I have not posted anything this past couple of months cos i have been very busy with my studies...but since i have miss some important issues and some people think that my blog is informative i thought i have some spare time in my sleaves why not write another entry so here it is. First Merry Chritsmas to everyone and avance Happy New Year.
If you have seen the movie 2012 you might have been curious if that movie would come to life and if the end of our world is near. If you have seen all the things that happened in the movie all the signs and all the premonition you might be wondering could that really happen? could some of us really survive this kind of tragedy? The signs in the movie is close to what kind of nature's strike happend to us most of this is caused by the climate change. Let me give you some explination of what climate change is, what it could do to our planet and what is happening now due to it.
according to the National Academy of Sciences, "the phrase 'climate change' is growing in preferred use to 'global warming' because it helps convey that there are [other] changes in addition to rising temperatures."
Climate change refers to any significant change in measures of climate (such as temperature, precipitation, or wind) lasting for an extended period (decades or longer). Climate change may result from:
natural factors, such as changes in the sun's intensity or slow changes in the Earth's orbit around the sun;
natural processes within the climate system (e.g. changes in ocean circulation);
human activities that change the atmosphere's composition (e.g. through burning fossil)
The greenhouse effect is very important when we talk about climate change as it relates to the gases which keep the Earth warm. It is the extra greenhouse gases which humans have released which are thought to pose the strongest threat.
Impacts
Scientists in the
However, the next stage of that work, which is just as important, is looking at the knock-on effects of potential changes.
Water is an enormous consideration. As we are likely to see an increase in precipitation and sea level rises, does that mean an increase in flooding? What can we do to protect ourselves from that and how will it affect us financially?
Also, how will our health be affected by global warming, how will agricultural practices change, how will wildlife cope and what will the effects on coral be?
As for opportunities, well there will certainly be some positives of climate change as well as negatives so it is worth us considering those too.
Adaptation
The list of things we need to think about which will be affected by climate change is endless. In this section we give you a few examples of how we will need to change the way we live in order to cope with changes to our climate.
The regular use of renewable energy is becoming increasingly popular. Have a look at the possibilities for alternative energy sources, including solar power, wind power, geothermal, water power and even nuclear energy.
Play our game - I'm alright Jack - to influence his environment. You get to make choices at several stages in his life and can even decide how his house should be built.
What else can you do to help adapt to climate change and what can you do to help slow it down? There are many things we can all do at home. There are a host of ideas in Life at Home.
Buildings in the south east of the
The Earth's climate has changed throughout history. Just in the last 650,000 years there have been seven cycles of glacial advance and retreat, with the abrupt end of the last ice age about seven thousand years ago, marking the beginning of the modern climate era —and of human civilization. Most of these changes are attributed to the very small changes in the Earth’s orbit changing the amount of solar energy the Earth receives.
"Scientific evidence for warming of the climate system is unequivocal."
- Intergovernmental Panel on Climate Change
The current warming trend is of particular significance because most of it is very likely human-induced and proceeding at a rate that is unprecedented in the past 1,300 years.1
Earth-orbiting satellites and other technological advances have enabled scientists to see the big picture, collecting many different types of information about our planet and its climate on a global scale. Studying these climate data collected over many years reveal the signals of a changing climate.
Certain facts about Earth's climate are not in dispute:
The heat-trapping nature of carbon dioxide and other gases was demonstrated in the mid-19th century.2 Their ability to affect the transfer of infrared energy through the atmosphere is the scientific basis of many JPL-designed instruments, such as AIRS. Increased levels of greenhouse gases must cause the Earth to warm in response.
Ice cores drawn from Greenland,
The evidence for abrupt climate change is compelling:
Aitutaki atoll: Vulnerable to rising sea levels Global sea level rose about 17 centimeters (6.7 inches) in the last century. In the last decade, however, the rate of rise nearly doubled.3
The Keeling Curve shows a pattern of steadily increasing carbon dioxide in the atmosphere since 1958.
