned up with a catalytic converter. Give biofuel engines a couple of years to research and this issue will go away.

Peter Enns, nanaimo, BC, Canada

Leonardo: I'm guessing that the biofuels turn a certain amount of atmospheric oxygen and nitrogen into nitrous oxide, which then stays like that for a bit. So as long as they were in use, there'd be a certain amount of extra nitrous oxide in the atmosphere.

(All kinds of things that people in general might at any point freely choose to increase their use of might cause an increase in greenhouse gasses; and the solution to this problem has got to be something other than the banning and taxing of all kinds of things. The solution has to expect that people will freely release whatever kind of gas they like, and it has to deal with the results, if any, not attempt to micro-manage behaviours.)

_Felix, Nottingham,

Thanks Rod Garr for volunteering the US to double their population by take environmental refugees, I presume thats what he means by "adapting". Most of the replies show that people in the developed world dont really know how dependent we are on others for our survival. We need to abolish our emissions of CO2 and our myriad other forms of pollution by living very diiferently, or we will be forced to live differently by the detached forces of nature. I really dont think most of us know what is going to hit us, or how badly we are prepared for the changes. Me? Im learning to grow food and save water! Our children? I think we owe them an apology!!

colin bannon, plymouth, UK

Um... doesn't the nitrogen cycle put nitrates back into the soil where plants can take it to turn into protein? Perhaps this was funded by Shell, BP, Russia etc.

Ben, York,

J Henry
Very well said. You need to speak to Congress and put the subject in the same forum as you did here, maybe they will listen. Or maybe whoever has the deepest pockets and the loudest voice will drown you out. Very sad to think that the solution is as simple as you state and no one will hear. There is the man who claimed to be able to burn salt water, why haven't we heard anymore from that technology?

Paul, San Diego, Ca.

What about the inedible jatropha plant? The hardy, drought-resistant perennial yields 200-400 gallons of oil per acre, can be grown on marginal land, even wasteland, and seems to prevent and may even reverse desertification. Jatropha is an ideal biodeisel feedstock, compared with soy or rapeseed or canola, which yield 40-70 gallons of oil per acre and palm, which yields over 600 gallons but has terrible environmental consequences.

Waste vegetable oil--recycled cooking oil--also makes sense.
So does algae, which could be grown in greenhouses, hydroponically, and yield thousands--maybe even tens of thousands--of gallons of biodiesel feedstock per year.

As for corn or maize, there is no logic--it is simply a matter of corporate welfare--to subsidizing its use in the production of ethanol. Sugarcane and sugarbeet-based ethanol makes much more sense from environmental and economic points of view.

Ethanol plants also consume huge quantities of water, way more than biodiesel plants.

Jonathan , New York, NY

It is patently and principially wrong to use 'the herb of the field' that the Lord God destined man to eat as food (Genesis 3:18 KJV) as fuel. Biofuels made from maize and other edible biomatter may well become a curse. There are many many other inedible plants that should be used.

Jacob, AVONDALE, Arizona USA

Eduardo Ferreyra from Corumba Brazil is unaware of Ethanol produce in Brazil. Yes the Labour in Brazil is cheap, We all know that, but it does not comes to count anything, because the cost of production of ethanol using mechanical harvester is even cheaper than man labour, PLUS ETHANOL OUT OF SUGAR CANE IS 3 TIMES more productive than maize, plus sugar cane is not subsidized either. Let's start be more proactive than complaining.

juliano, Londrina, Brazil

Brazilian ethanol is cheaper because labor costs, nothing else. Sugar crop fields in most parts of Brazil use an almost “slave labor scheme” where workers are secluded in barracks or special villages and are paid with “credits”, not cash. They are forced to buy their food and supplies from the company’s warehouse at huge prices –or walk tens of miles to the nearest village. They are always in the “red” with the company.

