In a forthcoming article¹ in Trends in Ecology and Evolution, Val Smith and colleagues describe why biofuels produced from algae have many benefits:

• The current production of biodiesel (~2 billion gallons in 2006) is far lower than annual consumption of diesel fuel (44 billion gallons per year).  Simply put, biodiesel crops can’t keep pace with demand.  We would have to grow significantly more biofuel crops, which would affect land use by reducing the acreage of food crops or natural habitats.
• Algae fats (lipids) can serve as the feedstocks for many types of fuels, including aviation fuel, which would be a major benefit because airline travel is a huge part of most people’s carbon footprints. Algae fuels are potentially carbon neutral.  Making air travel carbon neutral would be a game changer.
• Algae grow extremely fast—much faster than terrestrial plants (which are made into biodiesel or ethanol).  They lack anatomical parts like roots, flowers, and woody stems that don’t help plants photosynthesize (making them more productive than plants).
• One of the most amazing statistics in this paper is how much less land it would take to make algae based fuels compared to terrestrial plants because of the increased productivity of algae.  To produce an amount of fuel equivalent to the global demand for oil, we would only need an area of land equivalent to 3-20% of current croplands.  If we were to use biofuel plant crops instead, we would need about 2-8 times the amount of current global cropland. That’s so amazing I did a double take when I read it.
  
• Algae can be grown in tanks on lands that are marginally useful for crops so that we don’t have to sacrifice croplands.
• They can serve double-duty by removing excess nutrients from wastewater, thereby linking energy production and wastewater treatment.
• Algal production virtually eliminates the use of herbicides and insecticides and uses much less water than growing crops for fuels.

They also point out an interesting pitfall:

• Bioreactors containing algae are often unintentionally invaded by zooplankton that eat the algae.  This can lead to predator-prey-type cycles in algae biomass, which is not good when you want to maximize algal biomass production.
• The solution?  Add fish that eat the zooplankton.  This would cause “top-down” pressure on the zooplankton, keeping their populations in check.

¹Smith, V. et al (in press) The ecology of algal biodiesel production. Trends in Ecology and Evolution.

_____

Photo credit:  http://www.flickr.com/photos/sandialabs/ / CC BY-NC-SA 2.0

In this week’s issue of Science, Jerry Melillo and colleagues investigate¹ what kinds of impacts might arise from changing land use to grow more cellulosic biofuel crops.  If you think about it, the switch to biofuels could have a big impact on greenhouse gas emissions—and not in a good way.  For instance, clearing a forest or pastureland to grow a biofuel crop could cause a net release of carbon from the ecosystem, as plant growth changes, biomass is lost, and soil decomposition increases.

Using a model of the world economy coupled to a terrestrial ecosystem model, they considered two cases:

• Case 1:  Natural lands (e.g., forests and pastures) are allowed to be converted to meet increasing biofuel demand.
• Case 2: Existing managed lands are managed even more intensely to generate biofuel demand.

What did they find?

• Both cases generated a global biofuel crop area exceeding the current agricultural area used to produce food.  Not surprisingly, the two cases generated different land use outcomes.  Case 1 led to more loss of forests and pastures than case 2.
• In Case 1, there is a much larger overall loss of carbon from ecosystems caused by land use change.  Less carbon was released in case 2 because of lower deforestation and increased use of pasture/shrubland/savanna—all of which can begin to accumulate carbon in soils when managed for biofuels.
• The loss of nitrogen from fertilizer becomes a larger source of greenhouse gas emissions (as N₂O) than land use change.  Although you might expect more fertilizer use and greater greenhouse gas loss with more intensively in case 2, this wasn’t the case, with both using roughly the same amount.
• Overall, how do biofuels fare?  Case 2 ends up releasing fewer greenhouse gases overall, not surprisingly because there is less land conversion.  However, they found that you need to consider the benefits of biofuel production for a long time period (2009-2100) rather than shorter time (2009-2030) because the large initial carbon releases caused by land use and changes and nitrogen releases from fertilizer actually make using biofuels worse than not using them over the short term.

