Original English Article
Written by: Ed Grabianowski
Terminologies used in this article:
| air conditioner = তাপানুকুল যন্ত্র; byproduct = উপজাত; chain reaction = শৃঙ্খলিত প্রতিক্রিয়া; combustion = দহন; coral reef = প্রবাল প্রাচীর; cropping season = ফসলী ঋতূ; data = উপাত্ত; desertification = মরুকরণ; |
ecosystem = বাস্তুতন্ত্র; feedback = ফীডব্যাক; glacier = হিমবাহ; global warming = বৈশ্বিক উষ্ণায়ন; greenhouse effect = গ্রীনহাউজ প্রতিক্রিয়া; infrared radiation = অবলোহিত বিকিরন; landfill = আবর্জনাভূমি, বর্জ্যভূমি |
1.
What is Global Warming
The terms “Global Warming” or “the Earth’s rising temperature” are relatively new. Not long ago, only a handful of scientists who were becoming increasingly aware of climate changes due to decades-long environmental pollution really understood what those words meant. Nowadays, even if not everyone fully understands global warming, most people are at least aware of the issue. That’s why, when someone sees a hot day or a strange storm and says “That’s global warming,” it doesn’t seem unusual anymore.
That’s right! In this article, we will discuss what global warming is, its causes, and the possible effects. However, not everyone believes global warming is real, or even knows if it’s happening. Some even think it’s not something to worry about at all.
To truly understand global warming or the issue of rising global temperatures, we must first understand the relationship between climate and weather.
2.
Weather
and Climate
Weather is local and temporary. If it snows in your city next Tuesday, that’s the weather at that moment for your city. Climate, on the other hand, refers to long-term characteristics and is not related to a small area. The long-term average weather in a region is called the climate of that specific place. For example, if the place you live has very cold winters and lots of snow, that’s a characteristic of that region’s climate. If historically, every winter has been cold with snowfall, it’s reasonable to expect similar weather in future winters as well.
When talking about climate, “long-term” really does mean a very long time. In the context of climate, even hundreds of years are considered a very short span. In fact, climate change typically takes more than ten thousand years. This means that if for one, two, or three consecutive years winters are less cold, that doesn’t mean the climate is changing. This should just be considered an exception, because while it’s a bit different from the norm, it does not indicate a permanent change.
Image: Average temperature from December to February in the United States between 1895–2005, indicating the region’s climate [ Courtesy of NOAA ]
It’s also important to know that even a slight change in climate can have a significant impact. When scientists talk about the Ice Age, they mean weather conditions so cold that everything was covered with ice. In reality, during the last Ice Age (which occurred roughly every 50,000 to 100,000 years), the Earth’s average temperature was only 5°C lower than it is now, yet it was much colder overall [Source].
Global warming is a significant rise in the Earth’s average climate temperature over a relatively short period, mainly due to human activities. More specifically, if the Earth’s average climate temperature rises by 1 degree or more over one to two hundred years, this could be called global warming. Even a rise of 0.4 degrees in a hundred years is considerable.
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Natural Climate Change Naturally, it takes thousands of years for the Earth’s temperature to change by just one degree, whether hotter or colder. This is normal. Besides the recurring Ice Ages, other factors can cause climate changes, such as volcanic activity, changes in the planet’s plant cover, variation in solar radiation, and natural chemical changes in the atmosphere. |
3.
The Greenhouse Effect
The increase in the greenhouse effect is causing global warming to rise. However, the greenhouse effect is not inherently a bad thing; it’s necessary for maintaining the heat needed for life to exist on Earth by trapping warmth in the atmosphere.
Here’s a simple example to explain the greenhouse effect. If you leave a car parked in the sun with the windows closed, you’ll notice that the inside gets much hotter than the outside after a while. First, sunlight enters the car through the windows. Then, the seats, floor mats, and dashboard absorb some of that heat and become warm. When these items release heat, not all of it escapes through the windows; some gets trapped inside, because the wavelength of sunlight is different from the wavelength of the heat emitted by the seats and such. As a result, less heat is able to escape than enters, causing the interior to become increasingly hot.
