is global warming human-induced?
444694
Read Michael Crichton's State of Fear. From my various reading I have learned that the earth was warmer in 1300 A.D. long before cars and it was one of the most prosperous times in history. This was before the Black Plague, of course. More land was arable and human and animal populations were flourishing. It is really impossible to tell as the Earth is in the middle of a natural warming period right now. The tree huggers will never tell you about the glaciers in Iceland that are getting bigger and the parts of Antarctica where the ice sheet is getting thicker. I am a liberal, I am for nurturing the environment. I believe common sense dictates that vehicle emissions are bad for the earth in making our air more noxious, but to answer your specific question, nobody knows because there are too many factors.
1121149
Many scientists believe that we are actually heading toward a global ice-age as opposed to a global warming.  \n\nAlthough a work of FICTION Michael Crichton's "State of Fear" provides evidence to support this.\n\nI suggest reading it (it's FIRST AND FOREMOST a good FICTION book, but is supported by genuine theories and statistics that ARE IN FACT from "Science" and "Nature" magazines, the worlds fore-most scientific mags)\n\nTo be honest I don't think we're experiencing anything unnatural about our environment right now.
806691
Global Warming is taking place, and I am not so sure it is just the people who are the culprits of this catastrophic event. There are much deeper reasons for this phenomenon that is taking place. We may be contributing to this problem. But  we alone aren't the only contributing factors. Scientists are studying this, and they have other theories. Reverse polarities may be taking place. \nPersonally, I think that because the Earth spins slightly off its axis, thus it has a wobble, and the Earth is coming to a stop. The sun is a powerful force, and as the Earth slows, sun's effects upon us are becoming more and more prolific. Cancer is more prevalent than ever before, for just one example. \nYes, Global Warming is happening, and I don't know if we are really able to stop it, or how much we contribute to the problem. We may be speeding up the process, but I don't think we are completely to blame.
1174608
I've answered this question about a million times now in some form or other....\n\nThe Earth is a complex and robust system that operates with a number of positive and negative feedback systems. This means that all the systems are interconnected and all the systems change through time.\n\nWhat a lot of people miss is that humans are part of the system too. By virtue of our very existence, we change the environment.\n\nThe media has confused a lot of people about the climate-change/global warming situation. The fact is, we do know what causes global warming. Greenhouse gases like CO2. We also know that industry produces a large quantity of these gases. In fact the levels of CO2 in our atmosphere have more than doubled since the industrial revolution.\n\nNow you can sit there and tell me that Earth changes the levels of CO2 in the atmosphere naturally, and you'd be right. But does it not seem like a huge coincidence that the increase in CO2 levels, and the onset of global warming are occurring together?\n\nThe Earth is warming naturally, but it doesn't take an Earth Scientist to work out that dumping huge volumes of greenhouse gas into the atmosphere is likely to make it worse. Pretending its nothing to do with humans doesn't mean we can afford to ignore that it's happening either!
262988
Neat how the graph excludes prior dates.  20 years ago it was global cooling.\n\nThe temperature varies, greenhouse gasses come from natural occurrences (Krakatoa and Mt. Saint Helens spewed more greenhouse gasses in the air than man has produced in 10,000 years).  The earth recovers.  Liberal activists don't.
435225
--Humans cut down forests and woodlands and plough the soil for agricultural purposes to produce more food. This decreases photosynthesis and there is less utilization of CO2 and so the atmospheric CO2 increases in concentration, hence disturbing the carbon cycle and leading to global warming.\n--Due to the increasing human population, more vehicles are now in use and the car exhaust release more of pollutant gases including CO2, and so the concentration of CO2 in air increases.\n--Excessive combustion of fossil fuels also release CO2 in the atmosphere and increase its concentration. This leads to global warming which has the following effects: (1) Melting of polar ice caps due to increased temperature, resulting in floods. (2) Evaporation of water from water bodies, altering the rainfall pattern and climatic conditions. (3) More evaporation of water from the soil, leading to drought and famine.\nHowever, and increase in temperature increases the rate of photosynthesis. Hence more of 02 is evolved and the cycle can be brought back to normal.
144171
Global warming is due to the huge quantity of some kind of gaz that human activity ejects in the atmospher. That gaz in itself does not warm, but it has indirect effects: destroying the earth's protection towards these sunshines and keeping the heat of these sunshines into the earth's atmospher.\nWhy people don't care much about it? It's because they don't realize that the earth as they know it could drastically change. Until now, it took billions of years to change, so human lifetime (and even the complete human History!!!) isn't much compared to the usual scale of big climate changes. But the earth human population, its activity and its ability to pollute have increased so much that it has become possible for humanity to go straight into a wall without even realizing it!!!
809748
Back in the 70s it was global cooling.  How quickly things change.  Climates get hotter and cold in cycles.  And according to scientists, we've been experiencing global warming since the last ice age.  Doesn't secular history say that the world has already gone through a warming an dcooling cycle several times?  Global warming may be slightly accelerated by industrial activity, but the truth is that our climate is alot bigger than us.  It will get wrmer or cooler with or without our help.