Levels of Carbon Dioxide are higher today than at anytime in past 650,000 years.
Scientists reconstruct past climate conditions through evidence preserved in tree rings, coral reefs and ice cores. For example, ice cores removed from 2 miles deep in the Antarctic contain atmospheric samples trapped in tiny air bubbles that date as far back as 650,000 years. These samples have allowed scientists to construct a historical record of greenhouse gas concentration stretching back hundreds of thousands of years.
The effects of climate change will likely include more frequent droughts in some areas and heavier precipitation in others. Global surface air temperatures rose three-quarters of a degree Celsius (almost one and a half degrees Fahrenheit) in the last century, but at twice that amount in the past 50 years. Eleven of the last 12 years (1995-2006) are the warmest since accurate recordkeeping began in 1850.4
The oceans have absorbed much of this increased heat, with the top 700 meters (about 2,300 feet) of ocean showing warming of 0.18 degrees Fahrenheit since 1955.
Flowing meltwater from the Greenland ice sheet The
The disappearing snowcap of
Many species of plants and animals are already responding to global warming, moving to higher elevations or closer to the poles.
Precipitation and evaporation patterns over the oceans have changed, as evidenced by increased ocean salinity near the equator and decreased salinity at higher latitudes.6
Most scientists agree the main cause of the current global warming trend is human expansion of the "greenhouse effect" -- warming that results when the atmosphere traps heat radiating from Earth toward space.
Certain gases in the atmosphere behave like the glass on a greenhouse, allowing sunlight to enter, but blocking heat from escaping. Long-lived gases, remaining semi-permanently in the atmosphere, which do not respond physically or chemically to changes in temperature are described as "forcing" climate change whereas gases, such as water, which respond physically or chemically to changes in temperature are seen as "feedbacks."
Gases that contribute to the greenhouse effect include:
Water vapor. The most abundant greenhouse gas, but importantly, it acts as a feedback to the climate. Water vapor increases as the Earth's atmosphere warms, but so does the possibility of clouds and precipitation, making these some of the most important feedback mechanisms to the greenhouse effect.
Carbon dioxide (CO2). A minor but very important component of the atmosphere, carbon dioxide is released through natural processes such as respiration and volcano eruptions and through human activities such as deforestation, land use changes, and burning fossil fuels. Humans have increased atmospheric CO2 concentration by a third since the Industrial Revolution began. This is the most important long-lived "forcing" of climate change.
Methane. A hydrocarbon gas produced both through natural sources and human activities, including the decomposition of wastes in landfills, agriculture, and especially rice cultivation, as well as ruminant digestion and manure management associated with domestic livestock. On a molecule-for-molecule basis, methane is a far more active greenhouse gas than carbon dioxide, but also one which is much less abundant in the atmosphere.
Nitrous oxide. A powerful greenhouse gas produced by soil cultivation practices, especially the use of commercial and organic fertilizers, fossil fuel combustion, nitric acid production, and biomass burning.
Chlorofluorocarbons (CFCs). Synthetic compounds of entirely of industrial origin used in a number of applications, but now largely regulated in production and release to the atmosphere by international agreement for their ability to contribute to destruction of the ozone layer. They are also greenhouse gases .
Not enough greenhouse effect: The planet Mars has a very thin atmosphere, nearly all carbon dioxide. Because of the low atmospheric pressure, and with little to no methane or water vapor to reinforce the weak greenhouse effect, Mars has a largely frozen surface that shows no evidence of life.
Too much greenhouse effect: The atmosphere of Venus, like Mars, is nearly all carbon dioxide. But Venus has about 300 times as much carbon dioxide in its atmosphere as Earth and Mars do, producing a runaway greenhouse effect and a surface temperature hot enough to melt lead.
On Earth, human activities are changing the natural greenhouse. Over the last century the burning of fossil fuels like coal and oil has increased the concentration of atmospheric carbon dioxide (CO2). This happens because the coal or oil burning process combines carbon with oxygen in the air to make CO2. To a lesser extent, the clearing of land for agriculture, industry, and other human activities have increased concentrations of greenhouse gases.
