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Adapting Livestock Production Systems to Climate Change

15 September 2009

Greenhouse gases such as methane (CH4) and nitrous oxide (N20) are both primarily increased through agricultural practices such as land clearing, soil degradation, fires and ruminants, Chris Stokes, a Systems Ecologist at the CSIRO Sustainable Ecosystems Laboratory in Australia, told the 43rd Nottingham Feed Conference. Charlotte Johnston, TheCattleSite Junior Editor reports.

What effects will climate change have on agriculture?

Livestock production is the world's dominant land use, covering about 45 per cent of the earth's land surface, much of it in harsh and variable environments that are unsuitable for other uses. Climate change could impact the amount and quality of produce, reliability of production and the natural resource base on which agriculture depends. Mr Stokes told the conference that although there will be some direct effects on livestock, the majority of influences will be through changes in plant growth and the timing, quantity and quality of forage available.

Increase of carbon dioxide (CO2) and other greenhouse gases in the atmosphere.

Through constant monitoring of the atmosphere, scientists have been able to show that levels of CO2 have risen sharply over the last decade. Not only are they higher than ever before but current levels are 40 per cent higher than pre-industrial times - this is the biggest increase in the shortest amount of time ever seen. It is estimated that by 2100, CO2 levels will be triple what they were pre-industrial times.

Rising CO2 levels have a major effect on plant growth. Positively, greater resource efficiency will increase plant growth.

Mr Stokes explained that loss of moisture will cause greater CO2 fixation per H2O lost, improving water efficiency. Nitrogen efficiency will improve because although nitrogen levels will not change, current levels will have to match the increase in carbon input.

Global warming

Global warming is the warming of the earth through increased greenhouse gases destroying the ozone layer. Research has shown that the world temperature is rising by 0.2 degrees Celsius per decade. Mr Stokes believed that by 2100, the temperature may have risen by as much as 6.4 degrees Celsius. This is the equivalent of a two degree shift in latitude towards the tropics.

Geographic patterns have shown that the interior of continents and the Northern hemisphere is heating up faster than anywhere else. Mr Stokes said that the effects of greenhouses gases are several decades behind, meaning that even if no greenhouse gases entered the atmosphere from today onwards, global warming would continue for several decades until the effects of that came into place.

Unlike the effects of increased CO2 in the atmosphere the effects of rising temperatures will for the most be negative and offset the positive effects of CO2 on plant growth.

Vegetation will have decreased digestibility as a result of lower nutrient and protein content, forage quality will be substantially poorer. The establishment of crops will likely be difficult with little moisture content and will probably need to be planted earlier or require greater inputs, increasing costs.

As mentioned above there will be a two degree shift in latitude meaning a poleward expansion of tropical vegetation. This, Mr Stokes believed, may be of benefit to some, as it will be possible to grow certain crops where before environmental limitations have prevented.

For livestock there will be greater induced heat stress. Water demand will become vital to the location of livestock systems and has been seen recently with the spread of the bluetongue virus to the UK, a poleward expansion of pests and diseases.

Rainfall

This will have the greatest effect on plant growth, however is the least certain of all effects. A warmer temperature will mean a more intense hydrological cycle, although there would be strong geographical variability. It is likely more rain will fall in the tropics and rainfall will decrease in the mid latitudes.

An increase in rainfall may be helpful in some areas reducing the growing season and demand for irrigation. However changes to rainfall are likely to be irregular varying seasonally. Increased rainfall will intensify soil erosion reducing nutrients in soils, thus reducing effectiveness. Mr Stokes warned that pasture production will respond sensitively to changes in rainfall as growth, cover and run off effecting quantity, quality, seasonal availability and reliability.

Risks and opportunities

There are both risks to mitigate and opportunities to act upon, says Mr Stokes. The earlier industries and governments respond to limiting the problems the less adaption will be required. New opportunities taken as soon as possible will put producers at a better competitive advantage. The impacts of climate change both positive and negative will be strongly modified by the way in which people respond to the challenges.

In the short term, better management by enhancing "best practice" will mitigate effects. This can be undertaken through diet quality and feeding patterns, reducing supplements fed, better grass management resulting in less fertilser needed, changing stocking rates to match pasture production, seasonal forecasting - preparing for what effects increased/ decreased rainfall may have on feed supplies or adjusting herd management to altered seasonal patterns of forage production. Improved herd management will include disease and pest management and monitoring as well as husbandry and welfare. The practices mentioned above provide immediate benefits regardless of climate change.

In the long term, adoption will be the key to success, says Mr Stokes. Vulnerability to climate change can be reduced by preparing, evaluating and implementing adaption strategies that limit the risks of negative impacts whilst taking advantage of new opportunities. Look at new options available and improving what is already in place such as infrastructure, climate ready breeds, varieties of feed which will be better adapted to survive. Industries and governments will need to work together with producers to implement proposed systems and provide support on farms, particularly for those who are first exposed to the risk.

In some areas, effects of climate change may be unavoidable or proposed changes unviable. In these places, other options should be considered such as changing land use. Extra support is required for these transitions to successfully occur.

Policies can be introduced to reduce conflicts taking into account greenhouse gases, drought, water and pollution and encourage development, evaluation and adoption of effective strategies. Mr Stokes told the conference that in Australia, an initiative called 'Natural Resource Management' has identified regions where natural resource management is vital to ensure the communities ongoing social, economic and environmental wellbeing. Regions then identify and coordinate actions that address issues specific to that region.

Conclusion

In order to continue to thrive in the future, livestock industries need to anticipate these changes, be prepared for uncertainty and develop adaption strategies now. Some governments are more active than others in addressing climate change issues. For climate adaption to occur people need to be aware that climate change is real, what the practical impacts will be and how it will effect businesses. Effective communication will demonstrate the benefits of adaption in reducing potential impacts.

Don't be afraid to change farming practices and adapt so as to use the opportunity to its advantage. Although inevitably an aspect of climate adaption will be to accept that uncertainty in unavoidable and that decisions made on imperfect knowledge may turn out to be suboptimal. It is therefore equally important to ensure that legislation and policies reflect such experiences and incorporate this and other new knowledge into improving adaptive responses over time.

September 2009

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