Download fact sheet 1 - New Zealand Agricultural Greenhouse Gas

NZAGRC FACTSHEET 1
The Impact of Livestock
Agriculture
onof
Climate
Change
The Impact
Livestock
Agriculture on Climate Change
Agriculture is part of a complex social, economic and environmental global dynamic system. It feeds
more than seven billion people, and underpins economic development and poverty alleviation over much
of the world. It is a major source of greenhouse gases, yet stands to be impacted – both directly and
indirectly – by climate change itself. With a growing global population to feed, it is vital that agricultural
production grows but not its environmental impacts.
There is robust scientific evidence that the climate is changing, and that most of the warming observed over the past
50 years is due to increasing greenhouse gas concentrations from human activities. This fact sheet summarises why,
and how, livestock agriculture contributes to climate change, and why limiting the projected global increase in those
emissions is seen as a key component of dealing with climate change.
The Intergovernmental Panel on Climate
Change (IPCC) estimates that, as at 2005,
agricultural emissions of methane (CH4)
and nitrous oxide (N2O) were responsible
for around 12 per cent of all anthropogenic
(human-sourced) greenhouse gas emissions1.
The livestock sector contributes between
25 and 40 per cent of all anthropogenic
methane emissions – the biggest single
source. Most of that comes from the
stomachs of ruminant animals, where
bacteria break down cellulose in the
absence of oxygen; a process called enteric
fermentation. Some 10 per cent of livestock
terrestrial animal biomass on the planet
“We need to develop
agriculture that is
‘climate smart’ –
generating more
output without the
accompanying
greenhouse gas
emissions”
1. using 100-year Global Warming Potentials to
compare emissions of different gases
Prof Sir John Beddington, UK government Chief
Scientific Advisor.
methane is produced from anaerobic
manure
storage,
with
still
smaller
emissions from animal manure deposited
directly onto soils by grazing animals.
The United Nations Food and Agriculture
Organisation (FAO) has calculated that
the world’s 1.5 billion cattle and buffalo,
1.8 billion sheep, goats and other small
ruminants, and almost one billion pigs
– together constituting 20 per cent of all
fertiliser use, constituting more than half
“Livestock products
contribute 17 per cent to
kilocalorie consumption
and 33 per cent to
protein consumption
globally, but there
are large differences
between rich and poor
countries.”
of all anthropogenic nitrous oxide.
P.K.Thornton (2010)
– produce almost 100 million tonnes of
methane emissions every year.
Nitrous oxide is emitted directly from
soils when nitrogen-rich livestock urea
and faeces, or nitrogen contained in
synthetic fertilisers, is broken down by soil
bacteria. Almost six million tonnes of N20
are produced annually across the globe
Agriculture also emits carbon dioxide (CO2)
through land clearance, loss of soil carbon,
feed crop production and energy use.
Precise figures depend on the accounting
parameters used, but estimates by the
FAO indicate that these sources of CO2
could account for about nine per cent of all
anthropogenic CO2 emissions, mainly from
land clearance.
through urine from managed livestock and
Contribution from agriculture and individual livestock sources to global greenhouse gas emissions
Residential
and
commercial
buildings,
7.9%
indirect manure
emissions, 0.62
Industry,
19.4%
Transport,
13.1%
fossil fuel use, soil carbon
0.16
losses, 0.04
manure
deposition, 0.84
enteric
fermentation, 1.8
Agriculture,
13.5%
Energy
supply,
25.9%
Forestry,
17.4%
Waste and
wastewater,
2.8%
Estimated contribution of different sectors to global greenhouse gas emissions
related to human activities, for 2005. Emissions from agriculture include loss
of soil carbon, but deforestation is counted under forestry. Source: IPCC, 2007.
manure
management
(nitrous oxide),
0.33
leguminous feed
cropping, 0.2
N fertiliser
indirect fertiliser application, 0.1
emissions, 0.1
manure
management
(methane), 0.37
Estimated direct global emissions from different livestock-related activities, in gigatonnes of
CO2-equivalent. Data from Steinfeld et al., 2006, FAO. Data do not include emissions
of CO2 related to land clearance, estimated at 2.4 Gt CO2-eq.
