Physics behind the Climate Change
Nestled among the sugar bowl of western Maharashtra, having 500 years of history, known as grape capital of the region and being known for 240 years of yearly Rath Utsav and the land of tamasha and kushti - Tasgaon, a cute little town typically reminding us of the mix of north-south Indian culture is situated at 17 degrees North Latitudes and 74.6 degrees East Longitudes.
Maintaining traditional Rathotsava - Ganpati Chariot is moved around the city for the Elephant God’s City Sighting. Figure 1 is of the 30 feet wooden chariot decorated and pulled manually. Thousands of people visit tasgaon to witness this traditional event annually.
Figure 1: Traditional Rathostava in which a Ganpati Chariot with thousands of visitors
Figure 2: Tamasha - a dance cum drama form popularised in western Maharashtra.
Figure 3: Kushti is a popular sport in Maharashtra especially in Western region.
Figure 4: Tasgaon Map with its position in the district Sangli and the state of Maharashtra.
Given as Jahagir to Parshuram Bhau Patwardhan by Narayanarao Peshwa in 1774, this historical town Tasgaon town has a population of approx 38000 as per Census 2011. When an essay was to be written on the physics of climate change in our home town, I thought using google earth history images would be a good idea to highlight the effects of climate change. So first I chose my hometown, Tasgaon, a calm old town in south west Maharashtra known for grapes, sugarcane and turmeric.
Figure 5: Google Earth images of Tasgaon region for last 40 years
I tried to see its landscape each December for the last 50 years, thinking that it would be gradually drying till now, had there been climate change. Figure 5 below shows the images from the last few decades. It shows how its land use changed over time. The green cover indicates water availability as well. But seeing pictures I wouldn’t believe it. The landscape is getting greener and the present image is surprisingly better. Trying to reason this, I had two thoughts in mind. Either the satellite imagery is improved which is a possible reason. So I looked at corresponding parameters of rainfall. To my other surprise, the rainfall situation is almost the same as before. Frustrated on how I would represent this situation as a worse effect of climate change where actually the situation seems better. For once, I dropped the idea of writing the essay.
Another day, I had another thought which could possibly justify the change. Recently, due to the efforts of politicians of this region, the water canal network has improved especially in the last two decades. The supply from koyna dam and its tributaries has made water situations far better. This fairly explains why the situation is better here.
One such thing I explored was the Southern Maratha Gazette record which contains rainfall data of more than 100 years back.
Figure 6: A screenshot of gazetteer abstract indicating variable nature of yearly rainfall statistics. Excerpts taken from revenue survey of Southern Maratha Country (1888).
The above data is of pre-industrialization times and before the perceived effects of climate change induced variability started. It is evident from the monthly distribution of rainfall that the rain was spread over a longer time scale of a year i.e. for almost 7-8 months it was raining. This characteristic has changed now however the total rainfall per year is at the same level as also the annual variability. The variation in rainfall each year would still give a notion that during some years the rainfall is very high compared to a few years. Then also people would have attributed the change to the perception of climate change. There were no industries or machines.
Now, what about the essay and climate change? For a few days, the question struck me hundreds of times and had multiple reflections in my head. It was definitely not going out - Is climate change a myth?
How to understand what is happening? And is the whole world crying over climate change real? I was clueless about how I should present this reality. To verify the reality that I was trying to digest, I explored many areas of our country including rivers, mountains, cities, forests and adjacent oceans. I could not find any visible major change in the last five decades.
I then planned to report on Ahmedabad where I live and work. Its major business metropolitan city of more than 5 million population. There is a place called Nalsarovar 60 km west of Ahmedabad. It is a 120 square kilometer largest wetland bird century. It has endangered species of wild ass and black bucks and in winter thousands of migratory birds arrive here that includes pelicans and flamingos. Thousands of people arrive to watch these eye-catching sites. The area includes several small water bodies as well. I thought this place must have changed in the last few decades had the climate changed. Using google earth photographs of the last five decades again surprised me. The area looks much better, greener and watery now than before.
Figure 7: Google Earth images of Nalsarovar Lake region for last 40 years
Here also we could not see any visible major change in the area or water bodies or the greenery. In fact the situation is better now, it was bad in between. This was another puzzle. Had there been a major effect of climate change, there would have to be at least some indication which was absent in both the cases. I was convinced that taking any such sites in India would give the same results. The water bodies and greenery are definitely better now.
Then where is the change in climate? Climate wise situations may not be as alarming as we have their perception. We do have more extreme events of rainfall and temperature than before. However, it's difficult to ascertain who is to blame or is blaming justified?
The planet has warmed by over 1.1°C so far (Figure 8). There are five possible futures illustrated here. The lowest warming future requires rapid & sustained reductions in emissions & may keep warming close to 1.5°C. The middle future is roughly consistent with current global promises. However, this is not showing up in our figures shown and explained above.
Figure 8: Global average temperature is rising in the last 150 years and the future scenarios.