The consequences of changing the natural atmospheric greenhouse are difficult to predict, but certain effects seem likely:
On average, Earth will become warmer. Some regions may welcome warmer temperatures, but others may not.
Warmer conditions will probably lead to more evaporation and precipitation overall, but individual regions will vary, some becoming wetter and others dryer.
A stronger greenhouse effect will warm the oceans and partially melt glaciers and other ice, increasing sea level. Ocean water also will expand if it warms, contributing further to sea level rise.
Meanwhile, some crops and other plants may respond favorably to increased atmospheric CO2, growing more vigorously and using water more efficiently. At the same time, higher temperatures and shifting climate patterns may change the areas where crops grow best and affect the makeup of natural plant communities.
The role of human activity
In its recently released Fourth Assessment Report, the Intergovernmental Panel on Climate Change, a group of 1,300 independent scientific experts from countries all over the world under the auspices of the United Nations, concluded there's a more than 90 percent probability that human activities over the past 250 years have warmed our planet.
The industrial activities that our modern civilization depends upon have raised atmospheric carbon dioxide levels from 280 parts per million to 379 parts per million in the last 150 years. The panel also concluded there's a better than 90 percent probability that human-produced greenhouse gases such as carbon dioxide, methane and nitrous oxide have caused much of the observed increase in Earth's temperatures over the past 50 years.
They said the rate of increase in global warming due to these gases is very likely to be unprecedented within the past 10,000 years or more. The panel's full Summary for Policymakers report is online at http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr_spm.pdf.
Solar irradiance
It's reasonable to assume that changes in the sun's energy output would cause the climate to change, since the sun is the fundamental source of energy that drives our climate system.
Indeed, studies show that solar variability has played a role in past climate changes. For example, a decrease in solar activity is thought to have triggered the Little Ice Age between approximately 1650 and 1850, when Greenland was largely cut off by ice from 1410 to the 1720s and glaciers advanced in the
But several lines of evidence show that current global warming cannot be explained by changes in energy from the sun:
Since 1750, the average amount of energy coming from the Sun either remained constant or increased slightly.
If the warming were caused by a more active sun, then scientists would expect to see warmer temperatures in all layers of the atmosphere. Instead, they have observed a cooling in the upper atmosphere, and a warming at the surface and in the lower parts of the atmosphere. That's because greenhouse gasses are trapping heat in the lower atmosphere.
Climate models that include solar irradiance changes can’t reproduce the observed temperature trend over the past century or more without including a rise in greenhouse gases.
The current and future consequences of global change
The potential future effects of global climate change include more frequent wildfires, longer periods of drought in some regions and an increase in the number, duration and intensity of tropical storms.
Global climate change has already had observable effects on the environment. Glaciers have shrunk, ice on rivers and lakes is breaking up earlier, plant and animal ranges have shifted and trees are flowering sooner.
Effects that scientists had predicted in the past would result from global climate change are now occurring: loss of sea ice, accelerated sea level rise and longer, more intense heat waves.
"Taken as a whole, the range of published evidence indicates that the net damage costs of climate change are likely to be significant and to increase over time."
- Intergovernmental Panel on Climate Change
Scientists have high confidence that global temperatures will continue to rise for decades to come, largely due to greenhouse gasses produced by human activities. The Intergovernmental Panel on Climate Change (IPCC), which includes more than 1,300 scientists from the
According to the IPCC, the extent of climate change effects on individual regions will vary over time and with the ability of different societal and environmental systems to mitigate or adapt to change.
The IPCC predicts that increases in global mean temperature of less than 1.8 to 5.4 degrees Fahrenheit (1 to 3 degrees Celsius) above 1990 levels will produce beneficial impacts in some regions and harmful ones in others. Net annual costs will increase over time as global temperatures increase.