Page 2
A Growing Appetite
Total meat consumption in the developing
world tripled between 1980 and 2002, to more
than 130 million tonnes. As a burgeoning
global population increasingly demands
protein-rich foods, that consumption is
projected to more than double again, to over
300 million tonnes by 2050.
Based on past trends, that would drive
three-fold increases in nitrogen and animal
manure fertiliser use. As a result, by 2050,
agricultural N2O emissions are projected
to increase by between 30 and 60 per cent,
while livestock expansion is expected to
boost methane emissions by 20 to 60 per
cent.
As a consequence, agricultural emissions
of CH4 and N2O are, and will remain, a
significant part of the global greenhouse
gas inventory, and contribute to the total
warming effect from greenhouse gases.
Trends in meat and dairy product consumption
120
Meat Consumption
(kg per person per year)
Meanwhile, global milk consumption is
tipped to almost double from about 500
million tonnes today to almost 900 million
tonnes in 2050.
100
80
60
40
20
0
Year
Dairy Product Consumption
(Fresh milk equivalent, litres per person per year)
Even in the developed world, with its nearly
static population, meat consumption is
expected to continue to grow from just over
100 million tonnes in 2002 to about 126
million tonnes in 2050.
1970
1980
1990
2000
2030
2050
1970
1980
1990
2000
2030
2050
250
200
150
100
50
0
Year
Sub-Saharan Africa
Transition countries
Latin America and Caribbean
Industrial countries
East Asia
Developing countries
Near East / North Africa
South Asia
Trends in reported and projected consumption per capita of meat (top) and dairy products (bottom), from 1970 to
2050. Meat is expressed in kg carcass weight; dairy products is expressed in fresh milk equivalent, excluding
butter. Source: FAO, 2006.
Page 3
Methane – A window of opportunity
Analysis of air bubbles trapped in ice
sheets tells us that methane is more
abundant now than at any time in the
last 850,000 years. Since the industrial
revolution, global average atmospheric
concentrations have increased by 150 per
cent, from around 700 parts per billion by
volume (ppbv) to 1745 ppbv in 1998.
According to the IPCC, the warming effect
from those increased CH4 concentrations
is responsible for roughly a fifth of the
total warming effect from all human
activities. Collectively, human activities
are thought to be responsible for most of
the global warming already observed over
the past half century. Further increases
in greenhouse gas concentrations are
expected to result in even greater climate
changes over the 21st century, especially
if no action is taken to reduce emissions.
Atmospheric methane concentrations
levelled off between 1996 and 2006,
prompting speculation that emissions
had stopped increasing. However, since
2006, concentrations have risen again,
for reasons which are not immediately
clear. Some studies point to a warming
Arctic starting to release methane stored
naturally in wetlands and permafrost.
Based on projected emission trends
from
human
activities,
global
CH4
concentrations could increase by another
10 to 50 per cent by 2050.
Methane is a much more potent greenhouse
“Collectively, human
activities are thought
to be responsible for
most of the global
warming already
observed over the past
half century”
gas than carbon dioxide, but it is relatively
short-lived in the atmosphere – after 12
years, about 60 per cent of that originally
emitted has disappeared. This means that,
if methane emissions were held constant,
concentrations of CH4 in the atmosphere
would soon flatten out. By contrast, even
if CO2 emissions were somehow stabilised,
atmospheric concentrations would still
continue to increase, because a fraction
of every CO2 emission remains in the
atmosphere for many thousands of years.
Given those differences, it is sometimes
argued that, so long as livestock methane
emissions remain constant, they are
Increases in CH4 concentration since 1000 A.D.