118898
Did you mean Global Warming?\nGlobal warming is an increase in the average temperature of the Earth's atmosphere and oceans. The term is also used for the scientific theory of anthropogenic global warming, which attributes much of the recently observed and projected global warming to a human-induced intensification of the greenhouse effect.\n\nFor more info go to http://en.wikipedia.org/wiki/Global_Warming
283596
This is such a confused issue. \n\nThe short answer is: maybe, but we really do not know. \n\nThe greenhouse gases that are in the earth's atmosphere now keep its temperature warmer by about 60 degrees F. These gases include water vapor (the most important), carbon dioxide, methane, and a few others.\n\nHow might humans increase the net number of greenhouse gases?\n- - - - - - - - - - - - - - - - - - - - - - - - - - - - \n\n\nBurning fossil fuels like coal and natural gas and oil results in the introduction of carbon dioxide into the atmosphere. Burning wood also does so. Deforestation might reduce carbon dioxide sinks. Ocean pollution might also reduce carbon dioxide sinks by killing phytoplankton. Eutrophication (fertilizer in the water) creating algal blooms might also reduce carbon dioxide sinks (at least in the long run when they die and then rot, releasing more carbon dioxide). \n\nRaising cattle and growing rice can increase the greenhouse gas methane. CFCs and HCFCs are greenhouse gases produced by man. Ozone produced in our cities is also a greenhouse gas. Nitrous oxide produced by agriculture and industry is another greenhouse gas.\n\nDoes this have anything to do with global warming?\n - - - - - - - - - - - - - - - - - - - - - - - - - - - \n\nWe do not really know if the global warming we have observed in the last 100 years is natural, or due to human intervention. It might be some other process, like change in solar output. We really do not know, to be honest.  \n\nSo there are a lot of uncertainties. We just do not know, to be honest.
803494
Yes.  Global Warming is occuring.  It will just keep getting worse if we don't take measures to try and prevent things from getting worse.
1156242
Yes, Global warming is a reality.  Anyone who says otherwise is ignorant.   Yes, the earth goes throgh natural warming and cooling phases, we are currently trasistioning into a "hothouse" from an "icehouse" which means we are in an inter-glacial period.\n\nHowever, Humans are doing their part to screw up the atmosphere.  CO2 is a gas that traps heat  and is emmitted by cars, factories, and anything else that burns fuel to work.  All anyone needs to do is look at a graph of the average surface temperture for the earth superimposed on the CO2 level and they will find they are identical in shape.  And the CO2 level has increased exponentially since the industrial evolution.  While the earth's natural cycles have varied the CO2 levels from 150 to 280 parts per million in the last 600,000 years, we are currently at 390 parts per million and rising fast.  No that is not natural, it is caused by humans.\n\nWhat can you do?  Buy a Prius.  Recycle.  Use less - ride you bike more.  Run your AC less, Turn off your lights.  All those hippie things that save energy - they actually work.
1162504
Global warming is a term used to refer to the observed increase in the average temperature of the Earth's atmosphere and oceans in recent decades.\n\nThe Earth's average near-surface atmospheric temperature rose 0.6 ± 0.2 degrees Celsius (1.1 ± 0.4  degrees Fahrenheit) in the 20th century. The prevailing scientific opinion on climate change is that "most of the warming observed over the last 50 years is attributable to human activities" [1]. The increased amounts of carbon dioxide (CO2) and other greenhouse gases (GHGs) are the primary causes of the human-induced component of warming. They are released by the burning of fossil fuels, land clearing and agriculture, etc.\n\nThe measure of the climate response to increased GHGs, climate sensitivity, is found by observational studies and climate models. Doubling of CO2 in the atmosphere warms in the range 1.5-4.5  degrees C (2.7-8.1  degrees F). Models referenced by the Intergovernmental Panel on Climate Change (IPCC) predict that global temperatures may increase by between 1.4 and 5.8  degrees C (2.5 to 10.5  degrees F) between 1990 and 2100. The uncertainty in this range results from both the difficulty of predicting the volume of future greenhouse gas emissions and uncertainty about climate sensitivity.\n\nAn increase in global temperatures can in turn cause other changes, including a rising sea level and changes in the amount and pattern of precipitation. These changes may increase the frequency and intensity of extreme weather events, such as floods, droughts, heat waves, hurricanes, and tornados. Other consequences include higher or lower agricultural yields, glacier retreat, reduced summer streamflows, species extinctions and increases in the ranges of disease vectors. Warming is expected to affect the number and magnitude of these events; however, it is difficult to connect particular events to global warming. Although most studies focus on the period up to 2100, warming (and sea level rise due to thermal expansion) is expected to continue past then, since CO2 has a long average atmospheric lifetime. [2].\n\nOnly a small minority of scientists contest the view that humanity's actions have played a significant role in increasing recent temperatures. However, the uncertainty is more significant regarding how much climate change should be expected in the future, and there is a hotly contested political and public debate over what, if anything, should be done to reduce or reverse future warming, and how to cope with the consequences.\n\nThe term 'global warming' is a specific case of the more general term 'climate change' (which can also refer to cooling, such as occurs during ice ages). In principle, 'global warming' is neutral as to the causes, but in common usage, 'global warming' generally implies a human influence. However, the UNFCCC uses 'climate change' for human-caused change, and 'climate variability' for other changes [3]. Some organizations use the term 'anthropogenic climate change' for human-induced changes. Geological activity will not be affected except as above.
