ABSTRACT
Meteorological data and model projections suggest that significant climate changes are ongoing and are likely to continue over the course of the next century, requiring important land management and crop adaptations in order to sustain food supply to growing human populations. Global observations on surface air temperature (Hansen et al. 2010, Morice et al. 2012, and Vose et al. 2012) show that most parts of the Earth’s surface have already experienced notable warming over the course of the last century, with the longest observational dataset (HadCRUT4), indicating that global temperatures have risen to 0.72°C–0.85°C in the period from 1850–1900 to 2003–2012. Furthermore, the latest assessment report (AR5) from the Intergovernmental Panel on Climate Change (IPCC) (IPCC 2013) predicts that global surface air temperatures could increase as much as 4.5°C over the course of the present century. This projected rise in temperature is largely due to increasing atmospheric concentrations of greenhouse gases (GHGs), such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), which absorb energy emitted by the Earth’s surface (long-wave radiation) and retain a fraction of this energy in the atmosphere. Faster accumulation (than removal) of these gases in the atmosphere allows progressively more energy to be retained near the Earth’s surface, causing an increase in temperature.
