环保作文素材http://www.xiezu.com/li/suocai/18714.html
1、全球变暖与城市“热岛”
全球变暖会引起世界各地区降水与干湿状况的变化,进而导致世界各国经济结构的变化。中纬度地区将会因气候变暖使蒸发强烈而变得干旱,现在农业发达的地区将退化成草原;高纬度地区则会因变暖而增加降水,温带作物将可以在此安家。但就全球来看,气候变暖对世界经济的负面影响是主要的,得到好处的仅是局部某些地区。
城市的气温比近郊要高得多,犹如一座温暖的岛屿。我国最大的城市“热岛”北京,比郊区温度高出9.6度,上海与郊区的最大温差也达6.8度。造成城市“热岛”效应的原因在于城市人口集中并不断增多,工业发达,居民生活、工业生产和汽车等交通工具每天要消耗大量的煤、石油、天然气等燃料,释放出大量的人为热。还有一个原因是城市中由混凝土、石料、砖瓦堆砌成的建筑群与柏油、水泥、陶瓷、石料等铺设的路面、人行道、广场,代替了原为植被、作物覆盖的自然地面。它们反射率小,热容量高,大量吸收太阳能。
2、物种迅速灭绝
由于人类活动的影响,尤其是人们乱伐森林、滥垦草原,以及环境污染,造成了野生
动植物栖息地或生长地的丧失和生活环境的恶化,再加上人们滥捕滥猎野生动物,使世界上许多种野生动植物已经灭绝或濒临灭绝。
国际保护自然联盟1996年发表的濒危物种《红色警报名单》显示,世界现存4500种哺乳动物中,面临绝种的已占24%,而现存约9500种鸟类中,有12%即将灭绝。在已知的大约1万种木本植物中,濒临绝种的约占6%,其中1000种左右危在旦夕。每24小时就有150~200种生物物种永远告别地球,据资料表明,目前地球上物种灭绝的速度比形成的速度快100万倍。中国是野生动植物十分丰富的国家,但是,中国生物的多样性正面临严重的威胁。被子植物中,濒危种有1000种,极危种28种;裸子植物濒危种63种,极危种14种,已有1种灭绝;脊椎动物受威胁的有433种。
3、世界水资源严重不足
随着世界人口的急剧增长,用水量不断增加,加上水污染日益严重,使许多本来可以
利用的淡水资源遭到破坏。目前世界上60%的地区面临供水不足,已有20%的人口难以得到清洁水,50%的人口无法得到卫生用水。许多国家用水紧张,近年来美国、日本及东欧许多国家都出现了水资源不足的问题,甚至连淡水资源比较丰富的俄罗斯与加拿大,有些地区也受到缺水的威胁。非洲的一些国家连年干旱,缺水直接威胁着人们的生存。有人预计,水危机将成为21世纪城市里“最容易引起争端的问题”。
4、环境问题的全球性
环境问题不仅是某个国家或某个区域的问题,目前已经发展成全球性的问题了。一个地区发生环境问题,影响的范围往往会大大超过该地区。例如,酸雨随着大气的运动,能影响到很远的地区;国际性河流上游被污染,将使河流全流域遭受影响……环境污染问题日益严重,废气、废水甚至固体废弃物都可以从一国转移到另一国。有些环境问题甚至影响着全人类的生存与发展。例如,亚马孙河流域热带雨林的破坏,会对全球的气候产生影响;大气中CO2浓度的升高和臭氧层的破坏,更是威胁着全人类。
5、我国的资源状况
从自然资源总量讲,我国许多种自然资源的总量都在世界前列,称得上是地大物博的
资源大国。但我国人口众多,各类资源的人均占有量都是很少的。人均资源相对不足,是我国资源方面的基本国情。
我国耕地面积居世界第四位,人均耕地占有量却只相当于世界人均值的1/3;森林面积居世界第六位,人均森林占有量只相当于世界人均值的1/5;我国矿产资源储量总值居世界第三位,人均占有量相当世界人均值的3/5……而且随着我国人口持续增多,各种资源的人均占有量还会继续下降。人均资源相对不足,已成为我国经济发展与人民生活水平提高的制约性因素。我国的资源还存在地区分布不均衡的特点。例如我国水资源南方多、北方少,耕地资源却南方少、北方多,很不利于农业的发展。
6、大气污染
科学家发现,至少有100种大气污染物对环境产生危害,其中对人体健康危害较大的
有二氧化硫、氮氧化合物、一氧化碳、氟氢烃等。大气污染物严重危害
环保作文(原创)
http://218.4.203.36/oblog31/user1/264/archives/2006/13848.html
一个晴空万里的早晨,我还在同周爷爷谈天说地。忽然,一位老人出现在我面前,语重心长的对我说:“可可,你是未来的希望。 我告诉你,地球已经遭到到严重破坏,你得尽快地救救他,不然后果不堪设想!”说完,便把他手中的拐杖转了一圈,嘴里念这谁也听不懂的咒语,然后轻轻地想我一指。霎时,我身上奇迹般的穿上了一件金衣,手里也出现了一只魔杖。平时总梦想着当巾帼英雄的我终于如愿以偿,觉得自己神气极了、帅极了。
“好,老爷爷,我一定不辜负您的期望。”我胸有成竹的对老人说。
老人听后,面带微笑的消失了。我飞到地球上空,俯视着被严重破坏了的地球,目瞪口呆:只见那“母亲河”以北废物堵塞的水泄不通,原来那清澈见底的河水不知被谁“下了毒药”,斯鱼成群;闹喧闹的街道成了泥泞小路;那一袋袋垃圾引来了一群群老鼠和不计其数的苍蝇发出一阵阵令人恶心的臭味;远处那些工厂只顾生产,毫无顾忌地把乌烟、废气排放到空中,使那些雪白的云朵渐渐成了“乌云”……
望着眼前的景象,我立刻拿起魔杖,学着老人的样子,向地面轻轻一指。只见小河立即恢复原样,静静的流淌着;那泥泞的街道,马上变成了宽阔而平坦的水泥大道;工厂也停止了排放废气……望着眼前如此宁静的世界,我满心欢喜的离开了……
Now more and more people are focusing on the nature. It is no doubt that the nature is important to every human being. No nature, no life. Because of the supplies of the nature, we have lived happily for a long time. And we started to gain every thing available from the nature. And this lasted so long a time. Today, people have discovered that the nature around is getting worse and worse.
