Effects on Agriculture

The Overall Picture

Based on current projections elicited by reputable scientific organizations, increase in global temperatures due to the input of GHGs into the atmosphere will cause a myriad of repercussions, such as increased temperature and CO2 levels, changes in precipitation, and prevalence of extreme events such as drought. Looking in terms of agriculture on a global scale, the average crop yield is projected to decrease, and populations in developing countries which already face issues related to food security and crop yield will be the most negatively affected.

Future projections in crop yield

Factors that may influence agricultural productivity

Average temperature increase can have various consequences in agricultural productivity as the growing season will be lengthened, especially in regions with a colder spring and autumn. In addition, temperature increase may adversely affect crops that are already limited in production by hot summer temperatures, thus a further increase will add to decrease in crop yield and productivity. Subsequently, the frequency and chances of droughts increases with temperature due to increase in soil evaporation rates

Changes in precipitation may affect the level of soil moisture, and the increase in acid rain brought upon by increased greenhouse gas emissions may increase soil erosion rates. Both soil moisture and erosion rates are key factors in determining crop yields, and current projections by the IPCC predicts that higher precipitation will be observed in high latitudes, with a decrease in tropical regions.

Changes in CO2 levels are also important in determining agricultural productivity. Intuitively, it makes sense that rising concentrations of CO2 will increase crop yield as plants utilizes CO2 when performing photosynthesis. Thus, higher levels of CO2 may act as a long term fertilizer, and will most likely lead to a positive impacts.

Changes in occurrences and severity of extreme events such as drought, floods, and storms pose a huge threat to agricultural productivity. Although current models are fairly uncertain in future extreme events, the onset of these events would hinder agricultural productivity.

Currently, the effects of climate change on agriculture at a global scale appears to look abysmal in terms of future outlook and crop yield. According to the United Nations Food and Agriculture Organization, agricultural growth is expected to decline from 2.2% per year (From the last 30 or so years) to around 0.8% per year at around the year 2030 due to climate change. Essentially, this prediction in agricultural growth would have negative effects (hunger) unless there is an 80% increase in agricultural output by the year 2050. However, in order for this to take place, crop land would have to increase drastically to compensate for this decline in agricultural growth. Currently, around 820 million people in developing countries are considered malnourished. Unless new innovations in regards to crop yield or reductions in fossil fuel emissions take place, this number is expected to increase.

Projected Maize Yield for Increased Temperatures

Projected Wheat Yield for Increased Temperatures

Projected Rice Yield for Increased Temperatures