In order to reduce emissions
of greenhouse gases in the atmosphere it
is necessary to make sure that carbon is
stored on the ground to the greatest extent
possible. But how do you qualify the potential
of landscapes to stock carbon? Researchers
now present the first continental-scale
assessment of which areas may provide the
greatest direct and indirect benefits from
carbon storage reforestation projects in
Africa.
2013.12.18 | CHRISTINA
TROELSEN - It is increasingly recognized
that climate change has the potential to
threaten people and nature, and that it
is imperative to tackle the drivers of climate
change, namely greenhouse gases. One way
to slow climate change is to increase the
number of trees on Earth, as they, through
photosynthesis, take up the greenhouse gas
carbon dioxide, converting it to carbon
products which are stored in the vegetation
(in the form of wood, roots, leaves) and
oxygen.
New forests continue
to accumulate carbon for hundreds of years.
Therefore, forestation projects are one
way of generating ‘carbon credits’, which
are tradable units on the carbon market.
The more carbon is stored in the vegetation,
the more profitable such projects are.
Restoring forests should
bring especially high carbon returns in
areas where plants grow fast and to big
sizes, but where disturbances such as deforestation,
fires, and degradation have resulted in
much of the vegetation being destroyed.
However, little information exists on where
such areas are, and how big their carbon
storage potential is.
Researchers from Aarhus
University, Denmark, the University of Pretoria,
South Africa, and the Council for Scientific
and Industrial Research in South Africa
have now developed a method to calculate
the difference between the potential carbon
that could be stored in vegetation if there
were no disturbances and the carbon that
is currently stored in vegetation in tropical
Africa.
The researchers based
their analysis on a satellite-derived map
of current carbon being stored in vegetation.
Combining it with data on environmental
factors that affect plant growth, such as
climate and soil, they could model the maximum
amount of carbon that could be stored in
vegetation across tropical Africa. By subtracting
the actual amount of carbon currently stored
in vegetation from this, they could thus
show where in Africa carbon-stocking projects
would be particularly profitable.
People and biodiversity
factors are also important
In reality, such a map
of where most carbon could be stored is
probably of limited use, because there may
be a number of constraints to setting up
forestation projects to stock carbon. For
example, in a city with high levels of rainfall
and temperatures it might bring high carbon
returns; however, it would be unlikely to
be profitable as land value in cities is
high, and because it would be problematic
to have to relocate people. Therefore, such
constraints must be considered when planning
carbon forests.
In addition, it might
be a good idea to consider whether there
are wider benefits to setting up such projects.
“We used the map, which
showed where carbon forests would bring
high returns, to ask where carbon-stocking
by forestation would not only be highly
profitable, but where it would also minimize
conflict with people, and benefit biodiversity
and people,” says Michelle Greve from the
University of Pretoria, who led the project
as part of her PhD at Aarhus University.
“Therefore, we applied
a method to optimally select areas which
would not only have high carbon returns,
but would also conserve native biodiversity
and support ecosystem services, that is,
services that the environment provides which
benefit humans. The areas also had to have
low land value and human population density,
so as to reduce conflict with people, and
high levels of governance, because setting
up projects in areas with high levels of
violence and corruption would be too risky
and have too low chances of success,” Michelle
Greve explains.
Michelle Greve and her
colleagues could thus identify areas where
carbon projects would have co-benefits.
An example of an area that showed high carbon
returns, but was less important when these
other factors were considered, was the region
around Lake Victoria in East Africa. The
area currently has little vegetation biomass,
but has an excellent climate for tree growth,
and thus has a high potential for carbon
stocking through forests. However, it does
not support as high biodiversity as some
other areas and, more importantly, it is
also densely populated by people who practise
intensive agriculture in the area. So setting
aside land here to plant carbon forests
would not be optimal.
Rather, regions of the
Upper Guinean rainforests of West Africa,
and the Lower Guinean rainforests which
are situated on the coast of Nigeria and
Cameroon, were identified as having optimum
combinations of high carbon stocking potential,
high co-benefits for wildlife conservation
and humans and high feasibility.
“There is a high need
to reduce the amount of greenhouse gases
in the atmosphere. Our approach exemplifies
how strategies to do this can be targeted
to optimize feasibility and co-benefits
for biodiversity and people,” concludes
Jens-Christian Svenning, professor at Aarhus
University and supervisor on the PhD project.
+ More
SUSTAINABLE FOOD PRODUCTION
UNDER PRESSURE ON SEVERAL FRONTS
Increasing pressure
on existing agricultural land requires more
intelligent production systems and solutions
in order to maintain food production in
a sustainable manner.
2013.12.18 | SØREN
TOBBERUP HANSEN - Food production worldwide
is challenged by rising consumption, stagnating
yields in the fields and inefficient production
methods. But there are several options available
for securing production. This can be done
by a strong reliance on biomass and by using
lowland pastures for livestock fodder.Food
production worldwide is challenged by rising
consumption, stagnating yields in the fields
and inefficient production methods. But
there are several options available for
securing production. This can be done by
a strong reliance on biomass and by using
lowland pastures for livestock fodder.
The human population
is continuing to grow. They consume more
and more food. Vegetables, fruit and other
foods are transported long distances between
countries by ship and truck and contribute
to a growing impact on the climate.
At the same time yields
are stagnating, and in some areas the arable
quality of the soil is drastically impoverished
due to inappropriate agricultural practices;
consequently marginal production areas and
nature conservation areas are subsumed into
agricultural production at the expense of
biodiversity. This is tipping the balance
of sustainability in the wrong direction.
