What do we know about climate change?
December 21st, 2009Climate change has long-since ceased to be a scientific curiosity, and is no longer just one of many environmental and regulatory concerns. As the United Nations Secretary General has said, it is the major, overriding environmental issue of our time, and the single greatest challenge facing environmental regulators. It is a growing crisis with economic, health and safety, food production, security, and other dimensions.
Climate change is a change in the statistical distribution of weather over periods of time that range from decades to millions of years. It can be a change in the average weather or a change in the distribution of weather events around an average (for example, greater or fewer extreme weather events). Climate change may be limited to a specific region, or may occur across the whole Earth.
In recent usage, especially in the context of environmental policy, climate change usually refers to changes in modern climate. It may be qualified as anthropogenic climate change, more generally known as global warming.
Factors that can shape climate are climate forcing. These include such processes as variations in solar radiation, deviations in the Earth’s orbit, mountain-building and continental drift, and changes in greenhouse gas concentrations. There are a variety of climate change feedbacks that can either amplify or diminish the initial forcing. Some parts of the climate system, such as the oceans and ice caps, respond slowly in reaction to climate forcing because of their large mass. Therefore, the climate system can take centuries or longer to fully respond to new external forcing.
Shifting weather patterns, for example, threaten food production through increased unpredictability of precipitation, rising sea levels contaminate coastal freshwater reserves and increase the risk of catastrophic flooding, and a warming atmosphere aids the pole-ward spread of pests and diseases once limited to the tropics.
The news to date is bad and getting worse. Ice-loss from glaciers and ice sheets has continued, leading, for example, to the second straight year with an ice-free passage through Canada’s Arctic islands, and accelerating rates of ice-loss from ice sheets in Greenland and Antarctica. Combined with thermal expansion—warm water occupies more volume than cold—the melting of ice sheets and glaciers around the world is contributing to rates and an ultimate extent of sea-level rise that could far outstrip those anticipated in the most recent global scientific assessment.
There is alarming evidence that important tipping points, leading to irreversible changes in major ecosystems and the planetary climate system, may already have been reached or passed. Ecosystems as diverse as the Amazon rainforest and the Arctic tundra, for example, may be approaching thresholds of dramatic change through warming and drying. Mountain glaciers are in alarming retreat and the downstream effects of reduced water supply in the driest months will have repercussions that transcend generations. Climate feedback systems and environmental cumulative effects are building across Earth systems demonstrating behaviours we cannot anticipate.
The potential for runaway greenhouse warming is real and has never been more present. The most dangerous climate changes may still be avoided if we transform our hydrocarbon based energy systems and if we initiate rational and adequately financed adaptation programmes to forestall disasters and migrations at unprecedented scales. The tools are available, but they must be applied immediately and aggressively.
Human activities that contribute to climate change include in particular the burning of fossil fuels, agriculture and land-use changes like deforestation. These cause emissions of carbon dioxide (CO2), the main gas responsible for climate change, as well as of other ‘greenhouse’ gases. To bring climate change to a halt, global greenhouse gas emissions must be reduced significantly.
If things go on pretty much as they have been, scientists’ best guess is that the amount of warming will be about 2.5°F (1.4°C) by the year 2050. The range of uncertainty stretches from almost no change to over 4°F (2.3°C).
The ozone hole is a different problem, Many people confuse the hole in the ozone layer with climate change. However, these two problems are not closely related. The ozone layer protects the earth from harmful ultraviolet light that can cause skin cancer and damage plants and animals. The main cause of the hole in the ozone layer is chlorofluorocarbons (CFCs), gases that are used in refrigerators, air conditioners, and industrial applications. While CFCs alone cause warming, their ozone destruction can cause cooling.
When the weather gets warmer, evaporation from both land and sea increases. This can cause drought in areas of the world where the increased evaporation is not compensated for by more precipitation. The extra water vapor in the atmosphere has to fall again as extra precipitation, which can cause flooding other places in the world. This will result of:
Less ice and snow:
Glaciers are shrinking rapidly at present. . In areas that are dependent on melt water from mountain areas, this can cause drought and a lack of drinking water.
More extreme weather incidents:
The warmer climate will most probably cause more heatwaves, more cases of heavy rainfall and also possibly an increase in the number and/or severity of storms.
Rising sea level:
The sea level rises for two reasons. Partly because of the melting ice and snow, and partly because of the thermal expansion of the sea. Thermal expansion takes a long time, but even an increase in temperature of two degrees Celsius is expected, in due time, to cause a rise in the water level of almost a metre.
During this month Copenhagen climate change conference took place so the leading countries in the world can find solution to the climate changes, The193-nation UN conference ended with delegates simply “taking note” of a US-led climate deal that recognised the need to limit temperature rises to 2C. a decision to which is far from the legally binding treaty which some had expected and for which many hoped.
Refrencess:
1-http://www.unep.org/climatechange
2-http://en.wikipedia.org/wiki/Climate_change
3-BBC world news. climate conferences coverage
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Climate change is one of the defining issues of our time. In order to tackle a problem of such massive proportions, we will need nothing less than a new ideological framework based on common sense notions. Instead of worrying just about ourselves, we will have no choice but to worry about one another. It will require a new type of thinking, one that was sorely lacking at Copenhagen, which was a total failure as far as I can tell.
If we act wisely, which is a big “if,” we will use the threat of climate change to come together in common purpose, and we will use environmental protection as an engine for economic growth, by which we protect the environment, grow our economies, and create good paying green jobs, all at the same time. Global Warming is the Grand Puppeteer’s way of giving us a swift kick in the ass, and forcing us to begin making sense of our lives.
sure nissim can not agree with you more ,we need to change our way of thinking and look to the whole picture of our life and fat
I agree Wamith. But the “whole picture” can be a bit scary to look at.
We lived as hunter/gatherers for some two million years. It wasn’t much of a life, but it was a life nonetheless. We survived, which is probably a lot easier said than done. This whole modernity thing is only a spec in time. The Industrial Revolution took place only 150 years ago. This globalization thing is only about 20 years old. That’s nothing in terms of how long we’ve been here on this good earth.
The basic question is: What if some ery basic assumptions are all wrong? What if our sense of “progress”is grossly misguided? We believe
Maybe its wrong to run our economies on fossil fuels?
Maybe its wrong to do whatever it takes for the sake of the “bottom line.”
Maybe the amount of money we have is not as important as our quality of life?
99% of all species on earth have become extinct. If we want to survive as a species; if we want to beat the odds, so to speak, maybe we have to look at how we survived some two million years.
Many of us assume that the brutishness and violence we see swirling around us dates back to the brutishness of the cavemen. Actually, many of us are wrong. It turns out that the cavemen were actually quite kind to one another. They took care of each other, and shared what they had. There is a movie on the Discovery Channel called The Rise of Man, which makes the point. In one scene a bunch of cavemen were hanging out in there cave, with plenty of food. A strange clan showed up, who were hungry and desperate. Would they fight one another for the food and the shelter? No. The comfortable clan took them in, and increased their gene pool for the sake of procreation.
Maybe we have to find a way to go back to the logic of the cavemen, even as we search for our creature comforts?