The devastating Chennai flood (Nov-Dec 2015) is the full blown effect of global warming – says experts, like the heat wave in Telangana that killed hundreds of people.
But how sure are we that humans are the major cause of global warming
The practice of linking weather events to human influence, such as global warming is difficult to substantiate. However, only in the last few years, the Earth’s average temperature has been rising from the mid-20th century and onwards. And climate change is associated with increased levels of atmospheric anthropogenic carbon dioxide and methane gas.
IPCC scientists in the Fourth Assessment Report conclude that they are 90% sure that there is direct evidence that emissions of heat-trapping gases such as carbon dioxide from human activity have caused almost all of the observed increase in globally averaged temperatures since the mid-20th century and that the atmospheric concentration of carbon dioxide has increased from the pre-industrial era of 100 years (1750-1850).
Adverse effects of climate change on the Earth
The adverse effects of climate change on the Earth due to global warming are almost daily events we see. Its physical impact is causing serious inimical consequences on our environment and subsequently on human social and economic systems.
Experts predict that fierce storms and floods are likely to become more and more frequent in the future. Higher temperatures, fresh water shortages, higher sea levels and extreme weather events
will each affect regions differently – depending on the nature and level of climate change, especially with continuing greenhouse gas emissions.
The adverse effects are many but can be broadly grouped under the following categories:
(1) Rising temperature with extreme weather conditions
(2) Water and food scarcity
(3) Potential impacts on human activity and health issues
(4) Impact on wildlife with altered habitats, species extinction
Rising temperature relates to extreme weather conditions
Experts believe that global temperature may rise between 1.1 and 6.4 degrees Celsius above 1990 levels by the end of the 21st century if concrete steps are not taken to reduce greenhouse gas emissions. The Earth’s current average temperature according to NASA figures is 15C. The possible climatic change will cause extreme weather conditions. There will naturally be more heat waves, droughts and flooding more than what we are seeing now globally.
Water and food scarcity
Water and food scarcity are the main challenges under climate change because of the substantial reduction in fresh water resources and agricultural yield. Study of Global Climate Models (GCMs) projects significant changes to regional and globally averaged precipitation and air temperature, and these changes will likely have associated impacts on groundwater recharge. As a result, there will be food shortages from the land and sea for a large proportion of life on this planet.
Potential effect of climate change on human activity and health issues
Climate change is already beginning to impinge on life on the Earth. Extremes of temperature and rainfall, such as heat waves, floods and droughts have direct effect on human and animal mortality, as well as long term effects. It will affect biodiversity and the ecosystem of goods and services that we rely on for human health. It has also been observed that even small temperature changes can result in measurable impacts on malaria, diarrheal diseases and malnutrition. From the knowledge of these relationships an approximate estimate of the health effects of the future due to climate changes can be made.
Impact of climate change on animals, birds and plants
Animals, birds, plants and entire ecosystems are on the move as rising temperatures force species to seek out cooler climes. There are higher rates of tree death and increasing dieback of forests in the last two decades. As Arctic climate is more sensitive to global warming, the shrinking of ice in the Polar Regions over the next 100 years will have a severe damaging effect on Arctic wildlife, such as polar bears and seals.
Scientists at Stanford University in America, using fossil records and extinction counts have in 2015 calculated the normal ‘background rate’ of extinctions and compared it with a conservative estimate of current extinctions. Professor Paul Ehrlich at the Stanford Woods Institute for the Environment said: “Species are disappearing up to about 100 times faster than the normal rate between ‘mass extinctions’. Earth has entered its sixth ‘mass extinction’. Humans have created a “toxic mix” of habitat loss, pollution and climate change, which has already led to the demise of at least 77 species of mammals, 140 types of birds and 34 amphibians since 1500.
In India, realising the potential adverse effect of climate change, it was great statesmanship that Prime Minister Manmohan Singh on June 30 2008, released India’s first National Plan on Climate Change (NAPCC) outlining existing and future policies and programmes, addressing climate mitigation and adaptation. While emphasising the overriding priority of maintaining high economic growth rates to raise living standards, he pledged that India’s per capita greenhouse gas emissions “will at no point exceed that of developed countries even as we pursue our development objectives.”
Climate scientists believe that global temperature will continue to rise for decades to come, largely due to greenhouse gasses produced by human activities though the effects on climate change will vary all over the globe. They predict increases in global mean temperature of less than 1 to 3 degrees Celsius (1.8 to 5.4 degrees Fahrenheit) above 1990 levels. This will produce beneficial impacts in some regions and harmful ones in others. Net annual costs will increase over time as global temperature increases.
Personally I believe, though scientific confidence with observed data is currently not complete, the underlying mechanisms of climate change are expected to play.
PS. NASA with photographs, reveals that Antarctica is actually gaining more ice than it is losing, despite fears over global warming.
The writer is based in the UK