¹ Melillo, J.M. et al. (2009) Indirect emissions from biofuels: How important? Science 326:1397-1399.

_____

Photo credit:  http://www.flickr.com/photos/gusset/ / CC BY-NC-SA 2.0

Palm oil has garnered a lot of news recently.  It’s an ingredient in many processed foods and, increasingly, is being used to make biodiesel fuel.

One initial concern was the destruction of tropical rainforests and peatlands to create palm oil plantations.  To the extent that these plantations are leading to habitat destruction in places like Indonesia, this threatens species like the orangutan.

In this week’s  early edition of the Proceedings of the National Academy of Sciences (open access), a team addressed a second potential problem:  air pollution, specifically ground-level ozone production.

The news about ozone is potentially confusing, so let me start with a quick primer:

• Ozone’s chemical formula is O₃, which is similar to oxygen we breathe in the air (O₂).
• Ozone is a highly oxidizing molecule, which means that it is harmful to living organisms when it comes in contact with them (such as when we inhale it).  If you have ever been around electrical motors and you smell a pungent odor, that’s ozone.
• Ozone in the stratosphere (upper atmosphere) is good for life on Earth.  It absorbs ultraviolet light and prevents us from getting skin cancer.   This is the ozone that gets damaged by CFCs and other gases, creating the ozone hole over Antarctica.  Because we do not come into contact with this ozone, we benefit from it’s sunscreen properties without suffering any ill health effects.
• Ozone in the troposphere (the part of the atmosphere near the ground, so it’s also called “ground-level” ozone), however, is not a good thing to have around because this is the part of the atmosphere that comes in contact with living organisms.
• Ground-level ozone is often a byproduct of urban sprawl.  It forms when volatile organic carbon (VOC) from vehicles (think gasoline vapor) and vegetation (think the smell of Christmas trees) react with nitric oxides from car exhaust under warm, sunny conditions.
• It’s a part of the chemical soup we call smog.  This is why we often see code orange or code red days in metro suburban areas like Washington DC, suburban NY, Atlanta, and Raleigh-Durham, NC warning people with respiratory illnesses, children, and the elderly to stay inside.
• Although there is reason to believe that increasing ozone is connected with the rising incidence of asthma, that link has not been well established.
• The World Health Organization has recommended exposure limits of no more than 50 parts per billion in any 8 hour period.

The PNAS article indicates that ozone production is a growing threat in palm plantations, which show higher temperatures and levels of VOCs and nitric oxides than adjacent rainforests.

Although the level of ozone in palm plantations is not yet at a level that threatens health, the team used a model of ozone production to suggest that if nitric oxide emissions were to reach levels seen in the developed Western world (which may be expected with further development and auto use), this could lead to ozone concentrations exceeding 100 ppb, which is considered an emergency air quality event.

Bottom line:  In tropical regions, we need to think of how to balance economic development, biofuel production, habitat protection, and–now– human health.   To the extent that processed foods and biofuel production are driven largely by consumption in industrialized countries, we share in the responsibility of dealing with this issue.

Already, some companies like Whole Foods have banned unsustainably produced palm oil to combat habitat destruction, but this doesn’t solve the new issue of air pollution.  The article suggests that new varieties of palm plants that emit much lower amounts of VOCs could solve this problem.  That’s good news.

Photo credit: http://www.flickr.com/photos/ahvega/ / CC BY 2.0

Here’ s the issue:  When we think of using, say, wood from forests or grasses from grasslands for energy, we normally think of this process as being carbon neutral–i.e., the carbon released when we burn the wood/grass will be taken back up by the regenerating forest/grassland.  No net change in atmospheric CO₂.  At face value, this sounds like a great strategy for dealing with atmospheric CO₂.