Image: Simple illustration of the greenhouse effect [Courtesy: U.S. Global Change Research Program]
About 70% of the sunlight entering the Earth’s atmosphere is absorbed by land, oceans, vegetation, and other surfaces. The remaining roughly 30% is reflected back into space by clouds, ice sheets, and other reflective surfaces [Source]. However, the 70% of energy that does get trapped is not held forever (if it were, the Earth would be a blazing inferno). Things that absorb the sun’s heat, like earth and water, re-emit it. Some of this re-emitted heat escapes into space, but some is reflected back down to Earth by atmospheric components like carbon dioxide, methane, or water vapor. The heat that can’t escape keeps our planet warmer than space, because less energy leaves than enters. This entire process—the greenhouse effect—is what keeps the Earth warm enough to support life.
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Earth Without the Greenhouse Effect
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4.
Global Warming: What is Happening?
Certain substances or gases that are naturally produced are responsible for the greenhouse effect. Unfortunately, since the Industrial Revolution, human activity has released these substances into the atmosphere in massive quantities.
Carbon dioxide (CO2) is a colorless gas produced by the combustion of organic matter. It makes up less than 0.04% of the Earth’s atmosphere, most of which originated from volcanic activity in the early history of our planet. Today, human activities are releasing vast amounts of CO2 into the atmosphere, increasing its overall concentration [Source]. This increase is considered the primary cause of global warming because carbon dioxide absorbs infrared radiation. Most of the energy escaping from Earth’s atmosphere is in this form, so extra CO2 means more energy is absorbed, raising the planet’s temperature.
Courtesy NASA
Image: Among the main sources of greenhouse gases like carbon dioxide and methane are power plants, cattle, and automobiles.
The Worldwatch Institute has reported that global carbon emissions increased from 1 billion tons in 1900 to 7 billion tons in 1995. The organization also noted that the Earth’s average temperature rose from 14.5°C in 1860 to 15.3°C in 1980.
NOAA, Dave Keeling, and Tim Whorf (Schipps Institution of Oceanography), courtesy:
Image: Carbon dioxide concentration as measured in Mauna Loa, Hawaii
Another important greenhouse gas is nitrous oxide (NO2). While human-caused NO2 emissions are far less than CO2, NO2 absorbs about 270 times more energy than CO2. Therefore, reducing NO2 emissions is also important in efforts to decrease greenhouse gases [Source]. Large amounts of nitrogen fertilizer used in agriculture create nitrous oxide, which then escapes into the atmosphere. Nitrous oxide is also a byproduct of combustion.
Methane is a flammable gas and the main component of natural gas. It is naturally formed through the decomposition of organic matter, and can also be released from wetlands. Human activities produce methane in several ways:
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Extracting from mines
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Livestock herds (digestive gases)
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Bacteria in rice paddies
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From decomposition in landfills.
Like carbon dioxide, methane also absorbs infrared energy, thus warming the planet. Some scientists believe that at one time, a massive methane release in the Earth’s atmosphere (possibly from large deposits frozen under the sea) caused a brief but intense episode of global warming resulting in the extinction of many species (Discover Magazine, December, 2003).
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Water vapor is the most abundant greenhouse gas, but it’s produced less by human activity and more as a result of climate change. Drops of water on the Earth’s surface absorb heat from the sun and nearby sources. When enough energy is absorbed, some molecules gain enough energy to escape into the air as vapor. As these vapor molecules rise, the air temperature drops, causing them to lose energy and turn back into liquid, eventually falling back to Earth’s surface and completing the water cycle. This is called a positive feedback loop. Water vapor is harder to quantify than other greenhouse gases and scientists are not entirely sure about its exact role in global warming. However, the NOAA site says this:
As the amount of water vapor in the atmosphere increases, more of it condenses into clouds, which can reflect more solar radiation back into space (reducing the energy reaching Earth’s surface and thus reducing warming)
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What could actually happen if the Earth warms by a few more degrees? To learn more, read the following sections.
5.
