By Rumal Siriwardene and Vositha Wijenayake
On March 6, 2016, the Government of Sri Lanka launched the ‘Vasa Visa Nethi Ratak’ - a three-year programme aimed at curbing the use of agrochemicals and focusing instead on locally produced organic fertilizers. The government intends to prevent produce such as rice, vegetables and fruits from being tainted by toxic agrochemicals.
It has been widely reported that Sri Lanka annually imports approximately Rs.80 billion worth of agrochemicals. As Sri Lanka is a tropical country, this has alarming implications for its nitrogen dioxide emissions, since the humidity and heat cause higher amounts of nitrogen dioxide to be generated by the soil. 
 

Harmful impacts nitrogen dioxide 
Carbon dioxide, produced primarily as a result of burning fossil fuels, is the most dominant single source of greenhouse gas emission. Thus, climate change policies and legislations across the world focus primarily on cutting down carbon emissions from industrial activities. 
The detrimental effects of excess nitrogen dioxide in the atmosphere however, have not been given the same meticulous attention as carbon dioxide’s impact. Although the concentration of nitrous oxide in the atmosphere is considerably lower than that of carbon dioxide, the global warming potential of nitrous oxide is considered as being over 300 times greater. According to the International Panel on Climate Change (IPCC), for every 100 kg of nitrogen fertiliser applied to the soil, one kg ends up in the atmosphere as nitrous oxide (N2O). Also, nitrogen dioxide is the world’s most powerful ozone depleting substance. Due to these reasons, ignoring the impacts of N2O on climate change is not an option, and the global warming effect of nitrous oxide could be considered as extremely harmful as well as greater than the same amount of carbon dioxide released to the atmosphere. 
 

Agriculture and nitrogen dioxide emissions
The vast majority of nitrogen dioxide released into the atmosphere is produced from farming, where industrial scale agriculture practices have led to excessive nitrogen being added to the farmland, causing excessive leakage of nitrogen dioxide from the land. Thus, one of the most effective ways to curb emissions of nitrogen dioxide is to reduce the amount of nitrogen added to the soil via synthetic fertilizers. 
The 17 percent increase in the presence of nitrogen dioxide since the pre-industrial era has been attributed directly to the use of agrochemical fertilisers. The use of such fertilisers was truly globalised during the 1960s, with the advent of the ‘Green Revolution’ programmes which introduced chemical fertilisers to Asia and Latin America. A report by Grain, non-profit organisation that works to support small farmers and social movements in their struggles for community-controlled and biodiversity-based food systems outlines two destructive trends:
1. That the use of chemical fertilizer is on the rise in tropical regions, where the land produces higher rates of nitrogen dioxide
2. That the rate of emission of nitrogen dioxide increases exponentially as more fertiliser is applied. 
A very dangerous aspect of chemical fertilisers is that their efficiency is very limited, so farmers have to use increasing amounts of fertiliser every year in order to gain the same harvest. The Grain report estimates that over the past four decades, the efficiency of nitrogen fertilisers has decreased by two thirds but their use per hectare has increased sevenfold. 
 

Interrelated nature of agriculture and climate change
The United Nations Food and Agriculture Organisation states, “The intersection between climate change and agriculture is crucial to understanding the role agriculture plays in contributing to and mitigating global warming.” The role of organic agriculture - the use of natural fertiliser, diversifying crop production, etc. has been widely recognized for its potential to help farmers adjust to climate change.  Globally, trials have indicated that organic fertilization can sequester carbon dioxide from the atmosphere more effectively than synthetic fertilizers.
A 2008 global study (The International Assessment of Agricultural Knowledge, Science and Technology for Development) an intergovernmental study spanning three years with input from over 400 scientists, sponsored by the World Bank and other UN agencies, found that the use of agrochemical fertilisers can be stopped in favour of organic practices, without a reduction in crop yields. 
 

Powerful fertilizer lobby
According to Grain’s report ‘The Exxons of Agriculture’, the powerful lobbying efforts of the fertiliser industry must not be underestimated. The report states worryingly that 60 percent of the private sector members of the Global Alliance for Climate Smart Agriculture are from the chemical fertiliser industry. The report contends that the alliance itself was established to halt any real action on agriculture and climate change. Certainly, the presence of the world’s most prominent fertiliser companies in this alliance is troubling. 
It is important that in order to address climate change, and also to ensure a healthy life for the global population, the fertilizer companies and the private sector contributes to the efforts to mitigate the emissions of N2O, and the green house gases, and support the organic and healthy farming practices.