What evidence is there that global warming is entirely due to the activities of humans?

Answer 1

Personally I do not like the term Global Warming. I think Climate Change fits the bill much better. There is very little doubt that the usage of fossil fuels by us Humans is relesing large quantities of CO2 into our atmosphere which can cause the planet to heat up. However, what I fear people fail to realise is that in the Geologic past there have been times when the Earth has been hotter than it is now and we know that the Earth heats up and cools in cycles. The question really is how quickly are we accelerating Climate change?

Answer 2

NONE!! There is only evidence to the contrary.
In the last 100 years the sun's output increased by 2w/m2 this represents 1.4 times the maximum possible effect from CO2.
Clouds and water vapour represent 97% of the greenhouse gases by volume and 90% of the greenhouse effect and change in a way that is sufficient to explain all the current warming.
The human activity that has the greatest effect on the climate is the expanding urban heat islands and land use changes that affect the reflectivity of the Earth.
Solar variance and changes in cloud cover represent at least 75% of the 0.6 degrees C of warming, and even allowing for the most unrealistic assumptions for the human effect the most that it could be is the other 25% or 0.15 degrees of the current warming of the last 100 years.
The reason that this question was even asked is that science is being used to advance political adgendas.
The case in point is the Al Gore film an inconvenient truth which is being touted as a "scientific documentary". If it was scientific in nature it would have at least identified these other scientific facts as possible causes for global warming. Because it failed to do so, all of its premises are based on conjecture. The skill with which this conjecture is portrayed as fact makes for a very compelling case for human caused global warming which the public readily accepts. The link www.junkscience.com/Greenhouse is a 13 page scientific rebuttal to this movie called "The real inconvenient truth"
Millions of people will be exposed to the Al Gore film, but only hundreds of people will be exposed to the basic science at this link. The important question that needs to be asked isn't "what evidence" but why is the public not aware of the overwhelming body of scientific evidence that makes this question irrelevant

Answer 3

Little to none. Only about 1% of CO2 is considered to be a result of human activities, with the rest mainly due to volcanic activity. People love to talk about how the Arctic glaciers are melting, without acknowledging that the ice in Antarctica (where about 90% of the world's glaciers are) is thickening, not to mention that there's no reliable way of measuring sea levels. And you can't trust those models people present that say the world is going to be X-degrees hotter in the next 10-15 years which will make everything hotter than Satan's a--hole because none of those models can reliably predict volcanic activity and solar activity, as well as having a piss-poor understanding of cloud physics and future activity.

Finally, don't forget about the Global Cooling scare just a few years ago (look it up in Wikipedia), which was every bit as alarmist and political as Global Warming/Climate Change is today.

Answer 4

There are 2 facts about global warming....

Fact 1: Over the last 100 years, the amount of CO2 in the atmosphere has increased. Before I give you the figures, ask yourself what *you* think the figures are. Ask yourself a) What %age of the atmosphere was CO2 100 years ago, and b) how much has it increased by over the last century? Got yourself an answer now? OK, here are the true figures. A century ago the amount of CO2 in the atmosphere was approximately 300 parts per million. That's about 0.03%. Over the last century it has increased by approximately 80 parts per million, so that's an increase of slightly less than 27%. To put that into some kind of perspective, imagine a straight road exactly 1KM long. CO2 100 years ago would amount to about 30cm of that 1KM and the increase would be about 8cm - about the width of your hand... in 1KM. Not much, is it?

Fact 2: Average global temperatures have risen in the last 100 years by approximately 0.6 degrees Celsius. But remember, that's the *average* increase. In some parts of the world it is higher - the arctic, for example, has risen by as much as 1.4C. However, to keep the average down to 0.6C in other parts of the world the temperatures have risen much less or have even fallen.

But, the important thing is that there is no conclusive evidence that fact 1 is causing fact 2. For example, between the mid 40s and the mid 70s CO2 levels continued to rise, but over that 30 year period average global temperatures fell. So, if increasing CO2 levels cause temps to rise, how did that happen?