Impacts of Global Warming: Rising Sea Levels
We’ve already seen that a decrease in average global temperature of just 5°C over thousands of years could cause an Ice Age. So what could happen if the Earth’s temperature rises by several degrees over just a few hundred years? There is no clear answer to that. In fact, even short-term weather forecasts are rarely completely accurate, because weather is a complex phenomenon. For long-term climate forecasts, we have to make careful guesses based on our historical understanding of climate.
Photo courtesy of NASA
Image: Some possible consequences of global warming include low-lying islands being submerged due to rising sea levels, increased number and intensity of natural disasters, and the disappearance of glaciers and ice caps.
Glaciers and ice sheets in various parts of the world may begin to melt. In fact, this is already happening [Source]. As large ice-covered areas shrink, global warming can accelerate , because less solar energy is reflected from the Earth’s surface (as explained earlier). The immediate effect of melting glaciers is a rise in sea levels. At first, this increase might just be an inch or two (in fact, if Western Antarctica’s ice sheets melt, sea level could rise by up to 10 feet [Source], submerging many coastal regions). Additionally, as temperatures rise, seawater expands, further increasing sea levels. Even a small rise can cause flooding in low-lying coastal areas.
Earth Observatory, courtesy
Image: Research-based predictions indicate rising sea levels
As the overall temperature of the oceans increases, the number and strength of storms like tropical storms and hurricanes
will also increase, because these storms extract their immense destructive power by passing over warm ocean waters.
6.
Impacts of Global Warming: Nature and Ecosystems
If the Earth’s average temperature rises, the changes will be gradual. In temperate regions with four seasons, the growing season will last longer and rainfall will also increase, which could be beneficial in many ways. Conversely, colder regions are also expected to get warmer, but rainfall there may decrease unusually, leading to long-term droughts and desertification.
The impact on biological ecosystems 1 will be the greatest, and also the hardest to predict. Many ecosystems are incredibly complex and fragile; a minor change may cause some species to go extinct, and the loss of one species could impact others that depend on it. Most ecosystems are interconnected, so the total effect of these chain reactions is almost impossible to predict. One outcome could be that a forest gradually dries and turns into grassland, or an entire coral reef dies. Many plant and animal species will adapt, move elsewhere, or become extinct as the climate changes.
It’s difficult to estimate the full impact of global warming on human life. Every year, thousands of elderly and ill people die of heat stroke or other heat-related illnesses. The poor in developing countries are most vulnerable, as they often lack the financial resources to cope with heat-related problems. Reduced rainfall means lower crop yields and more people starving, while increased flooding in coastal areas leads to more water-borne diseases and potential fatalities.
Next, let’s see why some people remain unconcerned about global warming.
7.
Is Global Warming Really a Problem?
Some people simply do not believe that global warming is happening. There are several reasons for this:
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They believe there’s no observable trend in global temperature data due to insufficient or unclear long-term data.
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Some scientists think that people worried about global warming are misinterpreting or misanalyzing the data. In other words, instead of reviewing data objectively, they’re focusing only on evidence that supports global warming.
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Some say the observed global temperature increase is part of the natural climate cycle or is caused by something other than greenhouse gases.
Some scientists acknowledge that global warming is happening, but do not think it is at a worrisome level. They argue that the planet will naturally resist this scale of climate change, and our resistance is much greater than we think. Plants and animals will adapt, so catastrophic consequences are unlikely. They point out that longer growing seasons, changes in rainfall, and stronger weather events are not necessarily destructive. Another argument is that the economic costs of reducing greenhouse gas emissions would outweigh any economic losses caused by global warming.
So, what’s the real answer? It’s genuinely difficult to say. Most scientists will tell you that global warming is real and is causing some degree of harm, but there is still significant debate about the extent of the problem and what dangers it might bring.
In the next section, we’ll explore what we can do to prevent global warming.
8.
Can We Stop Global Warming?
There are several things we can do to stop global warming. Ultimately, it comes down to reducing the use of substances that produce greenhouse gases. On an individual level, you can help by using less energy. Most of the devices in our homes run on electricity, and most of the electricity that power plants produce comes from burning fossil fuels. Turn off lights when not needed. Use less hot water in the shower, or reduce your shower time. On hot days, use (electric) fans instead of air conditioners.