Eduardo Ferreyra, Corumbá, Mato Grosso, Brazil

bio fuel, my golf gtdi has run on recycled chip fat for two whole years, and it'll do 120 + (on the auto bahn. )
Why is RECYCLED VEG OIL never EVER mentioned in these articles.
I support, but don't work for, d and b biofuels.co.uk in Bidford on Avon. Don't panic.
I don't eat at mcdonalds(EVER) I don't eat chips either,but my car does!
Cheers dick, lets try and keep the price under 89p, or 65 A LITRE when you buy in bulk. I do it for the planet.

timothy d hartley, evesham, worcs

Biofuel is another feel good initiative that does nothing but cause more problems and fixes nothing. When I put gas with Ethanol in it in my car my milage drops from 25 mpg to 20 mpg and I have been told that a 20% drop in milage is common. If I have to use 5 gallons of fuel instead of 4 just how is that good for the environment? Not to meantion how my food bill has skyrocketed and all of the rainforests that have been cut down to plant palms for the german biodeisel program!

Eddie Smith, Brick, NJ USA

At this point, I think that biofuels are more important than their small impact on global warming. The biofuels could be burned in clean emitting reactors, however, and produce electricity. Or used to heat homes. We need to quit finding reasons to avert the needed changes in the pursuit of energy independence.

Ron Wagner, Decatur, IL

Sounds like the oil companies got to them.

Ryan Cross, san diego, ca, usa

Perhaps someone can remove the nitrogen from the natural oil. As a chemist I wouldn't have thought that would be difficult especially if the contaminant is fertiliser, simply washing the oil with water will dissove the fertiliser and produce clean oil.

bob taylor, aberdeen,

Human contribution to the total volume of greenhouse gas in the planet's atmosphere is 0.3% and nothing in any climate model can show that a 0.3% input or lack of input creates a measureable difference in the trend of global temperatures. What is consistently left out of the debate is the fact that water vapor is the biggest component of greenhouse gasses in the atmosphere and we have no control over that gas. However, one could correctly state that burning hydrogen, as some advocate, would reduce greenhouse gasses, but the by-product of burning hydrogen is water vapor, a greenhouse gas. The best way to address the energy consumption versus pollution issue is to mandate use of the cheapest and cleanest possible fuel and let the economics of the marketplace handle the creation and distribution of this fuel. The problem is that cleanest does not create cheapest and given a choice between dirt and surviving, most underdeveloped countries choose surviving if that is all they can afford

J Henry, Tallahassee, FL

Trans-esterfication of rapeseed oil to produce B100 biodiesel that does increase N2O emissions over that of fossil based diesel is unnecessary. Why waste the time and money to transesterfy when virgin rapeseed oil can be used as fuel in burners or, if you use the engine's cooling system to heat it, as a fuel in diesel vehicles with N2O emissions that are lower then fossil fuels?

Michael G., Easthampton, Massachusetts, USA

I thought the good thing about bio-fuels was that is was "neutral", meaning that it did not merely pump out CO2, but that, when the plant was alive, it took out CO2 from the atmosphere, and when you burn it, it releases it back. How can it be that it is worse than fossil fuels?

Leonardo Williams, Brussels, Belgium

What can we use as bio-fuel? Is wood bad?
I burn maize to heat my home? Is that worse than the gas oil I used to use.?
I have bought a car that consumes less diesel per mile.
Should I buy 5 donkeys and junk the car? But what do I do if the donkeys phart? Should I eat the donkeys. But does donkey meat cause you to phart? Once I've eaten the donkeys should I eat spaghetti made from maize flour?
But would that make us all phart? Not terribly social!
Somebody ought to get it all together and tell us what to do!
In Italy where I live, in the old days, the cows lived on the ground floor and the heat from their bodies provided central heating. But I'm willing to bet that they pharted.
One could of course chase around after pharting animals with boxes of matches and set light to their emanations - but would that help in any way?.
Come on you clever beggars - tell us what to do!
Don't tell me Bush was right when he told us not to worry.
Nothing will ever make me believe Bush!

Bob Scott, Lucignano 52046, Italy

Quelle surprise! Biofuels are among the bigger scam foisted on an all too gullible public. What has always been lacking in the greenhouse gas debate is a rigorous evaluation of the greenhouse gas emissions from alternate fuels. Last I checked biofuels are carbon-based, just like fossil fuels. Biodiesel would be close to if not worse than petro-diesel fuel in terms CO2 per KW output. The credit claimed for plant source has always been spurious, especially when the agrculture takes up energy, and often uses forest land. And let's not even get started on cane or corn-based ethanol.
We can not really reduce greenhouse gases without a combination of substantial reduction in energy use and use of solar, wind, tidal and -YES - nuclear power.

