Climate change has far greater repercussions than the mere inconvenience of an unbearably hot summer or even the worry of unpredictable winter floods. Climate change has a significant impact on the environment which can lead to severe changes in how we live – for example, climate change on a global scale will impact agriculture and affect world food supplies – and ultimately, the question may even be whether the human race can survive.
Global warming means that higher temperatures will be experienced in all regions of the world. In lower latitude regions, which are already warmer, this will mean that plants will release carbon dioxide, through the process of respiration, at a greater rate – which leads to a net drop in growth of crops and a poorer yield. In addition, higher temperatures can also accelerate physiological development, which results in premature maturation and therefore, reduced yield again.
Water is key to life – and especially to agriculture, of any kind. In fact, agriculture is the biggest user of water resources and an increased demand for water will force even more of a competition between agriculture and urban and industrial use.
One of the main consequences of climate change is the effect on rainfall, runoff water, evaporation and groundwater, as well as the storage of moisture in the soil. Climate change can lead to significant variation in the total seasonal precipitation. Even changes to the pattern of variability of precipitation can be important. These changes, plus the increase in evaporation and transpiration from plants, due to the higher temperatures, will inevitably lead to moisture stress. Moisture stress is very harmful to many crops during flowering, pollination and grain-maturation, especially the key crops of corn, wheat and soybean.
The need to increase irrigation for agriculture due to falling water tables, increased evaporation and disturbed precipitation means that more energy needs to be consumed to pump water, at greater financial and environmental cost – not to mention the additional demand for reservoirs, dams, well, canals and pumps. Some places may be removed from irrigation schedules altogether – a trend that has already begun in parts of North America – but this means a loss of the investment previously put into the land.
Extreme Climate Phenomena
The devastating tsunamis in South Asia and floods on the United States East Coast have more than emphasised the dangers of climate change and its impact on the environment. With increasing global warming and other climate factors, events like catastrophic flooding, droughts, heavy storms, unexpected blizzards, hurricanes and extreme heat waves will become more common – threatening not only crop production but human life and settlements as well.
The soil itself will be affected by global warming, as higher temperatures will increase the rate of decomposition of organic matter, as well as other soil processes – all of which will affect soil fertility. To counteract this, fertiliser application may be needed – and this will represent an additional cost to the environment, in terms of toxic chemicals in the water and air. Furthermore, warmer conditions will mean that the normal cycle of plant nutrients – carbon, nitrogen, phosphorus, potassium, and sulphur – from the soil through the plant and into the atmosphere, will accelerate, meaning that more carbon dioxide and nitrous oxide gases will be produced, contributing further to the ‘greenhouse problem’.
Global warming can also lead to greater soil erosion, as the drier conditions mean that root growth and decomposition of organic matter will be suppressed in the soil, thereby making it more vulnerable to wind erosion. To make matters worse, stronger gradients of temperature, combined with similarly strong gradients of pressure and increased atmospheric moisture means that heavier rainfall may result and this will cause even more soil erosion.
Pests and Diseases
Unfortunately, global warming creates conditions that favour the proliferation of pests and diseases. For example, warmer winter temperature mean that insect larvae can survive in areas where they are now limited by cold, resulting in greater infestations overall. Global warming can also affect wind patterns and this will have a knock-on effect on the spread of bacteria and fungi and other agents of crop disease (and human disease). All this increase in disease will of course provoke the greater use of chemical pesticides to try and control the situation and this will lead to further pollution to the environment and damage to our health.
Lastly, global warming threatens the very land we stand on. The melting of glaciers and sea-ice, together with the thermal expansion of sea water, mean that sea levels could rise by as much as 20 inches by the middle of the next century. Low-lying coastal regions, such as Egypt, Bangladesh, Indonesia, China, the Netherlands and Florida – as well as many island states – could be at serious risk. Even in areas which are not low-lying, coastal regions, the rise in sea levels could lead to difficulties draining surface water and groundwater, as well as sea-water intruding into estuaries and aquifiers – all of threatens agriculture and therefore our world food supplies, and also our general way of life.
These are simply some examples of the impact of climate change on the environment and they are more than enough to convince all of us to start becoming more ecologically-aware and making more environmentally-responsible choices.