Most scientists now agree the Earth is gradually warning, and that this is largely due to the so-called greenhouse effect, caused by increased amounts of the gases such as carbon dioxide which trap energy from the Sun in the atmosphere.

But take the discussion a even stage further - how bad is warming likely to be? What should done about it? - and much of the consensus vanishes.

The United Nations warns that if nothing is done, temperatures will rise by anything up to nearly six degrees Celsius by the end of this century.

Many say the signs of warming are already here.

British author Mark Lynas spent three years travelling the globe to research a book on global warming, High Tide, and says he was "shocked" to see melting glaciers, Pacific islands disappearing beneath the waves and deserts eating up northern China.

"I think I probably didn't appreciate the scale of what was happening before I wrote the book. You often think things will be perhaps less dramatic than you expect, but for me it was the reverse," he says.

The way forward is far less clear.

At one extreme, a small number of experts actually believe it is too late to reverse the phenomenon, notably scientist and author James Lovelock, famed for developing the pioneering "Gaia" theory, which sees Earth as a single, if massively complicated, living organism.

Rather than drawing up treaties to curb greenhouse gas emissions, Lovelock argues, governments must simply prepare for climate change - for example deciding where to re-house millions of people whose cities have flooded.

"When you model the earth as if it was a responding system, the one thing that comes out is that it is quite prone to make sudden jumps from one state to another. It is beginning to look more and more as if it's already started moving in the direction of one of these jumps," he says.

"Therefore very little that one does will have any impact on the outcome."

More mainstream environmental groups insist this is too gloomy.

"Personally, I don't think it's too late, I think we're getting near to the point where we will be unleashing catastrophic damage but there's nothing to be gained by assuming the worst," says Tony Juniper, director of Friends of the Earth.

"If there is still a window of opportunity - and the science says there is - we should be using it. What we have to do is not only bring these challenges to people in a forceful way but with a sense of optimism, let people know that there are things that can be done and it doesn't have to wreck their quality of life."

There is also a third view, albeit one also rejected by most mainstream environmentalists.

Danish academic Bjorn Lomborg uses his background as a statistician to pore over environmental data and what it means for the world.

His conclusions, published in 2001 book The Skeptical Environmentalist, were surprising, and, opponents insist, dangerously misguided.

Lomborg believes that while global warming is a reality, it should be viewed not as an unmitigated disaster but a more complex phenomenon which will affect different regions in different ways.

Global warming "will probably be a slight net benefit" in some northern industrial nations such as his home country, he argues, with more deaths being saved from reduced winter cold than would be claimed by summer heat.

"This doesn't mean I'm saying we should have global warming, but it's important to realize that we are not likely to make good judgements unless we have all the facts, and not just the facts that go to one side of the argument," he says.

Lomborg also argues that global efforts to tackle greenhouse gas emissions are misguided, given that the billions of dollars that would be spent could be put to much better use on more immediate problems such as poverty and AIDS.

"The bottom line is that global warming is happening, it will be an important issue over the next 100 years.

"The point is, in 2100 we're not try to save a poor Bangladesh, we're trying to save a fairly rich Holland. You've got to ask yourself: where is the need the biggest?"

What do you think about global warming and how to deal with it?

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Name: Lisa
Location: Vancouver, Canada

Global warming is the new buzz term of the moment, mainly perpetuated by the media serving the governments to hold the general population responsible, and to make us feel guilty for the mess created by the large corporations.

The real issue is the growing population and the rampant consumerism that goes with it. The solution for the existing problem of pollution and garbage disposal, created by ever growing number of people, has been around long for quite a while. There are plenty of solutions such as solar batteries, geothermal energy, 'green' buildings, wind power, the energy of tides, electric powered cars, Japanese models of garbage and waste disposal.

Instead of land fills they extend their land mass by using garbage, and the methane released for heating the homes. China has realized that garbage is the greatest and the cheapest resource in the world, and are now building their economy based on it. The Thames river in London had a massive clean up and is a model used now in India for cleaning up of Ganges and Yamana rivers.

