Humans are the Cause of Global Warming
- Thread starter NorthStar
- Start date
And more people with ever larger carbon footprints. Not to mention the deforestation.
Just to stir the pot:
From The Washington Post
The Arctic Ocean is warming up, icebergs are growing scarcer and in some places the seals are finding the water too hot, according to a report to the Commerce Department yesterday from Consulafft, at Bergen, Norway
Reports from fishermen, seal hunters, and explorers all point to a radical change in climate conditions and hitherto unheard-of temperatures in the Arctic zone. Exploration expeditions report that scarcely any ice has been met as far north as 81 degrees 29 minutes.
Soundings to a depth of 3,100 meters showed the gulf stream still very warm. Great masses of ice have been replaced by moraines of earth and stones, the report continued, while at many points well known glaciers have entirely disappeared.
Very few seals and no white fish are found in the eastern Arctic, while vast shoals of herring and smelts which have never before ventured so far north, are being encountered in the old seal fishing grounds. Within a few years it is predicted that due to the ice melt the sea will rise and make most coastal cities uninhabitable.
Now see below.....................................
I apologize, I neglected to mention that this report was from November 2, 1922, as reported by the AP and published in The Washington Post 90+ years ago.
If you would care to check this out see http://www.snopes.com/politics/science/globalwarming1922.asp
From The Washington Post
The Arctic Ocean is warming up, icebergs are growing scarcer and in some places the seals are finding the water too hot, according to a report to the Commerce Department yesterday from Consulafft, at Bergen, Norway
Reports from fishermen, seal hunters, and explorers all point to a radical change in climate conditions and hitherto unheard-of temperatures in the Arctic zone. Exploration expeditions report that scarcely any ice has been met as far north as 81 degrees 29 minutes.
Soundings to a depth of 3,100 meters showed the gulf stream still very warm. Great masses of ice have been replaced by moraines of earth and stones, the report continued, while at many points well known glaciers have entirely disappeared.
Very few seals and no white fish are found in the eastern Arctic, while vast shoals of herring and smelts which have never before ventured so far north, are being encountered in the old seal fishing grounds. Within a few years it is predicted that due to the ice melt the sea will rise and make most coastal cities uninhabitable.
Now see below.....................................
I apologize, I neglected to mention that this report was from November 2, 1922, as reported by the AP and published in The Washington Post 90+ years ago.
If you would care to check this out see http://www.snopes.com/politics/science/globalwarming1922.asp
Oh but look again at post #39I don't know whether to laugh at its absurdity or cry that people actually believe that global warming is a conspiracy myth..
I don't believe that climate change is a 'conspiracy myth', nor I'm not a climate change 'denier', rather I am a climate change agnostic. The climate is always changing. The question is to what degree (pun intended) man's activities change the climate and what is the appropriate response. Clearly, one's political outlook informs their concern regarding climate change; with those who generally favor a more expansive government more sympathetic to a governmental response to climate data and visa versa.
If you are among those concerned about the deleterious effects of climate change, then there are a few fundamental questions that you should be able to answer:
1. If you are concerned about global warming, this implies a correct/optimal global temperature. What is it?
2. A scientific theory is only a theory if it can be disproved; otherwise it is an act of faith and not science. What data would disprove the null hypothesis regarding man made global warming?
3. If you believe that carbon dioxide is the cause of global warming, how do you explain the 17 year pause, not predicted by climate models? How do you account for other episodes of even warmer temperatures in the preindustrial age?
4. If humans are increasing global temperatures, is this a good or bad thing, i.e. are the net effects positive or negative? Why?
5. If a) humans are the cause of increased global temperatures and b) the net effect is negative; is it better to adapt to the changing climate or to disrupt modern civilization? Why?
6. Are there more immediate and fixable problems facing humanity based on simple, less speculative models? For example, we are facing an impending financial tsunami of debt related to unsustainable entitlement programs which only require simple mathematical models based upon large volumes of data and not complex modeling based on limited sampling.
