The Greenhouse effect
Or, Global warming
To protect (রক্ষা করা) the trees from the cold air a special (বিশেষ) kind of house is built in cold countries. It is called green house. This house is generally (সাধারণত) made of glass. So sunlight (সূর্যালোক) can enter (প্রবেশ করা) the room. The house becomes hot with the rays (রশ্মি) of the sun but the hot air in the house cannot pass out (বেরিয়ে যাওয়া). In our air space (বায়ুমণ্ডল) carbon dioxide acts like a greenhouse. The increase (বৃদ্ধি) in global warming (উষ্ণতা is caused (ঘটা) by the increased (বর্ধিত) amount (পরিমাণ) of carbon dioxide around (চারদিকে) the earth (পৃথিবী). The green house effect is the cause (কারণ) of that global warming. Climatologists (জলবায়ু বিজ্ঞানী) predict (ভবিষ্যদ্বাণী করা) that midway (মাঝামাঝি) through this century (শতাব্দী) temperature (a) of the world may have risen by as much as four degree centigrade. This could destroy (ধ্বংস করা) wildlife (বন্যপ্রাণী) and wilderness (বনাঞ্চল), raise (বৃদ্ধি করা) sea levels (সমুদ্র স্তর) and thereby (সেই সূত্রে) flood (বন্যা কবলিত করা) coastal (উপকূলীয়) areas and farmlands (কৃষি জমি). As a result (ফলে) of the rise in sea level the southern (দক্ষিণ) part of the country may one day go under water. Deforestation (বন উজাড়করণ) is mainly (প্রধানত) responsible (দায়ী) for this problem. So, to avoid (পরিহার করা) this problem, we will have to plant (রোপন করা) more (অধিক) trees. If we fail get rid of the terrible consequences of global warming, our existence (অস্তিত্ব) will be in jeopardy.