So people, use Google to find the information, and your critical thinking to analyze it.

Name: Frederick
Location: Germany

The world needs a cleaner source of energy other then what we are depending on now. The question is what will this new source of energy be? I have heard that synthetic fuels can cause more of a problem then what we are dealing with now. To switch from what we use today will be extremely expensive. This is probably one of the reasons why the big corporations are so reluctant to change. They only way to get that change is for the governments to enforce strict rules and penalties that will make them do it. Hydrogen is a better source I think, to power automobiles. Auto manufacturers and the governments should start getting more serious about that and start building the engines and infrastructures to support them.

Name: Denis
Location: Seattle, USA

If there is no effort to reduce the number of people in the world, (and I see no efforts being made) then how can we avoid the inevitable?

Name: Nitin Tomer
Location: Raipur, India

Global warming is the result of humans living without an understanding of nature. Now we need to fix the role of humans and the needs of humans. We need to take it as a mission to live harmoniously with nature, otherwise we just postpone the problem.

Name: Tabitha
Location: Malaysia

I may not a scientist but what I do know is that we human beings are the people that have caused global warming. Our greed for money has taken its toll on the environment and now, we are suffering the consequences. I believe global warming can be at least minimized if every human in this world still has a heart for Mother Nature.

Name: Muriithi Muthike
Location: Central Province, Kenya

As much as we in developing nations are pointing a finger at developed economies, we're no better either. In our own ways, we are accelerating the change in climate.

In Kenya for instance, how do you account for the $500 million charcoal industry? This is a massive destruction of our forests! We have to look for alternative sources of fuel while at the same time reforestation to mitigate the negative impacts of global warning.

Name: Brenton Miller
Location: Bakersfeild, California, U.S.

I have one question: Despite all the scientific advancements, why do we see so much suffering all around us?

Name: Michelle Boyer
Location: Tucson, Arizona, U.S.

In regards to global warming, we should no longer be asking who is responsible, but how we can begin to reverse the effects.

Every individual, no matter where they are located, can help reverse these effects if they become aware. Simple acts can go a long way, so rather than place blame, let us all become aware. If politicians, and other country officials, opened the floor to their citizens and addressed the facts, rather than hide them, we could all change.

Perhaps we will never be able to reverse all of the changes brought on by global warming, and perhaps we will only delay now inevitable consequences, but isn't even the slightest bit of progress better than nothing? All I hear and see, even on these comments, are individuals pointing their fingers.

Stop pointing, and start impacting. If you think you can change something, then get out there and do it, like I strive to do. Inform others, write to Congress; do whatever is in your power, no matter how small an act, or you're not helping either.

Global warming exists. What we need now are solutions, global and individual solutions, not rash blame-games.

Name: Unwana Udomah
Location: Nigeria

I strongly suggest that the issue of global warming should be addressed by the developed countries before the underdeveloped.

Name: Renato Santos
Location: Manila, Philippines

The measures being undertaken by the international community in addressing global warming appear to be more preventive and reductive rather than corrective.

The problem with this strategy is that it merely delays the inevitable but does not avert this rapidly unfolding catastrophe. I am not a scientist nor an expert in this field, but in this age of modern science and advancement, there must be a better alternative.

Are the effects of global warming truly irreversible? Can't we develop technology to drain the "greenhouse" gases, render them harmless, disperse it somewhere safe or convert these gases to their basic elements (recycle), or better yet harness it as some form of energy source?

The international community should invest in researching and developing technology to at least attempt accomplishing that objective. These suggestions I know are overly simplistic and unrealistic but with so much as stake, anything is worth a try. And sometimes even the most complicated and effective solutions spring forth from the sillies ideas.

Name: Saurabh Chauhan
Location: Nagpur, India

I totally agree that global warming is due to human activities. Each and every person now has an obligation to use natural resources like water, fossil fuels, electricity very cautiously so that this disaster can be postponed. Global warming is another name for negligence and human greed.

Name: Francisco Muro
Location: Buenos Aires, Argentina

Concerning the global warming problem, I see a lot of people working on the issue of how to stop it but I heard of nobody framing a Plan B. What if the planet finally warms up and water level goes up?