1107357
Global warming caused by humans is a myth.  It has been debunked by scientist after scientist.  The reason the earth is in a "warming cycle" (the temp on earth has risen 1 degree in the last 100 years..1 DEGREE) is because the sun is hotter.  \n\nThe environment is the new "religion" of the left, both in America and abroad. They don't believe in God and hate America.
17237
Global temperature has gone through many changes, some of which were natural cycles grounded in astronomy (solar activities, changes in earth's orbit), others of which have been natural catastrophes like meteoric strikes or huge volcanic eruptions. \n\nThe rapid consumption of fossile fuels and the production of other greenhouse gases doubtlessly has influenced the average temperature and increased the rise of it. Whether it is the sole determining factor cannot be said, because all observations can only be made overlaid with all the natural factors.\n\nFor this reason, experts still debate...
282103
Is the book you read "State of Fear"?\n\nYou can debate this all you want, but you wont get anywhere until you define 'global warming.'  I think I wrote a long-winded explanation in another answer, so search for that.\n\nThe long and the short of it is:\n\n1.  The Earth goes through natural warming and cooling, based on a HUGE range of varying natural processes, from changes in orbital paramaters to changes in sea ice thickness in polar regions.  It has done this since there were oceans and an atmosphere, and will always continue.\n\n2.  Humans have influenced certain properties of the atmosphere and hydrosphere that may be contributing to accelerated warming (ozone depletion, increased levels of 'greenhouse' gases, etc).  Since we dont know if the Earth would be warming anyway, we cant definitively say that a current warming trend is related to human influence (but its a good bet).\n\n3.  Global warming trends are difficult to understand.  As a paleoclimatologist, I dont even understand it.  I dont know where the temperature data has been collected, the spatial distribution of the data points, I dont know what the temperatures are being compared to (the Earth has been much warmer at times in the past), I dont know if the scientists who tabulate the data are being influenced by something other than true science, etc.\n\nBottom line is that its a VERY VERY complex problem.  Unfortunately, the more data that are generated, the more complex and vague the answer will become, and the more people will become divided over the interpretation of the data.\n\nIt would be wise to minimize our impact on the climate system (or any Earth system for that matter) as best we can, no matter what the answer is.  The more interesting question is: when will the next 'ice age' begin, if it hasnt already?!?!?
59118
Global warming is an increase in the average temperature of the Earth's atmosphere and oceans. The term is also used for the scientific theory of anthropogenic global warming, which attributes much of the recently observed and projected global warming to a human-induced intensification of the greenhouse effect. On this theory, the increased volumes of carbon dioxide and other greenhouse gases released mainly by the burning of fossil fuels, and, to a lesser extent, land clearing and agriculture, are the primary sources of warming. The natural greenhouse effect keeps the Earth 30 °C warmer than it otherwise would be; adding carbon dioxide to an atmosphere, with no other changes, will make a planet's surface warmer. Current research is attempting to find out more details about the processes and factors that would affect a temperature increase especially about positive and negative feedback mechanisms, to allow a more precise quantification of the effects of global warming.\n\nTemperature change is just one aspect of the broader subject of (human-induced) climate change. The scientific opinion on climate change, as expressed by the UN Intergovernmental Panel on Climate Change (IPCC) and explicitly endorsed by the national science academies of the G8 nations, is that the average global temperature has risen 0.6 ± 0.2 °C since the late 19th century, and that it is likely that "most of the warming observed over the last 50 years is attributable to human activities" [1]. A small minority of qualified scientists contest the view that humanity's actions have played a significant role in increasing recent temperatures. Uncertainties do exist regarding how much climate change should be expected in the future, and a hotly contested political and public debate exists over what actions, if any, should be taken in light of global warming.\n\nBased on basic science, observational sensitivity studies, and the climate models referenced by the IPCC, temperatures may increase by 1.4 to 5.8 °C between 1990 and 2100 [2]. This is expected to result in other climate changes including rises in sea level and changes in the amount and pattern of precipitation. Such changes may increase the frequency of extreme weather events such as floods, droughts, heat waves, and hurricanes, change agricultural yields, or contribute to biological extinctions. Although warming is expected to affect the number and magnitude of these events, it is very difficult to connect any particular event to global warming.