Climate change is one of the defining issues of our time. It is now more certain than ever, based on many lines of evidence, that humans are changing Earth’s climate. The atmosphere and oceans have warmed, accompanied by sea-level rise, a strong decline in Arctic sea ice, and other climate-related changes. These changes will have an enormous impact on our planet’s people, ecosystems, cities and energy use and these effects will be felt most by the world’s poorest and most marginalised communities living in regions that are susceptible to changes in the climate and whose livelihoods are dependent on natural resources.
The warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global mean sea level. Earth’s average surface air temperature has increased by about 0.8°C (1.4°F) since 1900, with much of this increase taking place since the mid-1970s. Although a wide range of other observations and indications together provide incontrovertible evidence of global warming, the clearest evidence comes from the widespread thermometer records.
Previously, the year 1998 was the warmest and the 1990s the warmest decade on record. But, the year 2015 has broken all records and almost every month of it was termed the warmest ever. This shows that the Earth has warmed at an unprecedented rate over the last hundred years and particularly over the last two decades.
Exactly how much warmer the atmosphere gets will depend on how quickly and effectively people can substantially reduce the activities that are causing rising temperatures.
There are two main causes of climate changes: natural and manmade. The Earth’s climate is affected by natural factors such as changes in volcanic activity, solar output, and the Earth’s orbit. Human activities that most affect the climate include the burning of fossil fuels and the conversion of land for forestry and agriculture.
The earth’s climate is dynamic and constantly changing through a natural cycle. The natural variability and the climate fluctuations have always been part of the Earth’s history. Although there are a number of natural factors responsible for climate change, some important of them are continental drift, volcanoes, ocean currents, the earth’s tilt and comets and meteorites.
Nearly 250 million years ago, all the continents made one large land mass known as Pangea. Then they gradually began to drift apart and formed the separate continents. The formation of separate continental land masses changed the flow of ocean currents and winds, and isolated Antarctica. The position of continents and the continental drift had an impact on the climate because it changed the physical features of the landmass, their position and the position of water bodies. This drift of the continents continues even today; the Himalayan range is rising by about 1 millimeter every year because the Indian landmass is moving towards the Asian land mass, slowly but steadily.
Another natural cause of climate change is volcanic activitey. When a volcano erupts, it throws out large volumes of sulphur dioxide (So2), water vapour, dust and ash into the atmosphere. Millions of tonnes of SO2 can reach the upper levels of the atmosphere (stratosphere) from a major eruption. The gases and dust particles partially block the incoming rays of the sun, leading to cooling. Volcanic eruptions of high magnitude can reduce the amount of solar radiation reaching the Earth’s surface, lowering temperatures in the lower levels of the atmosphere (called the troposphere), and changing atmospheric circulation patterns. Although the volcanic activity may last only a few days, yet the large volumes of gases and ash can influence climatic patterns for years.
Beside these two, changes in earth’s orbit also cause changes in the climate. The earth makes one full orbit around the sun each year. It is tilted at an angle of 23.5° to the perpendicular plane of its orbital path. For one half of the year, when it is summer, the northern hemisphere tilts towards the sun. In the other half i.e. the winter, the earth is tilted away from the sun. Changes in the tilt of the earth can affect the severity of the seasons.
In addition to these, the oceans are a major component of the climate system. They cover about 71% of the Earth and absorb about twice as much of the sun’s radiation as the atmosphere or the land surface. Ocean currents move vast amounts of heat across the planet. Since the oceans are surrounded by land masses, therefore heat transport through water is through channels. Furthermore, ocean current is one of the natural causes that effect climate change. The changes in ocean circulation will affect the climate through the movement of carbon dioxide into or out of the atmosphere.
Climate change can also be caused by human activities, such as the burning of fossil fuels and the conversion of land for forestry and agriculture. Since the Industrial Revolution, human influences on the climate system have increased substantially. In addition to other environmental impacts, these activities change the land surface and emit various substances to the atmosphere. These in turn can influence both the amount of incoming energy and the amount of outgoing energy and can have both warming and cooling effects on the climate. The overall effect of human activities since the Industrial Revolution has been a warming effect, driven primarily by emissions of carbon dioxide and other greenhouse gases.
The build-up of greenhouse gases in the atmosphere has led to an enhancement of the natural greenhouse effect. It is this human-induced enhancement of the greenhouse effect that is of concern because ongoing emissions of these gases have the potential to warm the planet to levels that have never been experienced in the history of human civilization. Such climate change could have far-reaching and/or unpredictable environmental, social, and economic consequences.
In South Asia, flooding, food shortages, and stagnating economic growth are just some of the devastating impacts that we may experience due to advancing climate change, according to the United Nations. The IPCC 4th Assessment Report “Climate Change 2014: Impacts, Adaptation, and Vulnerability” states that climate change, in particular, increased risk of floods and droughts, is expected to have severe impact on South Asian countries, the economies of which rely mainly on agriculture, natural resources, forestry and fisheries sectors. The report’s conclusions and projections thereupon are stark and sobering. Even under the most modest assumptions about emissions growth, the future effects of climate change will be felt worldwide especially in South Asian countries —Afghanistan, Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan, and Sri Lanka.
These fears were further reinforced by a long heat wave in Karachi that claimed hundreds of lives. Scientists have warned for some time now that heat waves will become more frequent and intense due to climate change.
Another manifestation of it came when Nepal suffered a massive earthquake in April 2015 which killed over 9,000 people. This quake was the largest one in the region in the past 8 decades. Soon after the quake, a debate ensued that it is the result of the climate change. The untold – and terrifying – story behind the earthquake reveals that it’s the result of the ebb and flow of rainwater in the great river deltas of India and Bangladesh, and the pressure that puts on the grinding plates that make up the surface of the planet. University College London’s Prof Bill McGuire, professor emeritus of Geophysical and Climate Hazards, believes that “Climate change may play a critical role in triggering certain faults in certain places where they could kill a hell of a lot of people.”