Thinking out loud, the first idea that comes into my mind as a solution is, how can the amount of the Earth's surface containing desert benefit from the melting of the Poles? The amount of water frozen in the Poles is comparable to the amount of desert on the Earth's surface. Considering this, it is not difficult to think that all the water can be redirected towards desert areas where lack of water is a major problem for a lot of species.

This comment does not attempt to minimize the efforts of those who work to stop global warming, but considering the way the problem is being attended, I only try to bring a new issue into the debate table.

Name: Dedsetmad
Location: Geelong, Victoria, Australia

Without an ecology we cannot have an economy. FACT. The industrialization of the world has bought about changes to this planet that man doesn't have the time to do anything about let alone know how to fix.

Our seabirds have gizzards stuffed with pieces of broken plastic (which they cannot pass) slowly poisoning them to death; ocean bottoms are layered with detritus of man-made plastic bags hovering at all depths silently imitating food for a whale or dolphin to choke on; millions of liters of our excrement are mixed with industrial toxicity pumped into our oceans every hour; forests that have taken billions of years to build our atmosphere are being ripped from the face of the Earth; the steady addition of toxins to our air and water by governments testing atomic bombs and monolithic corporations who answer to nobody 'cause everybody's faceless, dumping shit on whoever and whatever they please; CEO's smiling in church as their lawyers clean the mess.

Name: Zane
Location: U.S.

Whether or not global warming is taking place, It is still taking affect on our communities. People are arguing, politicians aren't listening, and this whole thing is blown out of proportion.

Now if global warming is taking place it will not "jump from one state to another" as said by Mr Lovelock. This is because the Earth is not a responding system. It is simply a planet with life sustained by energy from the Sun. Therefore the changes in weather and climate will occur gradually, as they currently are.

There is nothing that we can do about it considering that we are not the main cause of green house gases. That is the work of Mother Nature.

Name: Larry Peter Makanjuola
Location: Switzerland

My wish is for people to stop destroying, killing and make a plan for the new generation to make this world a better, safer place to live.

Name: Dorothy Shapiro
Location: New York state, U.S.

My wish is for CNN to put forth programs that deal with conservation. I have 12 grandchildren and hope they will have a future. By urging your viewers to recycle, conserve and reuse, I believe it will make a difference. Thank you.

Name: John DaGloria
Location: Ontario, Canada

The debate on whether human activity is causing global climate change is all but finished. Few dispute this and even US President George W. Bush has admitted the problem exists. Despite this overwhelming evidence, mankind is unwilling to take decisive action to alter what could eventually cause enormous damage to our natural world and ourselves as a result.

Perhaps we think that our money and ingenuity will shield us from these consequences. Perhaps we feel our scientists will come up with a last minute solution, or maybe we just believe it will only affect the poor countries far away from our sheltered paradise. Or perhaps we have just lost our minds and are all blindly racing towards an uncertain future too preoccupied with our day to day responsibilities.

Name: Jothi Narayanan
Location: Palakkad, Kerala, India

To combat global wareming, we must create real awareness of it in humankind, starting from primary school. We must also have population control and use less fossil fuels

This must include reducing the number of car users and having more public transport users, and making nations accountable for global warming by their use of fossil fuels in the name of luxury life.

Name: Susanna Wen
Location: Ipswich, Suffolk, U.K.

I'm doing a project on air quality at school and I may not be very official or important but I am learning the seriousness of it all and the fact that it's me and my future children and grandchildren who are going to have to face this.

Name: Clarissa Gotsch
Location: Germany/U.S.

I believe that global warming is an entirely too big of a problem. It is causing glacier melting, changes in ocean temperatures and changing temperatures in the atmosphere.

I believe that if something is not done as soon as possible we have much more to lose than we think. There is way too much that we take for granted in the world today to realize what we could possibly lose.

Not everyone is going to cooperate when it comes to changing lifestyles in order to save our planet. But if the majority of the people make an effort, some changes can be made before it is too late.