"Taken as a whole," the IPCC states, "the range of published evidence indicates that the net damage costs of climate change are likely to be significant and to increase over time."
Below are some of the regional impacts of global change forecast by the IPCC:
Latin America: Gradual replacement of tropical forest by savannah in eastern
Europe: Increased risk of inland flash floods; more frequent coastal flooding and increased erosion from storms and sea level rise; glacial retreat in mountainous areas; reduced snow cover and winter tourism; extensive species losses; reductions of crop productivity in southern
Africa: By 2020, between 75 and 250 million people are projected to be exposed to increased water stress; yields from rain-fed agriculture could be reduced by up to 50 percent in some regions by 2020; agricultural production, including access to food, may be severely compromised.
Asia: Freshwater availability projected to decrease in Central, South, East and
Global Climate Change: Recent ImpactsPhenomena Likelihood that trend occurred in late 20th century
Cold days, cold nights, frost less frequent over land areas Very likely
More frequent hot days and nights Very likely
Heat waves more frequent over most land areas Likely
Increased incidence of extreme high sea level * Likely
Global area affected by drought has increased (since 1970s) Likely in some regions
More frequent heat waves over most land areas Likely
Increase in intense tropical cyclone activity in
* Excluding tsunamis, which are not due to climate change.
Global Climate Change: Future TrendsPhenomena Likelihood of trend
Contraction of snow cover areas, increased thaw in permafrost regions, decrease in sea ice extent Virtually certain
Increased frequency of hot extremes, heat waves and heavy precipitation Very likely to occur
Increase in tropical cyclone intensity Likely to occur
Precipitation increases in high latitudes Very likely to occur
Precipitation decreases in subtropical land regions Very likely to occur
Decreased water resources in many semi-arid areas, including western
Definitions of likelihood ranges used to express the assessed probability of occurrence: virtually certain >99%, very likely >90%, likely >66%.
Unresolved questions about Earth's climate
Extreme Ultraviolet Imaging Telescope (EIT) image of the sun with a huge, handle-shaped prominence extending from it, taken in 1999. While there is no evidence of a change trend in solar output over the past half century, long-term changes in solar output are not well-understood.
This website presents a data-rich view of climate and a discussion of how many data sets fit together into scientists' current picture of our changing climate. But there's a great deal that we don't know about the future of Earth's climate and how climate change will affect humans
For convenience and clarity, climate scientists separate things that affect climate change into two categories: forcings and feedbacks (see sidebar at right).
Also, climate scientists often discuss "abrupt climate change," which includes the possibility of "tipping points" in the Earth's climate. Climate appears to have several states in which it is relatively stable over long periods of time. But when climate moves between those states, it can do so quickly (geologically speaking), in hundreds of years and even, in a handful of cases, in only a few decades. These rapid 'state changes' are what scientists mean by abrupt climate change. They are much more common at regional scales than at the global scale, but can be global. State changes have triggers, or "tipping points," that are related to feedback processes. In what's probably the single largest uncertainty in climate science, scientists don't have much confidence that they know what those triggers are.
Below is an explanation of just a few other important uncertainties about climate change, organized according to the categories forcing and feedback. This list isn't exhaustive. It is intended to illustrate the kinds of questions that scientists still ask about climate.
Forcings
Solar Irradiance. The sun has a well-known eleven-year irradiance cycle that produces a .08% variation in output.1 Solar irradiance has been measured by satellite daily since the late 1970s, and this known solar cycle is incorporated into climate models. There is some evidence from proxy measurements-sunspot counts going back centuries, measurements from ancient trees, and others-that solar output varies over longer periods of time, too. While there is currently no evidence of a trend in solar output over the past half century, because there are no direct observations of solar output prior to the 1970s, climate scientists do not have much confidence that they understand longer-term solar changes. A number of
Aerosols, dust, smoke, and soot. These come from both human and natural sources. They also have very different effects on climate. Sulfate aerosols, which result from burning coal, biomass, and volcanic eruptions, tend to cool the Earth. Increasing industrial emissions of sulfates is believed to have caused a cooling trend in the Northern Hemisphere from the 1940s to the 1970s. But other kinds of particles have the opposite effect. The global distribution of aerosols has only been tracked for about a decade from the ground and from satellites, but those measurements cannot yet reliably distinguish between types of particulates. So aerosol forcing is another substantial uncertainty in predictions of future climate.
