1. Negative emissions – potential social impacts

2. Starting point
We need negative emissions to prevent dangerous climate change
Without NETs need global peak by 2014 and 4% pa reduction after
For future generations, no NETs = significant negative impacts
But rapid mitigation also needed

3. BECCS Competition for land (food/biodiversity)
Food yields under threat (ozone, fisheries, water, soil, acidification, extreme weather, heat days)
Growing population, meat demand, biofuels further stresses situation
Biomass for NETs will add to strain
Localised air pollution
Cost
Ozone (yield loss by 2030 of 20% of soy, 25% of wheat?)
Fisheries (50% collapsed or overfished already?)
Water – 40% decline of cereal in China?
Soil, ocean acidification, extreme weather, etc

4. Food prices and conflict
Source: New England Complex Systems (2011 ) Economics of food prices and crisis

5. Enhanced soil & biomass sinks
Potential win-win better soil management and agriculture (but potentially short-term yield impacts)
Wetland restoration brings biodiversity & flood alleviation benefits (but opposition from some)
Afforestation – potential for ‘degraded lands’ but questions of ownership / biodiversity impact
Timber in buildings, etc but sources important

6. Olivine to soil
Potential run-off impacts – biodiversity and fisheries impacts
Local benefits for some acidic soils
Sourcing, grinding and transportation impacts
Possible local metal contamination over time

7. Ocean liming
Potential benefits around coral systems, important for hundreds of millions of people
Sourcing and transportation impacts, energy intensive

8. Ocean fertilisation
Impact on useful fisheries productivity even if total productivity enhanced

9. Air capture Energy requirements Safe storage sites
CCS site locations will be challenged
Visual impacts, local air pollution
Enhanced oil recovery
Cost

10. Scale, costs and TRL assessment

11. Conclusions
NETs bring costs to current and near-term generations above mitigation in many cases (distribution of costs is important)
Localised impacts will face opposition
Competition for land a major hurdle (food, land tenure)
Enhanced biomass and soil sinks are no-brainers
Air capture & ocean liming brings scale
Ocean fertilisation & olive to soil will be resisted
Offsets will increase opposition