On September 2, 2014, it began to rain heavily in Kashmir. Over the next few weeks, the excessive rain translated to flooding that left over 500 people dead in India and Pakistan.
A little more than a year earlier, in June 2013, intense rain battered Uttaranchal, causing landslides and exacerbating glacier melt, leaving thousands dead. And there was separate factor at play behind the sudden floods: the rupture of the Chorabari Tal – a lake formed by the retreat of the Chorabari glacier above the Kedarnath town. Experts think the lake probably burst because the heavy rain overwhelmed its boundaries.
So what does climate change have to do with this?
The International Panel of Climate Change (IPCC), the leading group of the world’s scientists says that glacier melting (retreat) and intense rainfall events are two leading manifestations of the warming weather.
While urban encroachment on the river floodplains definitely made the damage and death toll worse, the intense rainfall events and the glacier retreat were perhaps made worse by global warming.
What is climate change?
Climate change is the warming of the world caused by greenhouse gases that trap some of the heat emanating from the world which would have otherwise escaped into space. There are other pieces to this: the ozone layer, the carbon soot, other aerosols, the ice shielding parts of the world, the ocean circulation – all of which we shall look at later.
For now, let us look at the evidence close to home of the change in our climate. The primary manifestation is temperature.
It has gotten warmer. Chennai has warmed by One degree Celsius in the past 100 years. Rameswaram, near Madurai, is worse; it has got warmer by 1.5 degree Celsius in the last four decades! But surely One degree is not a big deal – even the variation between days is more than that.
A change of One degree Celsius for a few days, months or even a couple of years may lead to higher cooling costs and slightly worse tempers. The sustained warming of the climate is a big deal and has lasting negative impacts for the world, and especially for hot, dry countries like India.
What are the manifestations of climate change?
There are three key impacts of a sustained rise in temperature: ice melting, more humidity in the air and living things getting out of their comfort zone. We’ll dive into the first now, and leave the others for the next time.
When it is warmer than it has been in the past for a long time, ice melts. We have ice on top of mountains, glaciers and mainly, ice near the poles. For example, the Gangotri glacier has receded (or melted) by more than One km in the past 100 years. Most of that melting, 850 metre or so, has come in the past 25 years. Experts say the glacier is receding by 12 to 13 metre per year now. That is about ice area equal to five football fields every year melting out of Gangotri, and the same (or more) is happening across most of our world’s glaciers.
What happens to this enormous amount of water that is now available? It runs through rivers, causing more flooding on the way, into the ocean. We haven’t built the capability to divert some of this additional water runoff into our depleting groundwater aquifers (underwater storage of water), so most of it goes into the ocean or evaporates.
This brings us to another oft-mentioned impact of global warming: sea level rise. Researchers using NASA data have estimated that if all of the ice in the glaciers were to melt, the sea level would rise by 17 inches – a lot but not catastrophic.
But there’s more ice in this world – most of it is held in the gargantuan ice sheets in Greenland and in Antarctica. If the Greenland ice sheet were to melt entirely it would raise the sea level by Seven metres; if the Antarctic ice sheet were to completely melt, the sea would rise about 60 metres So, it is no surprise that the 40-member alliance of Small Island Developing States (SIDS in UN-talk) are amongst the most vociferous voices raised to call for curbing climate change. They stand to lose their homes, their country in the coming century.
Next time, we shall go deeper into the second impact: increasing humidity and the consequent changes in rainfall. That strikes far closer to home.
Climaction is a fortnightly column that is published in MetroPlus Weekend on alternate Fridays. The next article in this series will appear on February 6. Feedback and questions may be e-mailed to climaction2015@gmail.com
Mridula Ramesh is the Executive Director of Sundaram Textiles. She is also a student and teacher of global warming.
