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An Overview of Climate Change

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Possible effects on agriculture and land use : how resilient are we? ... Some benefits from climate change from milder 'average' climate and increased CO2. ... – PowerPoint PPT presentation

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Title: 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.
  • .
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