An Overview of Climate Change

1
An Overview of Climate Change
Alan Hopkins (GES Consulting) Email
environment.hopkins_at_virgin.net
2
Outline of talk

• Climate change and greenhouse gases evidence of
  recent trends in climate change and anticipated
  future trends.
• Possible effects on agriculture and land use
  how resilient are we?
• Adaptations and possible measures to reduce
  climate change
• Opportunities for UK farms and businesses
• Possible threats and the need to plan ahead

3
Terminology

• Climate change and global warming
• The Greenhouse effect
• Greenhouse gases
• Climate change scenarios
• Adaptations and mitigations

4
Greenhouse gases

• 100-yr GWP Concentrations now and 200 years ago
• CO2 1 374 ppm (280)
• Methane 23 1745 ppb (700)
• Nit. oxide 300 314 ppb (270)
• CFCs 4000 268 ppt (zero)

5
Agricultures contribution to greenhouse gas
emissions in UK

• 1 of carbon dioxide
• 30 of methane (enteric fermentation / manure
  management)
• 60 nitrous oxide (soils and fertilisers).
• 8 direct greenhouse gas emissions in the UK
• UK agriculture part of the problem but is part of
  the solution

6
21st Century climate change in UK ?

• Warmer (1-5oC depending on region) and especially
  in summer and autumn
• Regional differences warming greater in SE than
  NW
• Little change in overall annual rainfall but
  increased frequency of wetter winters and of
  drier summers
• More variability in winds, storms, droughts

7
How resilient are existing cropping systems?

• Warmer, drier summers increased probability of
  drought stress (sugar, potatoes, veg crops)
• Risks of damage from increased storminess (soil
  erosion, standing crops, orchards, glass)
• Wetter winters and storms establishment of
  winter-sown crops and fields ops in general.
• New pests and diseases and earlier attacks.
• Problems for glasshouse controls.
• New crops and varieties risk management (mix
  water supplies maintain soil structure)

8

• How resilient is forage /livestock production to
  climate change ? Adaptations
• Elevated CO2 and temperatures longer growing
  season () heat stress (--)
• Changes in seasonal distribution of rainfall
  (field operations, silage, grazing)
• Increased winter wind speed (buildings, stock)
• Increased risks of extreme events (forward
  planning important) soil, water, feed, shelter,
  shade, standings
• Opportunities more legumes, forage maize, whole
  crop

9
Likely future pressures for farmers to mitigate
impacts of climate change what are the options ?

• Improved management of manures, fertiliser, soil
  and water to conserve water supplies, protect
  soil quality and reduce net gaseous emissions.
• Increase carbon sequestration in soils, grass and
  other farmland vegetation (possibly with future
  carbon emissions trading).
• Renewable energy crops to displace fossil fuels
  and at same time remove GHGs from atmosphere.
• Many low-cost options can be implemented now.

10
Management to mitigate greenhouse gas emissions
CH4

• Reduce emissions from enteric fermentation
  through dietary change, rumen manipulation, or
  systematic changes (active research
  internationally).
• Reduce emissions from manure through better
  management (oxygen supply/ covers) or use manure
  in anaerobic digestion as energy source
  potentially very important in future

11
Management to mitigate greenhouse gas emissions
NO2

• Improving fertilizer efficiency
• Optimizing methods and timing of applications
• NH3-based fertilizers rather than NO3 or use
  nitrification chemical inhibitors
• Increasing the soil aeration improving drainage
  on grazed grassland, and avoiding compaction by
  traffic, tillage and grazing livestock.
• Minimizing the grazing period

12
Management to mitigate greenhouse gas emissions
CO2

• Maintain permanent pasture, and reduced tillage,
  rather than annual cultivations.
• More forage leys in existing arable rotations.
• Increase soil organic matter through additions of
  manure etc.
• Maintain and prevent drying out of peaty soils.
• Reduce farm fuels and other C inputs

13
New farm-scale opportunities?

• UK more resilient than some other areas, so
  global effects on world agriculture could benefit
  UK farmers.
• Some benefits from climate change from milder
  average climate and increased CO2.
• New crops, including biofuels and industrial
  crops, and longer growing season in some areas.
• Legumes to offset artificial N inputs (with
  important cash savings for farmers).
• Potential for Carbon trading for C storage in
  soils
• Reduce methane emissions from livestock manures
  through biodigestion.

14
Conclusions

• Convergence of the food economy and the energy
  economy, plus wider environmental goals ? a need
  for integrated approaches. Global effects on
  world agriculture, and energy security issues
  will benefit UK farmers.
• Potential for increased crop and forage yields
  due to climate warming CO2, especially legumes,
  but regional problems of droughts.
• Uncertainties remain. Consensus that we plan to
  adapt to anticipated change and to mitigate the
  probable causes (GHGs) at the farm scale.
• Plan for uncertainties through more conserved
  feeds and mix of crops and harvest / sowing
  times. Multi-purpose land use.
• .