7. If the government can't get a functional website up and running in 3+ years, why do you believe it has the expertise to respond to the challenge of man-made climate change?
Looking only at #3, there is no 17 year pause in most data sets. I imagine if you cherry pick temperature data you can find almost any pattern you want, but those agencies which use the largest data sets of global temperatures show remarkably consistent findings as shown in the video (and lots of other places). As far as "disrupting modern civilization", what do you think global warming will do to that? As I posted much earlier in this thread, it is imperative to get a better idea of why global warming is occuring, and if you can come up with a better way to do that than through government funded research I'd love to hear it. You can be sure there is no industry group (any industry) which has any interest in doing so.
As someone with a degree in Atmospheric Science, and work experience at NCAR and NWS, I always shake my head in disbelief at how people can allow a scientific debate such as this to be turned into a political one. Seriously, you're all being played! The reason why 'they' turn it into a political issue though is obvious, to divide us ... and in doing so truth no longer matters.
While I don't work actively in the field anymore, I do still have many connections who do. And the truth is there NO statistically relevant warming without the IPCC temperature adjustment figured into the equation. If you don't know exactly what I'm referring to (Google'ing to find out doesn't count), then you have no business forming an opinion either way. The entire argument for warming is based on those adjustments, not climate models. The models are crap, everybody in the field knows they're crap, and 20 years of failure has proven they're crap. If you insist on having an opinion you must first understand the temperature adjustments that have been applied to data from past years, and then you'll see how the entire argument falls apart without them.
And more truth is cooling is a MUCH bigger danger than warming. The vast majority of the World's food supplies come from middle-latitudes, any cooling to disrupt that and we could very quickly face a true crisis!
While I don't work actively in the field anymore, I do still have many connections who do. And the truth is there NO statistically relevant warming without the IPCC temperature adjustment figured into the equation. If you don't know exactly what I'm referring to (Google'ing to find out doesn't count), then you have no business forming an opinion either way. The entire argument for warming is based on those adjustments, not climate models. The models are crap, everybody in the field knows they're crap, and 20 years of failure has proven they're crap. If you insist on having an opinion you must first understand the temperature adjustments that have been applied to data from past years, and then you'll see how the entire argument falls apart without them.
And more truth is cooling is a MUCH bigger danger than warming. The vast majority of the World's food supplies come from middle-latitudes, any cooling to disrupt that and we could very quickly face a true crisis!
Well, since we can't Google to learn, but we need to know what it is in order to have an opinion, then you have to tell us.
That's exactly my point. Being such a fundamental part of the entire argument, unless you understand intimately what I'm talking about, you shouldn't have an opinion ... it's a scientific debate. Those who do form opinions without the requisite understanding only do so out of partisan political motivations.
I agree. Our time would be much better spent figuring out how to clean up all the crap we have spread around the planet. Maybe we should concentrate on how to stop defoliating rain forests, rather than worrying about climate change, which was what, a hundredth of a degree for the entire last one hundred years? It isn't that we shouldn't take care of our environment because there is plenty of work to be done, but we shouldn't buy into patent bullshit, either.
Localized environmental effects from human activity are undeniable. And yes we should strive to be better stewards of the planet which gives us all life. That doesn't however involve carbon credits. Hell, the amount of money doled out for bogus research could have paid 100x over to extinguish all the Mongolian coal mine fires, and instantly decreased global CO2 output by 3-4%. Not to mention all the regional environmental benefits, and preserving the cleanest burning coal in the World.
The problem is that it appears to be a political debate. Even in "lay" science periodicals like Scientific American and Science News there is no suggestion of any real disagreement among climate and atmospheric scientists.
Exactly, and as usual, it is the conspiracy theorists who try to make it political. Makes me think there is a conspiracy to make climate change a conspiracy.