Methane concentration
(parts per billion by volume)
2000
1600
1200
800
400
1000
1200
1400
1600
1800
2000
Year
Methane concentrations from 1000 AD to present. Methane concentrations from 1000 AD to present, with expanded section showing data points since 1978. Data from ice cores
(Etheridge et al., 1998, J. Geophys. Res, 103, 15,979-15,993) and the US National Oceanic and Atmospheric Administration (NOAA Earth System Research Laboratory global air
sampling network.(http://www.esrl.noaa.gov/gmd/).
Page 4
“Not acting to tackle methane emissions would require even
greater and more rapid reductions of other greenhouse gases
to achieve the goal of limiting warming to 2°C”
However, this overlooks a number of
realities. Methane concentrations have
risen significantly since the industrial
revolution, and their increased warming
effect is already contributing to climate
change. Methane concentrations are
expected to continue rising as emissions
from livestock production rapidly increase,
and will continue to add to warming caused
by human activities overall.
Scientific studies, as assessed by the IPCC,
agree that greenhouse gas emissions need
to be reduced significantly overall to meet
the world’s stated aim of constraining
global warming to no more than 2°C.
Not acting to tackle methane emissions
would require even greater and more rapid
reductions of other greenhouse gases
to achieve that goal. Methane’s short
atmospheric life span means that any
emission cuts would reduce its warming
Combined warming effect from increasing CH4, N2O and CO2
concentrations
Warming effect (radiative forcing) from increasing
greenhouse gas concentrations in the atmosphere (W/m2)
not adding to the problem of warming.
Therefore, the reasoning goes, there is no
need for agriculture to reduce its methane
emissions.
3
Carbon dioxide (CO2)
Nitrous oxide (N2O)
Methane (CH4)
2
1
0
1800
1850
1900
1950
2000
Contributions to the total warming effect on the global climate from methane, nitrous oxide and carbon dioxide from
1800 to 2010. Source: emissions from Meinshausen et al., 2011, Climatic Change 109(1-2), 213-241 and climate
model calculations.
effect much more quickly than the
warming effect from CO2.
Livestock are a dominant source of methane
from human activities. Limiting emissions
from livestock, without compromising food
security, is therefore clearly an important
part of any international effort to limit GHG
emissions overall, and their effect on the
climate system. In turn, reducing the rate
and magnitude of climate change would
help strengthen global food security while
easing the risks to farmers’ livelihoods
from changing weather patterns.
Developing solutions and tools to
reduce agricultural emissions, without
compromising food security, is therefore
a key element of climate change strategy,
not just globally, but also for New Zealand
with its large livestock industry. These
solutions may take the form of improved
management and new technologies to
reduce emissions of N2O and CH4, and/or
through efforts to increase the absorption
and storage of CO2 in agricultural soils and
through agroforestry.
Page 5
“New Zealand’s unique
emissions profile for
a developed country –
and the pivotal place
of agriculture in the
national economy –
create an urgent need
to reduce livestock
emissions”
New Zealand – An unusual
developed country
Contributions from different sectors to New Zealand's gross emissions
Waste , 3%
Nearly half of New Zealand’s greenhouse
emissions come from agriculture – 33.7
million tonnes of carbon dioxide equivalent
(Mt CO2-e) in 2010 – and 95 per cent of
those come from the pastoral sector.
Energy, 43%
In 2010, the latest year for which figures
are available, the country’s estimated total
greenhouse gas emissions had increased
by 19.8 per cent above 1990 levels. On the
back of an expanding national dairy herd
and higher nitrogen fertiliser application,
agricultural emissions are estimated to
have increased by almost 10 per cent –
2.89 Mt CO2-e – above the 1990 level of
30.85 Mt CO2-e.
Livestock emissions are growing in
many parts of the world. Therefore,
collaborative international research to
develop sustainable options to reduce
emissions, while improving – or at least
maintaining – animal productivity, are
a key part of New Zealand’s response.
Separate NZAGRC fact sheets will detail
current options and research activities to
develop new technologies and approaches
to reduce greenhouse gas emissions, and
to increase soil carbon storage.
