school energy&environment

Agriculture and climate change

Earth’s climate is changing and there is scientific evidence about this. The average temperature of the planet has been rising by 0,8 °C in the past century (in Europe it has been rising by 1 °C). It’s been time since some gases have been identified as causes for global warming and the so-called “greenhouse effect”, especially carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O), naturally occurring in the atmosphere, but produced in high concentrations by human activity, as the use of fossil fuels for transportation and industrial activities, land-use change and deforestation. General climatic conditions have become more variable. Rainfall has increased in northern European regions together with the frequency of hurricanes and storms, whilst in southern regions is occurring a decline in rainfall and increased drought. Statistical analyses show that the risk of catastrophic events taking place in the future is increasingly higher along with related potential economic losses.
Southern Europe and the Mediterranean Sea basin, in particular, are among the areas at greater risk of drought, whilst mountainous areas as the Alps risk undergoing deep changes in the structure of glaciers and water flows due to temperature rise. In the following decades, cultivated lands will probably undergo great variability of annual yielding times as harvesting will be anticipated to summer and starting crop rotations will be necessary in spring, introducing species requiring less water in comparison to corn and the few selected crops currently selected. In the light of the great impact of climate change occurring on the whole planet in the medium and long term, the political background governing and shaping the policies of each country with regards to the agricultural sector is expected to face a double challenge: on one side, the necessity of reducing atmospheric emissions of “greenhouse gases” (GHG), and on the other side, the need to adapt human activity to new climatic conditions to reduce its negative impacts on humans. In particular, agriculture could contribute greatly to the mitigation of climate change, considering its strong impact on the environment: it can, in fact, reduce high methane and nitrous oxide emissions (generated from manure used to fertilize and related zootechnical activities), enhance the capacity of cultivated lands of absorbing carbon dioxide from the atmosphere, provide useful raw materials to generate renewable energy.
And how does agriculture affect climate change?
Agriculture represents the third most important sector with regards to greenhouse gases emission, in close correlation with the livestock sector, as it produces 9% of total GHG emissions in the atmosphere generated by human activities The greatest agricultural impact is given by nitrous oxide (N₂O) emissions generated by the application of fertilizers on farming soils (5%), followed by methane (CH4) emissions generated by manure and ruminant digestive processes. The role played by agriculture with regards to atmospheric emissions depends, in fact, from the type of farm located on a territory and intensive or extensive livestock activities taking place. Moreover, it should be considered that greenhouse gas emissions generated by agricultural activites requiring energy use (for example, fuel for machinery, electricity for lighting and to carry out activities within plants, etc.) aren’t estimated, according to common European policies, within the emissions produced by the agricultural sector but are assigned to the energy sector. The same goes for the evaluation of carbon which can be naturally absorbed by soil (a phenomenon termed “carbon sequestration”), helping to reduce excessive carbon dioxide in the atmosphere: this type of activity isn’t considered within the agricultural sector, but estimated in relation to soil use and land-use change. For these reasons, measuring the impact of agriculture on climate change is more complex than for other sectors as the industrial sector, as estimates of greenhouse gases emissions produced by agricultural systems must also take into account biological and environmental processes involved.