If you're talking about degrees Celsius, it's been about 1/3 of a degree in the last 30 years, according to vapor's IPCC.
Global Warming and Climate Change Facts
What does past climate change tell us about global warming?
Science says: Climate reacts to whatever forces it to change; humans are now the dominant force.
A common skeptic argument is that climate has changed naturally in the past, long before SUVs and coal-fired power plants, so therefore humans cannot be causing global warming now. Interestingly, the peer-reviewed research into past climate change comes to the opposite conclusion. To understand this, first you have to ask why climate has changed in the past. It doesn't happen by magic. Climate changes when it's forced to change. When our planet suffers an energy imbalance and gains or loses heat, global temperature changes.
There are a number of different forces which can influence the Earth's climate. When the sun gets brighter, the planet receives more energy and warms. When volcanoes erupt, they emit particles into the atmosphere which reflect sunlight, and the planet cools. When there are more greenhouse gases in the atmosphere, the planet warms. These effects are referred to as external forcings because by changing the planet's energy balance, they force climate to change.
It is obviously true that past climate change was caused by natural forcings. However, to argue that this means we can't cause climate change is like arguing that humans can't start bushfires because in the past they've happened naturally. Greenhouse gas increases have caused climate change many times in Earth's history, and we are now adding greenhouse gases to the atmosphere at a increasingly rapid rate.
Looking at the past gives us insight into how our climate responds to external forcings. Using ice cores, for instance, we can work out the degree of past temperature change, the level of solar activity, and the amount of greenhouse gases and volcanic dust in the atmosphere. From this, we can determine how temperature has changed due to past energy imbalances. What we have found, looking at many different periods and timescales in Earth's history, is that when the Earth gains heat, positive feedbacks amplify the warming. This is why we've experienced such dramatic changes in temperature in the past. Our climate is highly sensitive to changes in heat. We can even quantify this: when you include positive feedbacks, a doubling of CO2 causes a warming of around 3°C.
What does that mean for today? Rising greenhouse gas levels are an external forcing, which has caused climate changes many times in Earth's history. They're causing an energy imbalance and the planet is building up heat. From Earth's history, we know that positive feedbacks will amplify the greenhouse warming. So past climate change doesn't tell us that humans can't influence climate; on the contrary, it tells us that climate is highly sensitive to the greenhouse warming we're now causing.
Is the Sun causing global warming?
Science says: In the last 35 years of global warming, sun and climate have been going in opposite directions.
Global temperature (red, NASA GISS) and total solar irradiance (blue, 1880 to 1978 from Solanki, 1979 to 2009 from PMOD).
Over the last 30 years of global warming, the sun has shown a slight cooling trend. Sun and climate are going in opposite directions. This has led a number of scientists independently concluding that the sun cannot be the cause of recent global warming.
One of the most common and persistent climate myths is that the sun is the cause. This argument is made by cherry picking the data - showing past periods when sun and climate move together but ignoring the last few decades when the two diverge.
Does global warming have an upside?
Science says: Negative impacts of global warming on agriculture, health, and environment far outweigh any positives.
Agriculture
While CO2 is essential for plant growth, all agriculture depends also on steady water supplies, and climate change is likely to disrupt those supplies through floods and droughts. It has been suggested that higher latitudes—Siberia, for example—may become productive due to global warming, but the soil in Arctic and bordering territories is very poor, and the amount of sunlight reaching the ground in summer will not change because it is governed by the tilt of the earth. Agriculture can also be disrupted by wildfires and changes in seasonal periodicity, which is already taking place, and changes to grasslands and water supplies could impact grazing and welfare of domestic livestock. Increased warming may also have a greater effect on countries whose climate is already near or at a temperature limit over which yields reduce or crops fail—in the tropics or sub-Sahara, for example.
