Reducing emissions through land use: what does the latest research tell us?

1. Reducing emissions through land use: what does the latest research tell us? Pete Smith Royal Society-Wolfson Professor of Soils & Global Change & Science Director of Scotland’s ClimateXchange, FSB, FRSE Institute of Biological & Environmental Sciences, School of Biological Sciences, University of Aberdeen, Scotland, UK E-mail: pete.smith@abdn.ac.uk

2. UK emissions now and in 2050 Source: UK Committee on Climate Change

3. Options for reducing GHG emissions through land use • Protect existing carbon stores • protect peatland, • protect woodland • Create new, or increase existing carbon stores • plant more trees on mineral soils, • improve soil management to store more carbon • Reduce GHG emissions from agriculture • Better fertilization and management • Improved efficiency (less GHG per unit product) • Bioenergy • Grow plants for energy – displace fossil fuels

4. Protect and enhance existing carbon stores

5. Peatlands – the UK’s biggest Carbon store UK soils: 9838 ± 2463 Mt C in soils (compare to 114 Mt C in vegetation; Dawson & Smith, 2009; Bradley et al., 2005) Of this, nearly ½ is held in Scottish peatlands, but other important peatlands throughout the UK (Bradley et al., 2005) Bradley et al. (2005)

6. Importance of peatlands in UK • 2007 UK GHG emissions: 635 Mt CO2-eq. ⁄ yr = 170 Mt C / yr (CCC, 2010) • UK LULUCF emissions: -2 Mt CO2-eq. ⁄ yr = 170 Mt C / yr in 2005 = 0.5 Mt C / yr (Dyson et al., 2009) • To 1m, UK peats contain: 1357 Mt C (Bradley et al., 2005) • So loss of 12% of UK peatland C = total annual UK human GHG emissions • Or loss of 0.04% of UK peatland C would wipe out the current UK LULUCF sink Joosten et al. (2011)

7. Effects of agricultural management on organic soils * Depends on water status1Depends on intensity

8. Management guidelines for forestry

9. Reduce emissions from agriculture

10. Agricultural GHG emissions

11. There is significant mitigation potential at low cost in all sectors IPCC, AR4, WGIII (2007)

12. GHG emissions from feasible land use change in GB Smith et al. (2010) Historical best case Recent best case 10% grassland plough-out 5% grassland plough-out 20% grassland plough-out

13. GHG mitigation potential in GB Agronomy Nutrient management Tillage / residue management Agro-forestry 10% > set-aside Grazing land management Fitton et al. (2011)

14. GHG mitigation potential in GB Fitton et al. (2011)

15. GHG mitigation potential in the UK McLeod et al. (2010)

16. Use bioenergy to displace fossil fuels

17. 1 1 1 4 4 3 3 3 3 3 3 Pre-harvest GHG balance of energy crops GHG cost 2 GHG benefit Don’t replace woodlands with any energy crop 1 Also, don’t replace grasslands with OSR 2 SRC & Miscanthus on grassland and arable okay 3 OSR on arable food crop land ~neutral 4 St Clair et al 2008

18. Conclusions / policy implications • Protect existing carbon stocks in peatlands and woodlands • Restore degraded peatlands and plant more trees but focus this planting on mineral soils with low soil carbon content • Reduce emissions from agriculture and improve efficiency at the same time • Use carbon enhancing management practices on mineral soils to increase soil carbon stocks • Choose appropriate management for soils / conditions – one size does not fit all • Consider implications for food security, rural livelihoods and displaced emissions • Bioenergy needs to be grown on appropriate land and should not displace woodland / natural habitats • Consider carefully food vs. fuel vs. conservation