Rav9, Warren, NJ

Sugar Cane ethanol from Brazil should be used and the U.S. Congress should reduce the 54 cents per gallon tariff on it. The corn lobby doesn't want competition from cleaner, cheaper ethanol from Brazil.

Darren Crasto, Katy, TX

Why don't the politicians listen to the scientists first? the reason is because they do note generate votes, it is all about lobbying, voters and subsidies which are your taxes, the scenario is, we don't like fossil fuels because they come from the Middle East, those countries cannot be relied upon and the burning of those fuels creates some of the gases that contribute to global warming , they even have terrorists, so there is a two pronged attack on that front, the farmers are not doing too great in the US and Europe, combine this with oil company lobbyists who want to show that they are doing green things as well, they tell the politicians to subsidise the farmers to grow the crops to be used for bio fuels, then the oilygogs tell the politicians they need subsidies to produce the fuel, a far more expensive process , less productive, Sugar produces 27 times more bio fuel . Tell the politicians that they get green votes. Et voilà, a mess. High food costs and food shortages worldwide

Nick, Camberley, UK

I think it's good knews that maize and rapeseed produce more problems than benefits. It's wrong to take the food out of someone's mouth (poor Mexicans who depend on corn are sufferring price hikes for this basic commodity) to fuel our over -consumption. We have to make better use of the renewable energies we have and curb our greed.

alice hudson, quimper, france

Actually the real issue, rather than Hummers in the USA is the growing number of cars getting on the road in China.

When I consider the number of recalls of Chinese manufactured products for lead paint or other health issues, I wonder what pollution controls used.

J Murray
Canada

James, Thunder Bay, Canada

There are 300 million people in the USA. Most of us want a solution to global warming and do not drive big vehicles as Mr. Garr suggests. The answer is elusive and troubling. As a resident of Iowa I can tell you that capitalism is alive and well in the bio-fuels industry and the wind industry. Thankfully Most of us do not think like Rod Garr of Miami. Ten Hummers for every cyclist? naaa. Come to ragbrai Rod.

Patrick Levi, Des Moines, USA/Iowa

old news! extra extra! old news! old news!

this has been known since they first decided upon a standard fuel for internal combustion engines

how stupid the greens are

chauncey birdwell, kelpsburg, usa/ nh

Oh no! We better stop using ethanol because it will cause the polar ice caps on Mars to melt even faster than they are now.....melting at the same rate as the ones here on earth. Or maybe it's all those martians using ethanol based fuel. Or just maybe, maybe it's the sun that is causing the global warming and man has very little or nothing to do with it in the first place. Duh.

Dave, St.Louis , Missouri

What? Green solutions a sham? NOOOOOO!

Chuck , San Diego, US of A / California

If the middle east was more stable Bio-fuels would only be a small portion of any nations fuel mix, but it is full of zealot self interested dictators that try and use what they can to get what they can on a short term. This is not a new problem, the super tankers that exist today only exist because at one point Egypt decided that the west was not going to get oil by using their canals, so adoptions were made. For that matter Christopher Columbus was looking for a way to the far east that avoided the middle east. Ethanol is not the whole answer only part. But it does not surprise me that some one has to spell doom and gloom about the option. After all I think we all know someone personally that is always telling people they are getting it wrong. Not that they have better answers. My feeling is if you have a better answer I am willing to hear it, if not don't bother those of us that are problem solvers. It will be solved, but not by the "greens"

George, Beatrice, Nebraska, USA

It's hard to understand where the nitrious oxide is coming from when one reads the article. Is the nitrous oxide coming from burning the fuel? Or is it coming from the processing of the maize and rapeseed oil? I'm of the opinion that this warming event, which is natural, is much ado about nothing.

Bill, Elmhurst, Illinois, USA

Here we go again!... Come on Oil Industry supporters! Keep picing matters and spltting hairs to continue burning fossil fuels! And turn your costal waters into acid... You just don't listen, isn't it?