Health
Warmer winters would mean fewer deaths, particularly among vulnerable groups like the aged. However, the same groups are also vulnerable to additional heat, and deaths attributable to heat waves are expected to be approximately five times as great as winter deaths prevented. It is widely believed that warmer climes will encourage migration of disease-bearing insects like mosquitoes and malaria is already appearing in places it hasn't been seen before.
Polar Melting
While the opening of a year-round ice free Arctic passage between the Atlantic and Pacific oceans would confer some commercial benefits, these are considerably outweighed by the negatives. Detrimental effects include loss of polar bear habitat and increased mobile ice hazards to shipping. The loss of ice albedo (the reflection of heat), causing the ocean to absorb more heat, is also a positive feedback; the warming waters increase glacier and Greenland ice cap melt, as well as raising the temperature of Arctic tundra, which then releases methane, a very potent greenhouse gas (methane is also released from the sea-bed, where it is trapped in ice-crystals called clathrates). Melting of the Antarctic ice shelves is predicted to add further to sea-level rise with no benefits accruing.
Ocean Acidification
A cause for considerable concern, there appear to be no benefits to the change in pH of the oceans. This process is caused by additional CO2 being absorbed in the water, and may have severe destabilizing effects on the entire oceanic food-chain.
Melting Glaciers
The effects of glaciers melting are largely detrimental, the principle impact being that many millions of people (one-sixth of the world's population) depend on fresh water supplied each year by natural spring melt and regrowth cycles and those water supplies—drinking water, agriculture—may fail.
Sea Level Rise
Many parts of the world are low-lying and will be severely affected by modest sea rises. Rice paddies are being inundated with salt water, which destroys the crops. Seawater is contaminating rivers as it mixes with fresh water further upstream, and aquifers are becoming polluted. Given that the IPCC did not include melt-water from the Greenland and Antarctic ice-caps due to uncertainties at that time, estimates of sea-level rise are feared to considerably underestimate the scale of the problem. There are no proposed benefits to sea-level rise.
Environmental
Positive effects of climate change may include greener rain forests and enhanced plant growth in the Amazon, increased vegetation in northern latitudes and possible increases in plankton biomass in some parts of the ocean. Negative responses may include further growth of oxygen poor ocean zones, contamination or exhaustion of fresh water, increased incidence of natural fires, extensive vegetation die-off due to droughts, increased risk of coral extinction, decline in global photo-plankton, changes in migration patterns of birds and animals, changes in seasonal periodicity, disruption to food chains and species loss.
Economic
The economic impacts of climate change may be catastrophic, while there have been very few benefits projected at all. The Stern report made clear the overall pattern of economic distress, and while the specific numbers may be contested, the costs of climate change were far in excess of the costs of preventing it. Certain scenarios projected in the IPCC AR4 report would witness massive migration as low-lying countries were flooded. Disruptions to global trade, transport, energy supplies and labour markets, banking and finance, investment and insurance, would all wreak havoc on the stability of both developed and developing nations. Markets would endure increased volatility and institutional investors such as pension funds and insurance companies would experience considerable difficulty.
Developing countries, some of which are already embroiled in military conflict, may be drawn into larger and more protracted disputes over water, energy supplies or food, all of which may disrupt economic growth at a time when developing countries are beset by more egregious manifestations of climate change. It is widely accepted that the detrimental effects of climate change will be visited largely on the countries least equipped to adapt, socially or economically.
Do scientists agree about global warming?
Science says: 97% of climate experts agree humans are causing global warming.
Science achieves a consensus when scientists stop debating. When a question is first asked—like "what would happen if we put a load more CO2 in the atmosphere?"—there may be many hypotheses about cause and effect. Over a period of time, each idea is tested and retested (the scientific method) because reputation and kudos go to those who find the right answer. Nearly all hypotheses will fall by the wayside during this testing period, because only one is going to answer the question properly, without leaving all kinds of odd dangling bits that don't quite add up. Bad theories are usually rather untidy.