Industrial
Processes, 7%
Solvent
Solventand
and
Other
OtherProduct
Product
Use,
~0%
Use,
0%
Percentage contribution of different sectors to New Zealand’s gross greenhouse gas emissions in 2010. Source: MfE,
2012.
Trends in emissions from different sectors in New Zealand
40,000
GHG emissions in kt CO2-equivalent
New Zealand’s unique emissions profile for
a developed country – and the pivotal place
of agriculture in the national economy –
create an urgent need to reduce livestock
emissions, if the country is to meet the goal
of halving its greenhouse gas emissions
by 2050. The eventual participation of
the agriculture sector in New Zealand's
Emissions Trading Scheme also signals
future economic benefits to farmers
from reducing emissions, but costs if no
action is taken. The Government recently
announced its intent to delay the entry of
agriculture into the scheme.
Agriculture,
47%
35,000
30,000
Energy
25,000
Industrial Processes
20,000
Agriculture
15,000
Waste
10,000
5,000
0
1990
1995
2000
2005
2010
Year
Trends in emissions from different sectors in New Zealand, from 1990 to 2010. Source: MfE, 2012.
Page 6
Further reading
IPCC, 2007: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of
the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK.
IPCC, 2007: Climate Change 2007: Mitigation of Climate Change. Contribution of Working Group III to the Fourth Assessment Report
of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK.
European Commission Joint Research Centre, Netherlands Environmental Assessment Agency, 2012: Emissions Database for
Global Atmospheric Research (EDGAR). European Commission (Website: http://edgar.jrc.ec.europa.eu/index.php).
World Bank, 2009: Minding the Stock: Bringing Public Policy to Bear on Livestock Sector Development. Report No. 44010-GLB. The
World Bank, Washington, DC, 74 pp.
FAO, 2002: World agriculture: towards 2015/2030. Summary report. Food and Agriculture Organisation, Rome, Italy, 97 pp.
Steinfeld, H., et al., 2006: Livestock’s Long Shadow. Environmental issues and options. Food and Agriculture Organisation, Rome,
Italy, 389 pp.
FAO, 2006: World agriculture: towards 2030/2050. Prospects for food, nutrition, agriculture and major commodity groups. Interim
report. Food and Agriculture Organisation, Rome, Italy.
FAO, 2012: The LEAD (Livestock, Environment and Development) Initiative. Food and Agriculture Organisation (Website: http://www.
fao.org/agriculture/lead/en/), Rome, Italy.
Cox, P.M., H.A. Jeffery, 2010: Methane radiative forcing controls the allowable CO2 emissions for climate stabilization. Current
Opinion in Environmental Sustainability 2(5-6), 404-408.
Kemfert, C., W.-P. Schill (2009) An Analysis of Methane Mitigation as a Response to Climate Change. Copenhagen Consensus
Center, Copenhagen Business School, Denmark. pp39.
Moss, R.H., et al., 2010: The next generation of scenarios for climate change research and assessment. Nature 463(7282), 747-756.
Shindell, D., et al., 2012: Simultaneously Mitigating Near-Term Climate Change and Improving Human Health and Food Security.
Science 335(6065), 183-189.
Stehfest, E., et al., 2009: Climate benefits of changing diet. Climatic Change. 95(1), 83-102.
Thornton, P.K., 2010: Livestock production: recent trends, future prospects. Philosophical Transactions of the Royal Society B:
Biological Sciences 365(1554), 2853-2867.
MfE, 2012: New Zealand’s Greenhouse Gas Inventory 1990–2010. Report ME 1095 Submitted to the United Nations Framework
Convention on Climate Change. Ministry for the Environment, Wellington, 408 pp.
Published November 2012
Grasslands Research Centre
Tennent Drive
Private Bag 11008
Palmerston North, 4442
New Zealand
Tel
+64 6 351 8334
Fax +64 6 351 8333
[email protected]
www.nzagrc.org.nz
Page 7