Climate change and agriculture are always related. Climate change affects agriculture and agriculture causes climate change. Agriculture increases level of climate change by following sources. Particulate matter & GHGs from land clearance by fire & burning of residues, methane produced from the bacterial rot of agricultural organic matter, greater than total global anthropogenic emissions of CH₄ and N₂Ois from agriculture. The major emission of methane comes from rice and livestock cultivation and nitrous oxide comes from fertilizer and manure decomposition. CO₂ emissions from Field work, machinery and production of fertilizers & pesticides is also seen.

 The impacts of climate change on agriculture are seen as follows:

Temperature: In mid to high latitudes moderate warming may benefit cereal crop, but in seasonally dry and tropical regions even slight warming decreases yields.

  Precipitation –Precipitation is expected to increase in high latitudes and decrease at mid to low latitudes although there is high regional and seasonal variation in the level of certainty in these projections.

Extremes  Changes in the frequency and intensity of extreme weather events will have significant consequences for agriculture. Increases in extreme temperature events can have high impacts on crop yields. Increasing occurrence of drought is projected for many important agriculture regions. Extreme rainfall and flooding may also have severe consequences for agriculture at the local scale and can effect grain quality as well as quantity.

•         Water Resources – Large areas of agriculture exists in catchments dominated by snow and glacier melt. Climate change will shift the seasonality of water availability in these areas causing earlier and more intense runoff.

•         Tropical storms and Sea Level Rise –Climate change is projected to decrease frequency but increase intensity of tropical storms, although this is highly uncertain. Sea level is set to rise as a consequence of increasing global temperatures. Both will increase the vulnerability of coastal and low lying agricultural areas to factors such as coastal inundation, soil salinisation and intense rainfall.

   CO₂ Fertilization – Evidence suggests that total crop yield may rise when averaged across the globe due to effects of CO₂ fertilization, which is expected to offset negative impacts of a changing climate. The accuracy of these projections and thus future food security depend critically on the magnitude of the CO₂ fertilization effect under actual growing conditions. Elevated CO₂ is thought to decrease grain quality.

•         Pests & Pathogens – Rising temperatures may alter the frequency and intensity of pest and pathogen outbreak. However, crop/ pest interactions are complex and poorly understood in the context of climate change.

•         Indirect impacts: Changing crop-weed competition dynamics, range changes of pests & pathogens, expanded range predicted for many pathogens, less-cold winters allow increase in pests, different range changes between pests & pathogens and natural controls and decreased biodiversity in natural ecosystems

So, to conclude, the impacts on farming without action are mostly negative:

–        Hotter and drier places will produce less

–        As in these places the soil will become poorer

–        Places liable to saltwater flooding will become unproductive.

–        Warmer and wetter places are more likely to suffer from disease, lowering the yield.

But

–        Places in the higher latitudes (nearer the poles) are getting a longer growing season and so can produce more and different things than they have managed before.