Feedbacks
Clouds. Clouds have an enormous impact on Earth's climate, reflecting back into space about one third of the total amount of sunlight that hits the Earth's atmosphere. As the atmosphere warms, cloud patterns may change, altering the amount of sunlight absorbed by the Earth. Because clouds are such powerful climate actors, even small changes in average cloud amounts, locations, and type could speed warming, slow it, or even reverse it. Current climate models do not represent cloud physics well, so the Intergovernmental Panel on Climate Change has consistently rated clouds among its highest research priorities. NASA and its research partners in industry, academia, and other nations have a small flotilla of spacecraft and aircraft studying clouds and the closely related phenomenon of aerosols.
Carbon cycle. Currently, natural processes remove about half of each year's human carbon dioxide emissions from the atmosphere, although this varies a bit year to year. It isn't well understood where this carbon dioxide goes, with some evidence that the oceans are the major repository and other evidence that land biota absorbs the majority. There is also some evidence that the ability of the Earth system to continue absorbing it may decline as the world warms, leading to faster accumulation in the atmosphere. But this possibility isn't well understood either. The upcoming Orbiting Carbon Observatory mission will mark NASA's first attempt to answer some of these questions via space observations.
Ocean circulation. One very popular hypothesis about climate change is that as the Earth as a whole warms, ocean circulation in the Atlantic will change to produce cooling in
Precipitation. Human civilization is dependent upon where and when rain and snow fall. We need it for drinking water and for growing our food. Global climate models show that precipitation will generally increase, but not in all regions. Some regions will dry instead. Scientists and policymakers would like to use climate models to assess regional changes, but the models currently show wide variation in their results. For just one example, some models forecast less precipitation in the American southwest, where JPL is, while others foresee more precipitation. This lack of agreement on even the direction of change makes planning very difficult. There's much research to be done on this question.
Sea level rise. In its 2007 Fourth Assessment Report, the Intergovernmental Panel on Climate Change used new satellite data to conclude that shrinkage of ice sheets may contribute more to sea level rise than it had thought as recently as 2001. The panel concluded that it could not "provide a best estimate or an upper bound for sea level rise" over the next century due to their lack of knowledge about Earth's ice.2 There are 5-6 meters worth of sea level in the Greenland ice sheet, and 6-7 meters in the West Antarctic Ice Sheet, while the much larger East Antarctic Ice Sheet is probably not vulnerable to widespread melting in the next century. Many hundreds of millions of people live within that range of sea level increase, so our inability to predict what sea level rise is likely over the next century has substantial human and economic ramifications.
It is not NASA's role to develop solutions or public policies related to global climate change. Instead, the agency's mission is to provide the scientific data needed to understand climate change and to evaluate the impact of efforts to control it. (For more information, see NASA's role.)
The following selected resources from governmental organizations provide information about options for climate change mitigation.
This is what i have researched. If we dont act now our fear of the 2012 prediction will come to life. Soon we will have no planet to live in. If we care about it so much then why just say it why not act on it. You read what we can do to prevent this from happening and what we have done that caused this. Now we know so now we should do something to save our planet. You might think im being way over board in posting this things and that i am a little paranoid about the movie ( ok too much paranoid) but i just think that too much is enough and that 2012 might happen if we really dont act on it.
You all know that i have copied all the facts from other sites. So if you want more information visit the sites of my sources:
http://climate.jpl.nasa.gov/solutions/
http://www.epa.gov/climatechange/basicinfo.html
www.bbc.co.uk/climate
thank you for reading my blog..ill be more active now..promise... :)
1 comment:
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