Eventually, the testing period must come to an end. The focus of investigation narrows down to those avenues that continue to make sense, that still add up, and quite often a good theory will reveal additional answers, or make powerful predictions that add substance to the theory. When Russian scientist Dmitri Mendeleev constructed the periodic table of elements, not only did he fit all known elements successfully, he predicted that elements we didn't even know about would turn up later on, and they did!
So a consensus in science is different from a political one. There is no vote. Scientists give up the debate because the sheer weight of consistent evidence is too compelling, the tide too strong to swim against any longer. Scientists change their minds on the basis of the evidence, and a consensus emerges over time. Not only do scientists stop debating, they also start relying on each others' work. All science depends on that which precedes it, and when one scientist builds on the work of another, he acknowledges the work of others through citations. The work that forms the foundation of climate change science is cited with great frequency by many other scientists, demonstrating that the theory is widely accepted and relied upon.
In the field of climate studies, which is informed by many different disciplines, the consensus is demonstrated by the number of scientists who have stopped debating what is causing climate change—and that's nearly all of them. A survey of all peer-reviewed papers on the subject "global climate change" published between 1993 and 2003 shows that not a single paper rejected the consensus position that global warming is man-made. 75% of the papers agreed with the consensus position while 25% made no comment either way, focusing on methods analysis instead (Oreskes 2004).
Several subsequent studies confirm that "...the debate on the authenticity of global warming and the role played by human activity is largely nonexistent among those who understand the nuances and scientific basis of long-term climate processes." (Doran 2009). In other words, more than 95% of scientists working in the disciplines contributing to studies of our climate, accept that climate change is almost certainly being caused by human activities.
We should also consider official scientific institutions and what they think about climate change. There are no national or major scientific institutions anywhere in the world that dispute the theory of anthropogenic climate change. Not one.
In the field of climate science, the consensus is unequivocal: human activities are causing climate change.
Is global warming still happening?
Science says: All the indicators show that global warming is still happening.
Seven of these indicators would be expected to increase in a warming world and observations show that they are increasing. Three would be expected to decrease and they are decreasing.
When looking for evidence of global warming, there are many different indicators that we should look for. While it's natural to start with air temperature, a more thorough examination should be as inclusive as possible: snow cover, ice melt, air temperature over land and sea, even the sea temperature itself. A 2010 study included 10 key indicators, and as shown above, every one of them is moving in the direction expected of a warming globe.
The question of global warming stopping is often raised in the when weather events that we don't typically associate with global warming happen—a big winter storm or drought-relieving rain. Global warming is entirely compatible with these events; after all, they are just weather. In climate change, it is the long-term trends that are important; measured over decades or more, and the long term trends show that the globe is still warming.
How reliable are climate models?
Science says: Models successfully reproduce global temperature since 1900.
Climate models are mathematical representations of the interactions between the atmosphere, oceans, land surface, ice, and the sun. This is clearly a very complex task, so models are built to estimate trends rather than events. For example, a climate model can tell you it will be cold in winter, but it can't tell you what the temperature will be on a specific day—that's weather forecasting. Climate is weather averaged out over time, usually 30 years. Trends are important because they smooth out single events that may be extreme, but quite rare.
Climate models have to be tested to find out if they work. We can't wait for 30 years to see if a model is any good or not; models are tested against the past, against what we know happened. If a model can correctly predict trends from a starting point somewhere in the past, we could expect it to predict with reasonable certainty what might happen in the future.
So all models are first tested in a process called "hindcasting." The models used to predict future global warming can accurately map past climate changes. If they get the past right, there is no reason to think their predictions would be wrong. Testing models against the existing instrumental record suggested CO2 must cause global warming, because the models could not simulate what had already happened unless the extra CO2 was added to the model. All other known forcings are adequate in explaining temperature variations prior to the rise in temperature over the last thirty years, while none of them are capable of explaining the rise in the past thirty years. CO2 does explain that rise, and explains it completely without any need for additional, as yet unknown forcings.