Joao Carlos, Rio de Janeiro, Brazil

Rapeseed oil is cooking oil. It is marketed as canola oil in the US.

Leslie, Barlsesville, Ok, USA

Who cares about emissions? Biofuels are all about reducing the oil price and breaking the grip the oil-rich crazies have over the rest of the world.

MDHinton, Sieradz, Poland

Biofuel has to be one of the most ill conceived ideas to ever be implemented in such large scale and supported by our various governments. There is only approximately a 10% net gain in energy by using biofuel. So for such a small net gain we are dramatically increasing our food prices. If climate change is a concern then biofuel is a very bad idea indeed as there is so much fossil fuel used to produce the biofuel. As mentioned earlier only a 10% net gain in energy. I think it is time to re analyze the entire biofuel situation.

Warren Toles, Clearwater Bay, Canada

I am not surprised. Hysteria about global warming is leading us down all sorts of strange policy paths. The OECD August report of biofuel activity is also very damning of this as a policy choice - its will so affect the prize of food that it will lead to more deaths (they say).

Prof. Stephen Murgatroyd, Edmonton, Alberta, Canada

The point of this study is that people should not jump to conclusions, positive or negative, about solutions to global warming. The solutions should be based on rigorous science and not some “feel good” prejudice that because something fits our anthropomorphic aesthetic that everything that comes from plants or is “renewable”, it must be "good".

Michael, Cambridge, USA/MA

So this is news? It's about time. Fact is, biodiesel can not get certified in California as an alternative fuel for one simple reason; it increases NOx emissions. Yet in the eagerness to promote alternative fuels - the "green community" often purposefully overlooks the major drawbacks of these fuels. Ethanol production, for example, is expensive, and requires more diesel fuel consumption for crop production and processing than the amount of fuel it yields in final form. So before you believe what the "greens" say, research the science first, then find out which special interest groups are donating to "green" causes. The same holds true for the climate change proponents. Fact is, these doomsday purveyors are quite artful in lining their pcokets by scaring people to death.

Ralph Lewis, Houston, Texas

Emissions by transport, is that using fossil fuels or bio-fuels? What else do we use fertilzer for? Only corn? Converted fertilizer and emitted from making the ethanol or planting the corn? N20 is that from planting and using the fertilizer. Explain how it is emitted using the corn to make ethanol. If it is in the planting process, then that skews the whole study based on what ALL fertilizer is used for.

Brian, Windom, USA/ MN

Global warming would obviously disrupt our current population and agriculture patterns, but we are capable of adapting. If there is a significant amount of oil in the arctic, as most nations assume, there must have been abundant plant life there at one time and no ice. Why do we think it's the end of civilazation as we know it if the earth returns to that state? The fortune of individual nations will rise and fall if the artic ice melts, but change should be managed, not feared.

Mike, knoxville, Tennessee

We spend so many years in coming to the conclusion that global warming / climate change is having a dramatic effect on
the world and when everyone sits up and takes note we spend the next however long on finding reasons why we shouldn't do anything about it. Big business supports this, particularly the oil companies with their lobbying budgets which are huge. We need to take action not sit about making excuses. Look at what Andrew Milner says about Japan, look at recycling % across Europe. Britain is finding excuse after excuse. Same as everything in Britain these days: let someone else do it, as long as I don't have to change. That's why the country is going down hill so so fast and why so many people are leaving.

Katherine, Begnins,

How about cooking oil? Do you favour Mexican, Chinese or straight fish and chip oil over domestic oil-fired boiler 28-second fuel? Ever seen a plumber driving a petrol-engine van?
Make road fuel expensive enough and you create incentive.
Regular unleaded here in Japan is around 59p a litre and diesel is 20% less than petrol. Eat your hearts out Brits, because the solution's in your own hands.

Andrew Milner, Karuizawa, Nagano

This is becoming a big yawn! If Britain thinks it is going to save the planet with biofuels, or by David Cameron riding around on a bicycle then it is niaive! For every "bike" ridden by a politician in Britain there are 10 new Hummers put on the road inthe USA! Let the planet warm and we will adapt! That's evolution! If areas flood, we move; if it gets warmer we shed clothes and Britain grows olives and figs!

Rod Garr, Miami, USA