However, the authors indicate that the carbon accounting system in the Kyoto protocol, EU carbon trading system, and developing U.S. cap and trade plans makes a mistake in how biofuels are handled.  Specifically, because of the carbon neutrality of biofuels, the carbon accounting system simply ignores (1) the release of carbon to the atmosphere from biofuel burning and (2) the movement of carbon from the atmosphere back into regenerating forests and grasslands (or other biofuel crop).  At first glance, this appears to make sense: If burning biofuels is carbon neutral, just ignore the release and uptake of carbon since they cancel one another out.

There are two major problems with this–one ecological and another economic:

Ecological problem:

Let’s say we have a coal-fired power plant that we convert to a wood-burning power plant.  As the authors point out, the switch from coal to biofuels does not cause any less carbon to go up the smokestack.  Thus, we are still contributing carbon to the atmosphere, whether we burn fossil fuels or biofuels.  Over the course of the next several decades, regenerating forests will remove this carbon from the atmosphere.  Therefore, it’s important to note that while we have not added any net carbon to the atmosphere with biofuels, we also have not decreased our carbon emissions.  Thus, it’s easy to get lulled into a sense that we are reducing atmospheric CO₂ by using biofuels, when, in reality, we really are just not making the atmospheric CO₂ rise any worse.

If we want to reduce atmospheric CO₂ using biofuels, we can’t simply burn existing crops or forests and let them regrow.  Remember, that’s just carbon neutral.  Rather, we need to alter land use so that we generate a net sink of carbon somehow–for instance, by converting unproductive lands to productive forests or grasslands that could be used for biofuels. Here’s how:

• Step 1:  First, we reduce atmospheric CO₂ by converting unproductive land to a productive ecosystem with plants that grow better than before (i.e., add more biomass).
• Step 2:  Then, we maintain our energy system at carbon neutrality by harvesting and regrowing the productive trees and grasses over and over.

By adding step 1, we have created a net sink that actually helps reduce emissions.

Economic problem:

Recall the flaw in the carbon accounting system:  It is assumed that because biofuels are carbon neutral, they are omitted from the carbon accounting process altogether.  This sends a strong message that burning biofuels  is a zero emission process. As the authors state,

[T]he clearing of long-established forests to burn wood or to grow energy crops is counted as a 100% reduction in energy emissions despite causing large releases of carbon….When bioenergy from any biomass is counted as carbon neutral, economics favor large-scale land conversion for bioenergy regardless of the actual net emissions

Put another way, when framed as a zero-emission process, biofuels suddenly look very attractive.  It therefore creates strong incentives to make our energy production driven by biofuels.  This, in turn, leads to strong incentives to alter land use for the production of biofuels.

Another study this year in Science showed that when carbon mitigation strategies, such as carbon taxes, are only focused on fossil and industrial emissions, this creates incentives to increase biofuel energy. Why? Because in the existing carbon accounting process, biofuel emissions are not counted and therefore can’t be taxed.

Their models revealed the striking impacts resulting from this incentive:  The economic demand for biofuel crops soars, causing the conversion of almost all natural forests and grasslands to biofuel crops.  Our terrestrial biosphere would basically consist of deserts (15%), tundra (5%), a few managed forests (5%), and biofuels crops (50%) and food crops (25%).  That’s 75% of our land mass in some kind of crop.  The world as we know it would look like Iowa or Kansas!

In contrast, if terrestrial emissions from sources like biofuels were accounted for and taxed, there is no incentive to create a massive shift to biofuels because doing so costs money.  The result is we maintain land cover types much like they are today.

___

Bottom line:  We should account for biofuel energy release of carbon to the atmosphere.  Doing so will remind us that we need to (1) make sure we create net sinks of carbon if we want biofuels to actually reduce atmospheric CO₂ and (2) account for all carbon flows that should be considered in mitigation strategies, thereby preventing perverse incentives to destroy our native forests and grasslands in favor of biofuel production.