Where models have been running for sufficient time, they have also been proved to make accurate predictions. For example, the eruption of Mt. Pinatubo allowed modelers to test the accuracy of models by feeding in the data about the eruption. The models successfully predicted the climatic response after the eruption. Models also correctly predicted other effects subsequently confirmed by observation, including greater warming in the Arctic and over land, greater warming at night, and stratospheric cooling.
The climate models, far from being alarmist, may be conservative in the predictions they produce. For example, here's a graph of sea level rise:
Sea level change; tide gauge data are indicated in red and satellite data in blue. The grey band shows the projections of the IPCC Third Assessment report (Copenhagen Diagnosis 2009).
Here, the models have understated the problem. In reality the events are all within the upper range of the model's predictions. There are other examples of models being too conservative, rather than alarmist as some portray them. All models have limits (uncertainties) for they are modeling chaotic systems. However, all models improve over time, and with increasing sources of real-world information such as satellites, the output of climate models can be constantly refined to increase their power and usefulness.
Climate models have already predicted many of the phenomena for which we now have empirical evidence. Climate models form a reliable guide to potential climate change.
Are surface temperature records reliable?
Science says: The warming trend is the same in rural and urban areas, measured by thermometers and satellites.
Surveys of weather stations in the USA have indicated that some of them are not sited as well as they could be. This calls into question the quality of their readings.
However, when processing their data, the organizations which collect the readings take into account any local heating or cooling effects, such as might be caused by a weather station being located near buildings or near tarmacs at an airport. This is done, for instance, by weighting (adjusting) readings after comparing them against those from more rural weather stations nearby.
More importantly, for the purpose of establishing a temperature trend, the relative level of single readings is less important than whether the pattern of all readings from all stations taken together is increasing, decreasing, or staying the same from year to year. Furthermore, since this question was first raised, research has established that any error that can be attributed to poor siting of weather stations is not enough to produce a significant variation in the overall warming trend being observed. Even groups that have recreated the global temperature record on their own, with the intent to prove that there are problems with the data, have admitted that there is no substance to the claim.
It's also vital to realize that climate change not based simply on ground level temperature records. Other, completely independent temperature data compiled from weather balloons, satellite measurements, and from sea and ocean temperature records, also tell a remarkably similar warming story.
Confidence in climate science depends on the correlation of many sets of these data from many different sources in order to produce conclusive evidence of a global trend.
Can animals and plants adapt to global warming?
Science says: Global change is happening too fast for the ecosystem to adapt.
Humans are transforming the global environment. Great swathes of temperate forest in Europe, Asia, and North America have been cleared over the past few centuries for agriculture, timber, and urban development. Tropical forests are now on the front line. Human-assisted species invasions of pests, competitors, and predators are rising exponentially, and over-exploitation of fisheries and forest animals for bush meat continues to be the rule rather than the exception.
Given these existing pressures and upheavals, it is a reasonable question to ask whether global warming will make any further meaningful contribution to this mess. Some see no danger at all, maintaining that a warmer planet will be beneficial for mankind and other species on the planet, and that "corals, trees, birds, mammals, and butterflies are adapting well to the routine reality of changing climate."
However, global warming has already affected the ecosystem by changing where some species can survive, the timing of breeding, migration, flowering, and so on. Although it's difficult to predict the future extinction risk, some scientists have found that 18 to 35% of plant and animal species will be committed to extinction by 2050 due to climate change.
A large number of ancient mass extinction events have indeed been strongly linked to global climate change, including the most sweeping die-off that ended the Palaeozoic Era, 250 million years ago, and the less cataclysmic Palaeocene-Eocene Thermal Maximum, 55 million years ago. These extinctions were natural, and there are a number of reasons why today's global change will have a particularly severe impact on biodiversity:
•Post-industrial man-made warming is already more rapid than anything the Earth has seen before, and it is expected to accelerate.