BMW AG, Munich, Germany; DOE/NREL; SunLine Transit Agency, courtesy
Image: Hydrogen-powered cars, increased use of solar cells, and hydropower plants are promising ways to reduce greenhouse gas emissions
Here are a few specific methods that can help you reduce greenhouse gas emissions:
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Make sure your car’s engine is well-tuned. This helps the car run more efficiently and produce less harmful gases.
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Walk, cycle, or use motorcycles whenever possible. Cars produce more greenhouse gases than anything else.
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Turn off unused lights and other devices. Although electric bulbs do not emit greenhouse gases, the electricity that powers them is usually generated in power plants that do.
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Recycle whenever possible. Unrecycled waste ends up in landfills, which emit methane; moreover, recycling uses less energy than producing goods from raw materials.
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Plant trees wherever you can. Plants absorb carbon dioxide from the air and release oxygen.
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Don’t burn trash. This releases carbon dioxide and other hydrocarbons into the air.
Cars that burn fossil fuels produce CO2;
smaller, more fuel-efficient vehicles emit less CO2, especially hybrids. Walk or cycle to work whenever possible or carpool with others.
To truly reduce greenhouse gas emissions, we need to develop alternative fuel sources to fossil fuels. Greater use of hydro–power,
solar energy,
hydrogen engines,
and fuel cells can play a major role in cutting greenhouse gases.
solar energy,
hydrogen engines,
and fuel cells can play a major role in cutting greenhouse gases.
Internationally, the Kyoto Protocol was formulated to reduce global CO2 and other greenhouse gas emissions. Thirty-five developed countries committed to reducing various amounts of their greenhouse gas emissions. Unfortunately, one of the world’s largest emitters, the United States, did not sign the agreement.
For more information on global warming and related topics, see the resources below.
9.
Further Resources
Relevant articles on HowStuffWorks
- How Catalytic Converters Work
- How Ecolodges Work
- Eden Project: How it Works
- How Electric Cars Work
- How Hybrid Cars Work
- How the Hydrogen Economy Works
- How Ozone Pollution Works
- How Rainforests Work
- How the World Wildlife Fund Works
More excellent resources
- New Scientist: Climate Change
- NPR: Three Views on Global Warming
- The EPA Global Warming Kids Page
- NOAA: Global Warming
- National Academy of Sciences: Global Warming Facts & Our Future
- Washington Post.com: Kyoto Treaty Takes Effect Today
– February 16, 2005
- English Wikipedia:
Rainforest - English Wikipedia: Kyoto Protocol
References
- Flavin,
Christopher and Tunali, Odil. Climate of Hope: New Strategies for
Stabilizing the World’s Atmosphere. Worldwatch Institute, 1996.
1-878071-32-7.
- Jones,
Laura, editor. Global Warming: The Science and the Politics. The
Fraser Institute, 1997. 0-88975-184-6.
- Singer,
S. Fred. Hot Talk, Cold Science: Global Warming’s Unfinished Debate.
The Independent Institute, 1998. 0-945999-78-x.
- Tesar,
Jenny. Global Warming. Facts On File, 1991. 0-8160-2490-1.
