Global climate change is recognised as one of the major current challenges to humanity. At
the same time, climate change is human induced and we hold the opportunity to react
accordingly. While global greenhouse gas (GHG) emissions continue to rise, emissions from
agriculture and land-use change (LUC) are levelling out albeit production growth and now
responsible for ~1/4 of anthropogenic emissions. Yet, while agricultural production needs to
increase further to feed our future demands for food and other agricultural products, we must
fast-track the process towards fewer emissions per produced unit.
This dissertation presents results and comprehensions from my PhD study on the basis of
three papers. The overall aim has been to develop a new identity-based framework, the KPI,
to estimate and analyse GHG emissions from agriculture and LUC and apply this on national,
regional and global level.
The KPI enables combined analyses of changes in total emissions, emissions per area and
emissions per product. Also, the KPI can be used to assess how a change in each GHG
emission category affects the change in total emissions; thus pointing to where things are
going well and where things are going less well in relation to what is actually produced. The
KPI framework is scale independent and can be applied at any level from field and farm to
global agricultural production.
Paper I presents the first attempt to develop the KPI identity framework and, as a case study,
GHG emissions from Danish crop production from 1992 to 2008 are analysed. We find that
emissions have been reduced by 12%, while yields per unit area have remained constant;
mainly due to a 41% reduction in nitrogen fertilizer use.
From this initial identity the KPI framework is further advanced to improve the output
metrics, and livestock production is included to encompass the comprehensive set of GHG
emissions from agricultural food production.
In paper II global agricultural production and GHG emissions since 1970 are analysed and
future business-as-usual (BAU) storylines are generated based on past trends in reduced
emissions per unit product. We show that agricultural production and GHGs have been
steadily decoupled over recent decades. Emissions peaked in 1991 at ~12 Pg CO2-eq. yr-1 and
have not exceeded this since. Since 1970 GHG emissions per unit product have declined by
39% and 44% for crop- and livestock-production, respectively. Only emissions from energy
use have increased more than production. Our projected BAU scenarios suggest that
emissions may be further decoupled by 20 – 55% giving absolute agricultural emissions in the
range of 8.2 to 14.5 Pg CO2-eq. yr-1 by 2050; lower than most other suggest from estimates
that do not allow for decoupling.
In Paper III agricultural production and GHG emissions since 1970, are analysed for nine
world regions. Decoupling of emissions from production shows vast regional differences. In
general, the more developed regions show the lowest emissions per unit of agricultural
production.
Although the calculations used in this research needs further improvements on several issues,
the KPI identity-framework poses a significant contribution to how we can improve our
understanding of emissions from agricultural production and the provided assessments are
very useful in pointing at critical issues towards reducing our climate footprints. A logical
next step for developing the concept of identities regarding food production could be to
integrate this production-based framework with identities on consumption and economic
development. It must be a scientific goal to illustrate how we best can provide the food we
need whilst reducing emissions efficiently; knowledge essential for establishing
comprehensive and ambitious climate change policy schemes.