•An optimistic projection of future temperature is 2°C, which will shift the Earth's mean temperature into conditions which haven't existed since 3 million years ago. A more realistic projection, 4°C, will shift the Earth's climate back to the largely ice-free world that existed prior to 35 million years ago. When considering that the average species' "lifetime" is 1-3 million years, it easy to understand that our new climate will be unlike anything today's species have ever seen.
•Today's ecosystems have already been impacted by climate change. Most habitats are already degraded and their populations depleted by past human activities. For millennia our impacts have been localized although often severe, but during the last few centuries we have unleashed physical and biological transformations on a global scale. Feedbacks from global warming, ocean acidification, habitat loss, habitat fragmentation, invasive species, and chemical pollution will likely lead to cascading extinctions.
•Past adaptation to climate change by species was mainly through shifting their geographic range to higher or lower latitudes (depending on whether the climate was warming or cooling), or up and down mountain slopes. There were also evolutionary responses—individuals that were most tolerant to new conditions survived and so made future generations more intrinsically resilient. However, because of how fast the Earth is warming, and because of all the infrastructure humans have built (roads, railways, massive cities), time is up and there is nowhere for species to run or hide.
Hasn't the climate been cooling since 1998?
Science says: 2010 is globally the hottest year on record, tied with 2005.
No, it hasn't been cooling since 1998. Even if we ignore long term trends and just look at the record-breakers, that wasn't the hottest year ever. Different reports show that, overall, 2005 was hotter than 1998. What's more, globally, the hottest 12-month period ever recorded was from June 2009 to May 2010.
Is Antarctica gaining ice?
Science says: Satellites measure Antarctica is gaining sea ice but losing land ice at an accelerating rate, which has implications for sea level rise.
Skeptic arguments that Antarctica is gaining ice frequently hinge on an error of omission, namely ignoring the difference between land ice and sea ice.
In glaciology, and particularly with respect to Antarctic ice, not all things are created equal. Let us consider the following differences. Antarctic land ice is the ice which has accumulated over thousands of years on the Antarctica landmass itself through snowfall. This land ice therefore is actually stored ocean water that once fell as precipitation. Sea ice in Antarctica is quite different as it is generally considered to be ice which forms in salt water primarily during the winter months.
Estimates of Total Antarctic Land Ice Changes and approximate sea level contributions using many different measurement techniques. Adapted from The Copenhagen Diagnosis. (CH= Chen et al. 2006, WH= Wingham et al. 2006, R= Rignot et al. 2008b, CZ= Cazenave et al. 2009 and V=Velicogna 2009)
In Antarctica, sea ice grows quite extensively during winter but nearly completely melts away during the summer (see above). That is where the important difference between antarctic and arctic sea ice exists. Arctic sea ice lasts all the year round, there are increases during the winter months and decreases during the summer months but an ice cover does in fact remain in the North which includes quite a bit of ice from previous years (Figure 1). Essentially Arctic sea ice is more important for the earth's energy balance because when it melts, more sunlight is absorbed by the oceans whereas Antarctic sea ice normally melts each summer leaving the earth's energy balance largely unchanged.
One must also be careful how you interpret trends in Antarctic sea ice. Currently this ice is increasing and has been for years but is this the smoking gun against climate change? Not quite. Antarctic sea ice is gaining because of many different reasons but the most accepted recent explanations are listed below:
•Ozone levels over Antarctica have dropped causing stratospheric cooling and increasing winds which lead to more areas of open water that can be frozen (Gillet 2003, Thompson 2002, Turner 2009).
•The Southern Ocean is freshening because of increased rain, glacial run-off and snowfall. This changes the composition of the different layers in the ocean there causing less mixing between warm and cold layers and thus less melted sea ice (Zhang 2007).