- The EPA Global Warming Kids Page
- Earth Observatory: Global Warming
- NOAA: Global Warming
1
Ecosystem: The reciprocal relationship and interactions between living organisms and the non-living world around them in nature
Ecosystem: The reciprocal relationship and interactions between living organisms and the non-living world around them in nature
শামীম ভাই যে অনেক কষ্ট ও সময় ব্যয় করে এই প্রবন্ধটি লিখেছে তা পড়েই বুঝা যাচ্ছে। এই ধরনের মৌলিক লেখার জন্য শামীম ভাই কে ধন্যবাদ।
ধ্রুব,
এটা অনুবাদ; মৌলিক লেখা, তবে আমার নয়। অন্য আরেকজনের মৌলিক লেখা। মূল লেখার যোগসূত্র একেবারে প্রথমেই উল্লেখ করেছি (পি.ডি.এফ. হিসেবে দেখুন এর ঠিক নিচেই; ক্লিক করে দেখুন)।
একথা সত্য যে প্রবন্ধটি করতে অনেক সময় ব্যয় হয়েছে, কিন্তু যখনই ভেবেছি বাংলায় থাকার ফলে অনেকে এটা পড়ে উপকৃত হবেন তখনই মনটা আনন্দে ভরে গেছে, নতুন উদ্যমে শুরু করেছি। আর করেছি ওপেন অফিস রাইটার ব্যবহার আর অভ্র কি-বোর্ড ব্যবহার করে (দুটিই ফ্রী-ওয়্যার)। ওপেন অফিস বেশিদিন ধরে ব্যবহার করছি না, তাই ফরম্যাটিংটায় স্বাভাবিকের চেয়ে সময় বেশি লেগেছে। কিন্তু এর পর থেকে ফরম্যাটিং করতে সময় লাগবে না… হাত পাকায় ফেললাম। পরিভাষা জ্ঞানের অভাবটা বেশ অনুভব করেছি।
দেশে গেলেও এটার প্রিন্ট কপি (পি.ডি.এফ. থেকে) কিছু লোককে দেব; বিশেষত গ্রামে থেকে যারা অত্যন্ত আগ্রহের সাথে নিউজপেপার পড়েন; আর এসকল ব্যাপারে প্রশ্ন করেন। আর দেব পরিচিত কিছু বিদ্যালয়ের শিক্ষককে – কারণ সচেতনতা বৃদ্ধি খুব জরুরী।
পরিশেষে, আপনার মন্তব্যের জন্য ধন্যবাদ।
মিয়া মোহাম্মদ হুসাইনুজ্জামান লিখেছেন এটা তাঁর মৌলিক রচনা নয়, অনুবাদ যেহেতু বিষয়টি বিশ্বউষ্ণায়ন তাই লেখাটিতে কেবল সে দিকটিই দেখা হয়েছে, আশেপাশের কিছু বিবেচনা করা হয়নি বিশ্বউষ্ণায়ন ঠেকাতে গাছ লাগাতে বলা হয়েছে, কিন্থু গাছ লাগাবার জমি থাকলে তো? মানুষ নাকি অদূর ভবিষ্যতে কেবল হাঁটবার মতো জায়গা পাবে, তখন খাদ্য বস্ত্র বাসস্থান চিকিৎসা ইত্যাদির কী হবে? সিডারের সাড়ে পাঁচ মাস পরে নার্গিস হয়েছে, এর পর তো সপ্তাহে সপ্তাহে তা হবে, তখন কী করা যাবে? সবচেয়ে সহজ পথ হল, বিশ্বের জনসংখ্যা কমাতে হবে, এবং তৎপ্রতিক্রিয়ায় শিল্পোৎপাদনও কমবে, নইলে বিপদ কমতে পারে না বিশ্বউষ্ণায়ন নিয়ে বিপরীত কথা বলার সূত্রটি সম্ভবত এই যে, “গ্রীনহাউজ গ্যাস নির্গমণ কমানোর উদ্যোগের ফলে মানুষের উপর যে অর্থনৈতিক চাপ পড়বে, তা বৈশ্বিক উষ্ণায়ণের ফলে সৃষ্ট অর্থনৈতিক ক্ষতির চেয়ে অনেক বেশি।” অর্থাৎ দৃষ্টিটা অর্থনৈতিক কোণ থেকে নিয়ন্ত্রিত মানুষ বাঁচলে তো “অর্থনৈতিক ক্ষতির” কথা উঠতে পারে মায়ানমারে দশ হাজার মৃত(৬মে-২০০৮) আরও ভয়াবহ খবর তো অপেক্ষা করছে
মনোজকুমার দ. গিরিশ ০৬/০৫/২০০৮ কোলকাতা
I want title of global warming,thankful of global warming, object of global warming, meaning of global warming and decision of global warming in Bengali language.