What is threatening the nature? Air and water pollution, overharvesting of plant and animal species, overpopulation and so on. Overpopulation is the biggest source of pollution. Let's take overpopulation as an example.
What does overpopulation feel like? When we move slowly through the city in a tazi. When we enter a crowded slum district. When the temperature is high and when the air is thick with dust and smoke. The streets are crowded with people. The streets seem alive with people. People eating. People washing. People talking. People sleeping. People visiting each other, arguing and screaming. People relieving themselves. People pushing their hands through the taxi windows, begging. People leading animals. People, people, people, people. As we drive slowly through the crowd, sounding the taxi's horn, the dust, heat, noise and cooking fires made it like a scene from hell! I admit, frightening.
To the nature, overpopulation is a big problem. More people, more pollution. And the big population is threatening the nature every second.
the rapid rise in world population is not creating problems only for the developing countries. The whole world faces the problem that raw materials are being used up at an increasing rate and food production can not keep up with the population increase. People in rich countries make the heaviest demands on the world's resources, its food, fuel and land, and cause the most pollution. A baby born in the United States will use in his lifetime 30 times more of the world's resources than a baby born in India. Unless all the countries of the world take united action to deal with the population explosion there will be more and more people fighting for a share of less and less land, food and fuel, and the future will bring poverty, misery and war to us all.
For most of the developing countries, it is a good idea to control the population growth. For example, China has carried out birth control for years. And this plan has a GREat effect on the world population.
If the population continues to increase, if the air and water continue to be polluted, if we don't do something to protect wild-plant and wildlife species will be declining. Species and biological communities have difficulty adapting to change. Economic opportunities and the quality of life of future generations are also put at risk. By protecting nature, we protect ourselves.
Let's unite together, hand in hand we stand all across the land.
We can make this world in which to live. Hand in hand. Control the population growth. Take good care of our nature.