All the sea ice talk aside, it is quite clear that really when it comes to Antarctic ice, sea ice is not the most important thing to measure. In Antarctica, the most important ice mass is the land ice sitting on the West Antarctic Ice Sheet and the East Antarctic Ice Sheet.
Estimates of recent changes in Antarctic land ice (see above) range from losing 100 gigatons/year to over 300 gigatons/year. Because 360 gigatons/year represents an annual sea level rise of 1 mm/year, recent estimates indicate a contribution of between 0.27 mm/year and 0.83 mm/year coming from Antarctica. There is of course uncertainty in the estimations methods but multiple different types of measurement techniques (explained here) all show the same thing, Antarctica is losing land ice as a whole, and these losses are accelerating quickly.
Global Warming and Climate Change Facts
http://www.wunderground.com/climate/facts.asp
The Scientific Consensus on Climate Change
http://www.wunderground.com/resources/climate/928.asp?MR=1
The political debate should be about what policy is best to address the fact of global warming.
Somehow it has become about the facts themselves.
I'd say those last 3 posts pretty well summarize the fallacy of the Global Warming argument.
One person cut-and-pastes and article that he doesn't understand, and probably didn't even read. If he did understand and read, he would have certainly recognized the numerous outright lies and distortions found within. Really, that 'story' is laughable for it's transparent pseudo-science. I'm assuming that came from Weather Underground? Knowing Jeff Masters personally I'm not surprised, that guy has been willing to do whatever it takes to 'sell' Global Warming since day one.
So one lay-person cut-and-pastes ridiculous story full of holes, then following 2 lay-people just swallow it whole, never once bothering to ask themselves questions about the veracity of data and information represented. I'm just waiting for another lay-person to regurgitate, "But 97% of scientists agree that it's fact!". Then the circle would be complete.
One person cut-and-pastes and article that he doesn't understand, and probably didn't even read. If he did understand and read, he would have certainly recognized the numerous outright lies and distortions found within. Really, that 'story' is laughable for it's transparent pseudo-science. I'm assuming that came from Weather Underground? Knowing Jeff Masters personally I'm not surprised, that guy has been willing to do whatever it takes to 'sell' Global Warming since day one.
So one lay-person cut-and-pastes ridiculous story full of holes, then following 2 lay-people just swallow it whole, never once bothering to ask themselves questions about the veracity of data and information represented. I'm just waiting for another lay-person to regurgitate, "But 97% of scientists agree that it's fact!". Then the circle would be complete.
Funny how the western mind is conditioned to be reducing all issues to yes/no, right/wrong and black/white (binary logic).
Here is how we should look at this. Based on the evidence, there is a probability that (A) global warming (within a specific time period) is taking place, and (B) the cause is man made. You can also translate that into accepting the null hypothesis (A) and (B) with certain confidence level. Anyone claiming that probability (A) and (B) are both zero has his head up his ass, and the same is true for anyone claiming that (A) and (B) are 100%.
Calculating (A) is strictly an exercise in statistics, and I suspect analysis of the temperature time series over the last few hunderd years, there is a close to 100% probability average temperature is raising. (B) cannot be calculated with absolute mathematical certainty, because there is no multi-variance regression model that explains 100% of variance of temperature.
Here is how we should look at this. Based on the evidence, there is a probability that (A) global warming (within a specific time period) is taking place, and (B) the cause is man made. You can also translate that into accepting the null hypothesis (A) and (B) with certain confidence level. Anyone claiming that probability (A) and (B) are both zero has his head up his ass, and the same is true for anyone claiming that (A) and (B) are 100%.
Calculating (A) is strictly an exercise in statistics, and I suspect analysis of the temperature time series over the last few hunderd years, there is a close to 100% probability average temperature is raising. (B) cannot be calculated with absolute mathematical certainty, because there is no multi-variance regression model that explains 100% of variance of temperature.
..so all you guys who keep your amps running 24/7 should think about cutting back on your KWH usage and save the big blue marble
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