Moreover, torrential rains and the resultant heavy flooding recently submerged Chennai in India. In addition to loss of human lives, three million people were left without basic services, the cost of which is estimated at more than US$225 million. Indian premier, Narendra Modi, insisted: “We are seeing the impact of climate change now. The unseasonal rains resulted in the floods in Tamil Nadu. We have witnessed heavy rains in non-monsoon weather.”
When it comes to mitigation efforts, we find that the Montreal Protocol on Substances that Deplete the Ozone Layer was first such effort. It designed to reduce the production and consumption of ozone — depleting substances in order to reduce their abundance in the atmosphere, and thereby protect the earth’s fragile ozone Layer. The original Montreal Protocol was agreed on 16 September 1987 and entered into force on 1 January 1989.
Considered a major multilateral success, the Protocol is persistently touted as the prime example of how well nations can work together on global environmental issues. But why was it successful? The Montreal Protocol had the perfect combination of factors: hegemons (US and UK) taking the lead, a short timeframe before the ozone was projected to dissolve, a great mutuality of interests among the attending parties, and concentrated benefits with distributed costs.
The second big effort came when after two and a half years of intensive negotiations, a substantial extension to the Convention was adopted in Kyoto, Japan on 11 December 1997 and it entered into force on 16 February 2005. Under the Kyoto Protocol most developed nations other than the US committed themselves to targets for cutting or slowing their emissions of the key greenhouse gases that cause climate change. The targets varied between nations. Some were allowed to increase their emissions by a certain amount; others were required to make significant cuts. The average target was a cut of around 5% relative to 1990 levels by 2012 (or more accurately 2008–12).
Another major effort on arresting climate change was seen in the 2015 United Nations Climate Change Conference, or COP 21, that was held at Le Bourget, near Paris, in France from November 30 to December 11. After nearly two weeks of tough haggling for a climate rescue pact, representatives of 195 nations reached a landmark accord that will, for the first time, commit nearly every country to lowering planet-warming greenhouse gas emissions to help stave off the most drastic effects of climate change.
Commenting on the agreement, United Nations Secretary General, Ban Ki-moon, said:
“This is truly a historic moment. For the first time, we have a truly universal agreement on climate change, one of the most crucial problems on earth.”
The agreement, if faithfully carried out, will achieve far larger cuts in emissions than any previous accord. It will reduce, without eliminating, the risk that runaway climate change might render parts of the Earth uninhabitable. It will lessen somewhat the possibility of a collapse of one of the ice sheets, which would cause a rise of 20 feet or more in the sea.
Now, let’s discuss the possible effects of climate change.
In 2014, the US Department of Defense published the Climate Change Adaptation Roadmap, outlining defence and security issues in relation to climate change. The department warned that climate change was a ‘threat multiplier,’ in that it stands to intensify already-acknowledged security threats such as resource scarcity, disease, drought and displacement. Regions that are ill-equipped to handle this onslaught of problems may be susceptible to the spread of extremism.
It’s no secret that climate change is expected to cause massive problems related to migration. People are already beginning to seek refuge, with the world’s first climate refugees—a family from the Polynesian island nation of Tuvalu — having been granted residency in New Zealand in 2014 due to rising tides. In 2014, a staggering nearly 60 million people sought refuge in other countries due to war, poverty, resource scarcity, natural disasters and other problems, according to the UN Refugee Agency.
Besides creating a perplexing refugee crisis, the climate change phenomenon is also threatening the food security.
Climate change is likely to diminish continued progress on global food security through production disruptions that lead to local availability limitations and price increases, interrupted transport conduits, and diminished food safety, among other causes. A major scientific assessment released by the US Department of Agriculture (USDA) indicates: “If society continues on a path of high emissions of greenhouse gases, there is no way around the fact that climate change is going to be a primary challenge for producing and distributing food.”
Pope Francis says, “We must not forget the grave social consequences of climate change. It is the poorest who suffer the worst consequences.”
Climate impacts have shown to hit the developing world’s poor the hardest partly because they are more likely to be dependent on the very resources impacted and partly because they have far lesser capacity to protect themselves. The phenomenon is already contributing to the deaths of nearly 400,000 people a year and costing the world more than $1.2 trillion, wiping 1.6% annually from global GDP. By 2030, the researchers estimate, the cost of climate change and air pollution combined will rise to 3.2% of global GDP, with the world’s least developed countries forecast to bear the brunt, suffering losses of up to 11% of their GDP.
Although Pakistan is one of the lowest emitters and accounts for less than 1pc of the total global carbon emissions, yet it remains at the forefront of the devastating impacts of climate change. The year 2015 has proved to be an unusual one for Pakistan due to unpredictable weather events. A mini-cyclone in Peshawar killed 44 people, heat waves in Karachi killed more than 1,500 people, cloudbursts in various areas of Gilgit-Baltistan affected 35,717 people, while floods across the country killed 238 and affected more than 1.5 million people.
The climatic changes, having huge negative impacts on Pakistan, as well as several natural disasters including floods and droughts have threatened the agriculture and agri-based communities of the country.
The whole discussion can be summed up in the following words
“If we want to address global warming, along with the other environmental problems associated with our continued rush to burn our precious fossil fuels as quickly as possible, we must learn to use our resources more wisely, kick our addiction, and quickly start turning to sources of energy that have fewer negative impacts.”
– David Suzuki