(Climate Visuals @github repository)
Natural causes of climate change:
The natural reasons attributed to the rise in temperature are the changes in earth’s orbit and rotation, variation in solar activity, volcanic activity, and change in earth’s reflectivity. These are all accepted reasons for the rise in temperature, we can’t do anything about this but to accept the situation.
The volcanoes increase cloud cover which results in short term cooling. Emitted sulfur dioxide mixes with water vapour and dust to form aerosols. Mount Pinatubo volcano erupted in 1991 which resulted in a 0.5 centigrade drop in global temperature. Gases in large volume and ash influence climatic patterns.
Earth’s orbit and its wobble shifts over thousands of years. The tilt change of the earth leads to significant changes in the strength of the seasons. The feedback mechanisms in the climate seem to amplify such changes.
The Sun is a variable star made up of gases so dense that the energy from its core takes hundreds of years to come out. Scientists have pointed out that the 20th century warming was due to an increase in the solar energy output. Solar irradiance varies, a well known event of little ice age between 1650 to 1850 is the example that the sun controls the environment on the earth.
The variability in ocean surface temperature is one more natural cause that brings change in climate. The El Nino event, which is the warming and cooling of the pacific ocean, brings terrific changes in Asian weather.
Man Made causes of climate change:
We have statistical data which indicates that the world is emitting more greenhouse gases than before, there are more industries than before, especially developing countries which use relatively older manufacturing processes emitting more gases and the global forest area in comparison to total area has come down. Use of fuel for transport is highest such that the fossil fuels are depleting fast and we require alternate fuels like electricity, solar etc.
Fossil fuels usage for electricity generation causes higher global greenhouse gases emission. These gases trap solar heat making the earth warmer. Manufacturing and mining industrial processes are also contributors of greenhouse gases. Every year we are removing 12 million hectares of forests. Forests are known to suck carbon dioxide and removing forests gives counterproductive results. An United Nations estimate suggests 25% of the greenhouse gases emanate from reduction in forests.
Similarly, more use of fossil fuels as transport mediums is also a contributor to greenhouse gases. It mainly emits carbon dioxide. Another 25% contribution to total greenhouse gases.
Use of fertilizers is increasing to match with the increased demand of food items. Presently, agricultural methods of food production especially in developing countries contain high energy consuming methods. Packaging and distributing industries of food products also contributes to emission.
Effect of Climate change on Economy:
The paths of economy and development due to climate change cross each other and result in increased risk and vulnerability. The requirement of rainfall would increase and ground water level would go down. The underground water bodies would not recharge on which Indian agriculture depends.
The Swiss Research Institute warns that the impact of climate change on world Gross Domestic Products could decrease 18% by year 2050 provided the global temperatures rise by 3.2 centigrade.
The warmer temperatures along with increasing extreme weather events and sea level rise will negatively influence property, infrastructure and impact human health. The agriculture, forestry, fisheries and tourism sectors are expected to be affected the most.
Climate is a global phenomena as one country’s emission affects all countries. Lower income countries are at more risk of economic impact of climate change.
As far as India is concerned, climate change would result in heavy economic losses in all manufacturing sectors. The rice, wheat and maize production will be impacted. The power generation requirement of developing countries like us would require heavy investments which would also impact the economy.
Higher incidence of diseases would be observed like diarrheal deaths will increase with decreasing incomes. The deaths due to Malaria and Dengue will also rise significantly till 2050.
Council on energy, environment and water puts an conservative estimate of 1 percent of GDP to be attributed as cost in mitigating climate change. Each 1 Centigrade increase in temperature would cost 4 percent loss of rice production, 32 percent loss of maize production and 5 percent loss of wheat production.
Further, ‘The costs of climate change in India’ reports economic costs of climate related risks. Extreme headwaves, flooding, storms and heavy rainfall would result in catastrophic costs. It slows the pace of poverty reduction and increases inequality. It would increase vector borne diseases. It suggests cleaner and efficient development paths to development. Methods of productions with low carbon footprints would result in cleaner air, more energy security and fast job creation.
Conclusion:
People perceive that the rainfall patterns have changed with less rainy days and more rainfall on rainy days compensating to the same net rainfall but due to its extremity in populated areas it results in casualties. Similarly lateral heat distribution has changed in such a way that there are pockets of extra high as well as extra cool temperatures. This also results in calamities. We search for ‘why’ this would have happened.
People understand climate change mainly as global warming? Besides now extreme events like heat waves, Excess rains, More frequency cyclones are attributed to changing climate?? Is science sure about the change? Or we are yet to understand what’s happening?
People/Society have an appetite to adapt to the change. Change is only a constant thing as explained in many verses of Bhagavad Gita elicited by Bhagwan Shri Krishna. When a duration of scanty rainfall came, people of tasgaon switched to different crops with less water and alternate methods like drip irrigation. And when the situation improves, as now, get back to water rich crops like sugarcane.
References:
Climate Visuals @github repository
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