Imran Choudhary
Glaciers are melting, sea levels are rising,cloud forests are drying, and wildlife is scrambling to keep pace. It’s becoming clear that humans have caused most of the past century’s warming by releasing heat-trapping gases as we power our modern lives. Called greenhouse gases, their levels are higher now than in the last 650,000 years. We call the result global warming, but it is causing a set of changes to the Earth’s Climate or long term weather patterns, that varies from place to place. As the Earth spins each day, the new heat swirls with it, picking up moisture over the oceans, rising here, settling there. It’s changing the rhythms of climate that all living things have come to rely upon.
Global warming is the rise in the average temperature of Earth’s atmosphere and oceans since the late 19th century and its projected continuation. Since the early 20th century, Earth’s mean surface temperature has increased by about 0.8°C with about two-thirds of the increase occurring since 1980. The Scientific consensus is that a significant proportion of this past rise, particularly in the last 25-50 years, is due to humanity’s emission of greenhouse gases such as carbon dioxide (Co2).
Global Warming is affecting the basic elements of life for people around the world- access to water, food production, health and the environment. Hundreds of millions of people suffer hunger, water shortages and coastal flooding as the world warms.
The rapid rise in greenhouse gases is a problem because it is changing the climate faster than living beings are able to adapt. Also, a new and more unpredictable climate poses unique challenges to all life.
Greenhouse Effect
The “greenhouse effect” is the warming that happens when certain gases in Earth’s atmosphere trap heat. These gases let in light but keep heat from escaping, like the glass walls of a greenhouse.
First, sunlight shines onto the Earth’s Surface, where it is absorbed and then radiates back into the atmosphere as heat. In the atmosphere, “greenhouse’ gases trap some of this heat, and the rest escapes into space. The more greenhouse gases are in the atmosphere, the more heat gets trapped.
Scientists have known about the greenhouse effect since 1824, when Joseph Fourier calculated that the Earth would be much older if it had no atmosphere. This greenhouse effect is what keeps the Earth’s climate livable. Without it, the Earth’s surface would be an average of about 60 degrees Fahrenheit cooler.
Levels of greenhouses gases (GHGs) have gone up and down over the Earth’s history, but they have been fairly constant for the past few thousand years. Global average temperatures have stayed fairly constant over that time as well, until recently. Through the burning of fossil fuels and other GHG emissions, humans, are enhancing the greenhouse effect and warming Earth.
Scientists often use the term “climate change” instead of global warming. This is because as the Earth’s average temperature climbs, winds and ocean currents move heat around the globe in ways that can cool some areas, warm others, and change the amount of rain and snow falling. As a result, the climate changes differently in different areas.
Impact of Global Warming
Global Warming have very serious impacts on earth’s climate, growth and development.
If no action is taken to reduce emissions, the concentration of greenhouse gases in the atmosphere could reach double its pre-industrial level as early as 2030, virtually committing us to a global average temperature rises of over 2°C. In the longer term., there would be more than a 50% chance that the temperature rise would exceed 5°C. This rise would be very dangerous indeed; it is equivalent to the change in average temperatures from the last ice age to today. Such a radical change in the physical geography of the world must lead to major changes in the human geography- where people live and how they live their lives.
Now, with concentrations of greenhouse gases rising, Earth’s remaining ice sheets (such as Greenland and Antarctica) are starting to melt too. The extra water could potentially raise sea levels significantly.
As the mercury rises, the climate can change in unexpected ways. In addition to sea levels rising, weather can become more extreme. This means more intense major storms, more rain followed by longer and drier droughts (a challenge for growing crops), changes in the ranges in which plants and animals can live, and loss of water supplies that have historically come from glaciers.
Ozone Depletion
*The Ozone layer is found in the atmosphere between 15-30 km from the earth’s surface.
*The Ozone layer is a region of concentration of the allotrope of an oxygen molecule known as ozone (o3), which is produced by the action of solar radiation.
*It filters sunlight and prevents the harmful ultraviolet radiation from reaching the earth’s surface by absorbing most of the ultraviolet radiation.
*If these ultraviolet rays were to reach the earth’s surface in full intensity, all exposed bacteria would be destroyed and animal tissues damaged severely. These are certain household and industrial chemicals, having widespread application in refrigeration, air conditioning, fire extinguishing and dry cleaning, that are known to deplete this life -saving layer.
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