When the talk turns
to securing food for all in a sustainable
manner, thus minimising the impact on the
planet, then it is a complex issue that
scientists have to deal with.
One of those researching
the issues of sustainable food production
is John E. Hermansen, section manager at
the Department of Agroecology at Aarhus
University. The combination of population
growth and increased per capita consumption
of animal products does in his opinion put
a lot of pressure on the environment:
- We see that on a global level meat consumption
is rising fast. Over the past 40 years,
pig production has tripled and chicken production
has increased sevenfold, and total meat
consumption is estimated to increase by
another 40 percent over the next 20 years.
The increased consumption will primarily
take place in the countries outside Europe
and North America due to their increased
purchasing power. Meat requires feed for
the animals and feed production requires
large areas under agricultural cultivation.
It piles on the pressure on terrestrial
resources. So there is good reason to innovate,
both in terms of meat consumption and in
the way production is carried out. In the
western world there is also evidence that
reducing meat consumption is good from a
nutritional point of view.
Beef and chicken in
climate battle
Several scientists have
argued that beef should be dropped in favour
of poultry because the climate impact of
beef production is relatively high due to
the large emissions of harmful greenhouse
gases such as methane and CO2 from cattle.
But the equation is
not that straightforward.
- The choice between
beef and chicken is a very complex problem,
because part of the beef production is based
on grassland in no direct competition with
crops for human consumption, while chickens
to a far greater extent receive grain and
soy products that could be used in food
production.
John E. Hermansen adds
as an aside that there are low-hanging fruits
to be picked by concentrating efforts in
countries with very large beef productions
such as Brazil, where the production form
can be optimised.
- The beef cattle today
in Brazil grow very slowly and are quite
old when they reach slaughter weight. This
is damaging the climate, because cattle
emit large amounts of harmful methane. There
is a large potential in intensifying the
production via management improvements.
This will have a positive impact on the
climate, he observes.
Three threats to sustainable
food production
In his research John
E. Hermansen is particularly concerned with
the carbon footprint of food production,
but he draws a picture of three threats
that compel a discussion of a more sustainable
food production in the future.
- There are three main
challenges: Our increasing food production
contributes to a huge loss of biodiversity
which is far beyond what is acceptable.
There is talk about an extinction of species
that is 1,000 times higher than normal as
a result of our current forms of production.
Moreover, we see a large input of mineral
fertilizers, which also threatens the balance
of the ecosystem, and finally there is global
warming, providing humanity with a major
challenge that we have already felt the
consequences of, warns John E. Hermansen.
He points out that food
production is responsible for between a
third and a half of the damage that nature
is currently suffering. Therefore, it is
vital to keep thinking sustainably at all
stages of the production chain and to optimise
the parts that are currently less efficient.
He maintains a hope
that the future will also be able to provide
humanity with sufficient sustainable food.
Small technological breakthroughs continue
to take place that improve the basis for
sustainable food production. Cultured meat
may here be one of the solutions.
- Cultured meat is definitely
an interesting area that can diminish the
challenges. This area will be interesting
to follow in the future, according to John
E. Hermansen.
But he is particularly
concerned with helping to address the current
problem of demand for arable land, for growing
food in the fields best suited for this
purpose, and to then incorporate and utilise
less productive areas for livestock fodder
production.
- Up to a quarter of the available land
in the world is grassland or other extensive
systems for which yields can be very low.
There is a need to develop production methods
that significantly raise the yields on these
areas. At the same time it would be appropriate
to optimise the use of grassland, for example
for the production of proteins for production
animals. To this end we are starting a huge
research effort into biomass, which I see
as the big eye-opener in the future. There
is a huge potential to grow much more biomass
– for energy, food and fodder. It will have
a major impact on sustainability because
it eases the pressure on soil resources,
and that means that we will not need to
incorporate as many of the existing natural
areas in the production. It is also relevant
to look at new methods for the production
of feed proteins such as microalgae that
in commercial productions only require a
very small area. All these initiatives mean
that the cultivated land can be better used
to make food for humans rather than being
mostly used to feed the animals, says John
E. Hermansen.
Organic or conventional
farming
Sustainability is most
often linked to the organic way of farming
rather than the conventional one, but according
to John E. Hermansen there is no clear winner
in terms of carbon footprint. While conventional
operations produce high yields but require
pesticides, use monocultures and give less
biodiversity, the reverse is true for organic
farming.
- We have conducted
studies that show that for organic and conventional
production methods, the carbon footprint
is roughly the same, is his conclusion.
In addition to technological
advances that continually improve yields
and reduce the overall carbon footprint,
he also identifies agroforestry as a form
of production that is worth focusing on
in relation to sustainability.
- Agroforestry is a
production method where the combination
of trees with other crops and/or livestock
means a better utilisation of the solar
radiation for the production of biomass
on an annual basis while reducing the environmental
impact. Although it initially sounds difficult
to implement, it will be one of the areas
where new intelligent technology can make
a difference, is his assessment.
Climate-friendly Christmas
lunch
At our latitudes the
focus has in recent years turned to food
waste. Initiatives John E. Hermansen strongly
welcomes because they reduce food consumption
generally. An increased focus on high-quality
foods will have the same effect, he believes.
John E. Hermansen also
has some advice for those who would like
to do their bit for the climate at the forthcoming
Christmas parties and Christmas dinners:
- We can help our natural
environment by doing without the rice pudding
since the cultivation of rice actually produces
large emissions of methane, which is a very
harmful greenhouse gas, he says with a twinkle
in his eye.
