If you are a biology student, you have surely heard about Locust, a swarm forming short horned grasshopper, in the family of Acrididae. These insects are harmless when solitary but in groups they are gregarious pest. A modest locust swarm can travel upto 200 kilometers and eat as much food as about 35,000 people in one day, according to Food and Agriculture organisation (FAO) of United Nations. This migratory pest has previously invaded Rajasthan in past two decades, including significant one last year. However, this year ‘Its the worst locust outbreak seen in a quarter of a century’ says officials. The difference this time is that Locusts have attacked areas where they have not been previously seen since 1993 and that too in very large numbers. The swarms have spread to parts of Madhya Pradesh, Uttar Pradesh and Maharashtra. Even National capital Delhi and surrounding regions have been kept on high alert, because if the wind favours, the swarm could reach these areas. I heard people saying, Why to worry when we have jetting machines, fire engines, and pesticides to tackle this problem. But worry you should! Because this is just another disastrous outcome of the global phenomenon- Climate change.
There have been studies that show the last five years have been hottest in our planet since the advent of industrial revolution. Since 1980’s each decade has been warmer than the previous ones. And this trend is expected to continue because of record levels of heat-trapping greenhouse gases in the atmosphere. Unexpected rainfalls, cyclones in one part of the world, to drought and forest fires in another part are all a result of climate change. One of the scenarios under Climate change is the increase in frequency of rainfalls due to warming of ocean waters. There have a been rise in the frequency of cyclones over the Arabian sea due to climate change. In 2018, cyclone Makunu hit parts of Saudi Arabia and Yemen, turning it into a watery landscape. Rainfall fell and gathered in different parts of deserts that borders Saudi Arabia, Yemen and Oman, making it breeding grounds for Locusts. Further, cyclone Luban that hit Arabian Peninsula in October 2018, created more favorable conditions for locusts to breed. There were unexpected rainfalls in Arabian Peninsula regions caused by Indian Ocean Dipole, a phenomenon accentuated by climate change. In January and February 2019, coasts of Red sea on the side of Africa and Asia received good rainfall. African side already has a locust problem and unexpected rainfall made good breeding grounds for them. Infact, last year Africa too witnessed one of its worst locust attacks. And when there was not enough food, locust swarms flew towards Arabian Peninsula where locusts have already grown due to two cyclones. They reached there in March 2019. The swarm then travelled to southern Iran from where they entered South Asia in April-may and June.
In June 2019, Monsoon started early in Thar desert making excellent conditions for Locusts to breed. Locusts need moisture in sand to breed which was provided to them in ample amount. The rainfall at that time provided them food supply in form of desert vegetation, like ‘Sewan’ (Lasiurussc indicus) and ‘Safed Dhaman’ or Cenchrusciliaris grass. Generally, Locusts leave India by November, but this did not happen in 2019 because they got every favorable condition they needed for survival and they stayed till January 2020. Here comes an interesting part, pests and animals can change their behavior and adapt to changing climate. So, locusts which leave India in winters, are now spending winters here.
When Locusts return to Southern Iran, they will be in for more conducive conditions during the onset of monsoon in India. The reasons why Locusts have been reported as early as April this year is because of excessive pre-monsoon rains this year and changing wind patterns over India and Pakistan. Infact, Pakistan declared emergency on February 2, 2020 after Locust swarms puts its food security at risk. Hence, we can say that worst Locust swarms that we are facing today is a cumulative effect of climate change The pre-monsoon rains are due Western Disturbances that visit India frequently, but that too visited early this year with larger than usual numbers of disturbances. At this point of time we cannot say whether increased Western Disturbances is because of climate change or not. Scientists are still working to figure out that part. You can read more about Western Disturbances in my previous post. Till then, don’t forget that Locust swarm’s mess can be intercepted because we have advance technologies today, and we are in hand prepared for problems before their arrival but the global problem of Climate change which is the root cause of such disturbances is the real issue here and we have absolutely no idea what else it has in store for us. Its high time that leaders across the world acknowledge this and take measures today so that we don’t have to deal with any bigger mess in future.
- Climate Change Brings the Worst Locust Attack in Decades to India-https://thewire.in/agriculture/locust-attack-india-jaipur-climate-change
- Locust attack: Plague a grim reminder of climate change’s reality- https://www.downtoearth.org.in/news/climate-change/locust-attack-plague-a-grim-reminder-of-climate-change-s-reality-69139
- Locust attack: ‘This is very, very rare’ :https://www.downtoearth.org.in/interviews/climate-change/locust-attack-this-is-very-very-rare–68992
- Climate Crisis Brings India’s Worst Locust Invasion in Decades- https://www.ecowatch.com/india-locust-invasion-climate-crisis-2646105181.html?rebelltitem=1#rebelltitem1