Warming Trends

By Ranil Senanayake –October 23, 2015

Ranil Senanayake

This year is a signal of things to come and yet, not only are we ill prepared for the effects of climate change, but we are also gleefully adding to the problem by burning more and more fossil fuels to supply our energy needs. The new studies on global temperatures suggest that they will exceed all records this year. The map below that depicts the rise in temperatures over average suggests that we narrowly escaped a disastrous heat wave. The map shows Sri Lanka only just above the ‘record warmest’ band.

Why is a heat wave so dangerous? Apart from the heat stress in human and animals, it could exceed the threshold for enzymatic activity. All of agriculture depends on the good growth of plants, all plants rely on their chlorophyll to grow and produce. Chlorophyll is a molecule that functions to an optimum at about 37degrees, above that their performance falls. In heat waves often exceeding 38 degrees plant productivity will be impacted and yields drop (fig2). This year much of Australia dealt with a brutal spring heat wave that reduced farmers’ yields.

Fig.1

The danger to agricultural production is further exasperated by the reliance on chemical farming with so-called ‘high yield ‘ crops. These crops have been bred by reducing photosynthetic biomass for crop biomass. This reduction being made possible by the use of chemical fertilizers. But in a high temperature situation when chlorophyll is functioning sub-optimally such reductions may bring serious crop losses.

Fig. 2

Chemical fertilizers are produced using large amounts of energy, usually fossil energy. The creation of this fossil energy results in the discharge of huge volumes of Carbon Dioxide into the atmosphere. Therefore chemical farming adds greatly to global warming, that creates the dangerous heat waves around the planet and finally affects the farmer through increased heat stress on the crop.Read More