Also, it's important to remember that the Earth is not a stable environment; its climate changes all the time without any help from mankind at all. 10 thousand years ago we were in the grip of the last ice age; most of Britain was covered in a sheet of ice over a mile thick. Have we had global warming since then? Oh yes! Was mankind anything to do with it? Er? No!!!

And don't be fooled by the fact that so many scientists believe it's happening. Trust me, there are plenty around that don't, they are just not as vocal as those that do. And remember, scientists are far from infallible; just ask Galileo! For those who don't know he was the guy who vocally supported Copernicus' idea that the Sun, not the Earth, was at the centre of the solar system. He was threatened with excommunication if he didn't change his views. Even when he did he was still placed under house arrest for heresy.

Anyone still believe that the Earth is at the centre of the solar system? No? Well then, don't be too quick to believe in global warming just yet. I suggest you join me on the fence. :)

Answer 5

The evidence as far as I am aware is that global warming is happening, and that a large part of this is due to human activity.

The temperature is changing, we can see this ourselves, we have witnessed several of the hottest summers ever in recent years, and milder winters.

There is also large scale scientific records of rising temperatures. There have been world records of temperature for approximately 150 years. These have been steadily rising since the early 20th century, but the rate at which they are rising has been much steeper in the last 15 years.

Experiments have shown that gases such as carbon dioxide and methane in the atmosphere trap sunlight energy. This can lead to warming.

The major cause of increasing carbon dioxide in the atmosphere is human burning of fossil fuels.

The concentration of carbon dioxide in the atmosphere has been measured for approximately 200 years, and concentrations in the far past have been found by analysing gas in thousands of year ols ice in the polar caps. Over 200 years, they have been rising with industrialisation, but over the last 20 years the rate at which they are rising has become much steeper.

The increased rates of temperature increase and carbon dioxide concentration increase have mirrored each other so accurately that this gives compelling evidence that the changing carbon dioxide concentration has played some part in changing the temperature.

So there is evidence that human activity is partly to blame, although I would dispute that there is compelling evidence that it is ENTIRELY to blame for climate change.

Answer 6

None. Much is based on the greenhouse gases ,and the major is CO2 ,which should be tremendous but they do not take all thing into there formula. Considering the billions of cf. of CO2 that is produced by combustion and even the breathing of 6,000,000,000 people. You try to measure CO2 and what do u get is 1 to 2 parts per million,which is nothing where did it go?? The beautiful green plants adsorbed it and produce OX.
How do u like that if CO2 isn't present there is no global warming

Answer 7

Arguments that the increase in carbon dioxide levels are natural and not due to human activities are absurd. It is very easy to measure how much fuel we use, and chemistry will tell us how much carbon dioxide that is putting into the air.

(Since I can't embed images, I have to link to them)
This graph shows global emissions of carbon dioxide since 1800.
http://img138.imageshack.us/my.php?image=globalcarbonemissionbytypema0.jpg
Notice how the emissions have increased dramatically since the start of the industrial revolution and continued increasing.

This graph shows total carbon dioxide levels over the past 400,000 years (notice current time is on the left, 400,000 years ago is to the right.)
http://img138.imageshack.us/my.php?image=carbondioxide400kyryu3.jpg
Notice we are currently far above any previous carbon dioxide levels.

Finally, temperature change since 1880 is graphed here:
http://img138.imageshack.us/my.php?image=0154aopenelementfieldelemformatgifvw3.jpg
There is a lot of variation to be sure, but the increasing temperature trend is clear.

So what does all this mean? Our friends in the chemistry department can tell you that carbon dioxide, along with other "greenhouse gases" trap infrared radiation near the surface of the earth leading to increasing temperatures. So, if you are smart enough to put 2 and 2 together, you will know that human activities are increasing global temperature. The only area that is fishy is how much we are increasing the temperature, and the truth is that any scientist claiming to have a definite answer is full of "it." The best and most current scientific models show temperature increases between 1.5 and 6 degrees Celsius over the next 100 years
http://img212.imageshack.us/my.php?image=esu501p5modelsang9.jpg
That is quite a lot of variation considering the stability of the past 100 years.

In answer to some previous "proofs" that humans are not affecting global climate change.

"Water vapor is the number 1 greenhouse gas"
Yes it is, but humans have absolutely no control over it. What we do know is that we are causing an increase in carbon dioxide levels, that this will increase temperature, and that increased temperatures lead to more evaporation of water. Measuring the "direct" effect of carbon dioxide on temperature is not enough because it's effects will be multiplied many times over by it's indirect effects.

"Ice in the Antarctic is thickening"
Possibly the dumbest proof I have ever heard. Think about it, if temperature increases from -15 degrees Celsius to -12 degrees Celsius, is the ice going to start melting? Of course not, because ice doesn't melt until 0 degrees Celsius. (Mean annual temperature of Antarctica is -57 degrees C.) As long as it occasionally snows, the ice is going to get thicker.

And I skimmed through www.junkscience.com/Greenhouse , it does not even take a side in the argument of human impacts on global warming. Overall, it seems a fair, fact-based article on what the terms "global warming" and "greenhouse effect" mean.

Answer 8

i think the actual tale is taking position immediately. seem at each and every of the unusual climate ameliorations purely this twelve months on my own. I do believe there are international ameliorations immediately. extremely warm temps. in places that do not adventure those warm temps. for such lengthy classes time. social gathering: the position I stay, north woods, Wisconsin, no human being ever needed AC because the temps were continually at a actual looking temp. were given some ninety degree days, yet except that that is continually been cooler the added north you go. particular has replaced considering we first began coming as a lot because the north woods. hotter, yet gentle temps, yet getting hotter and warmth summers and hotter winters. There are extra trees contained in the north woods which make for extra gentle temps contained in the summer. Can tell the version if we visit city (attack) it is about 12-14 miles aways. Temps will climb with the aid of 5-8 ranges massive difference. the a lot less trees you've the hotter the temps will be. we've also been in drought circumstances for the previous 6 years. extra rain this twelve months, yet nevertheless favor plenty extra to ensure that the lakes again to familiar ranges. Lake of snow will also make a huge difference concerning temps and moisture. This summer has been a warm one like maximum different places with loopy dew factors. States that favor rain, are not getting any, at the same time as states who're getting rain have become too a lot rain. record snow falls, record rain falls. certain I do believe the completed cycle is replacing and could proceed to regulate. i have study that years in the past already about climate ameliorations. Our iciness's are already replacing proper alongside with our summers. i think we are all going to be in for a tremendous variety of climate ameliorations and that incorporates extra negative storms. platforms are butting up adversarial to at least one yet another further and extra with the elements ameliorations that all of us is experiencing. hence extra negative storms, extra unusual snow falls and the record is going on. call it what you want, yet our climate is unquestionably replacing and could proceed to attain this. shop scaling down the trees and that is going to in hardship-free words come swifter.

Answer 9

To some extent it is circumstantial. We do know what the effect of CO2 and methane in the atmosphere is and fully understand the way in which it traps radiation of certain wavelengths in the infra-red. This is clearly going to have an effect on both surface temperature and air temperature. If the sea temperature increases it can dissolve less CO2 and more is released increasing the effect of warming.
Similarly warming will obviously melt ice and this will have an effect on the sea level and on the amount of radiation reflected back into space.
The key is CO2 and the amount in the atmosphere has increased in direct proportion to the amount of fossil fuels burned.
I see that you have the inevitable mad Yank in denial.

Answer 10

There is no need of evidence. We can just keep our eyes shut and say that we are not the cause of the global warming.

Or we can just listen and feel the things around us that are changing and screaming at us telling us to stop destorying the life. The only way out is strike a balance and no one knows what is the balance. It is question of life.