Research should concentrate on finding new ways to produce energy without harming our environment, such as solar or wind power. Mandatory recycling would reduce the production and waste of natural resources. Creating cars and vehicles that don't produce harmful emissions and release them into the atmosphere would be a big help as well.

The world is connected in a big circle. It is not possible for someone to do something without having some sort of consequence, good or bad. That is what is happening with our planet right now. Humans didn't look at what the consequences to their actions might be. Now we have to take some action and clean up what we have done.

Name: Scott Sutterfield
Location: Grand Rapids, Michigan, U.S.

SPS (solar-powering satellites) are the solution. The sun is our savior, but we have to reach for the sky in order to harness its healing power.

Name: Grimdol Ida
Location: Edinburgh, Scotland, U.K.

As a scientist, I can see why we are concerned by global warming. The future holds many changes in temperature but also in ecological effect. Resources on Earth have been far too easily available to us, but now that is about to change.

It is time that we begin to look at new perspectives in how to harness fuels for the future that are compatible to our environment and these can be collected from 'light'. Light is one of the most powerful elements to life and it can provide for life. Light can be manipulated for power and it can be released back to earth from above, by satellite, after refinement on the planet surface. This is the 're-bound effect'. CO2 gas can absorb energy from light and this is one of the elements which can be used in harnessing effect for our future fuel supply. We must use the natural elements that are around us to save this world from disaster.

Name: Amaobidike Chukwuma
Location: Enugu, Nigeria

There is a saying in my country that says if an individual who goes to the stream to fetch water makes the water unclean, he or she will have to drink it like that.

If the world keeps on waving the issue of global warming aside, then it is clear that in the future we have to live with it like that. So I think it's high time we act to save our environment, this involves everybody at all levels collaborating to save our world.

The funny part of this whole situation is that the developed countries, that are contributing almost 80% of these industrial gases, are able to reduce emissions but they keep procrastinating.

Name: Padma Radhakrishna
Location: India

Global warming is a reality. Though you cannot stop it altogether, You can make an effort to reduce the addition of greenhouse gases by way of using non-conventional means.

Name: Bobbie M. Hardesty
Location: Houston, Texas, U.S.

I firmly believe that what is causing the warming is not above the ground but under it. I think we can expect volcanoes to become more active with new ones added. I think the center of the earth is warming at the core and like a bubbling liquid is beginning to send off bubbles of heat and air. So, I may be wrong but what if my theory is right?

Name: Lindsay
Location: Chicago, U.S.

Global warming will one day destroy our planet. Our air will be unbreathable and basically all life will cease to exist on Earth. Ways to stop global warming: STOP POLLUTION.

Name: Sandy
Location: Armenia

I think pollution carries much of the blame for global warming. Emissions form automobiles, power plants, chemical industries etc. are doing their best to pollute the air.

Every year we are dealing with so many catastrophes, all due to global warming. I think this world is going one way -- a dead end from which no one will return.

Name: Nina Morrison
Location: Austin, Texas, U.S.

Each individual, every person must make changes in their lives. If we can individually change we can make a very big difference. We must act and do what we can.

We must make changes in what we see as important in our lives. The way we have lived for the past 50 years cannot continue. What we think that the next 75-100 years may be different, very different.

We must realize that this planet is important and the environment has been abused, possibly beyond repair, but we still must try. I'm sad for my kids and grandkids. I'm worried and personally have made changes and still have many more changes to make.

Name: Harold D. Pierce, Jr.
Location: Burnaby, British Columbia, Canada

Prior to 1900, the amount of carbon dioxide was ca. 0.0280% by volume for mid-latitude dry air at sea level and 0 deg. C. Presently, this value is about 0.0380%. Essentially, the composition of the atmosphere has remained unchanged for the last 100 years.

Yet, the climatologists are claiming and trying to convince us that the carbon dioxide produced by the combustion of fossil fuels is 'the' major greenhouse gas that is responsible for the present trend of global warming. This claim is incorrect. There is one and only one major greenhouse gas and that is water vapor. So what the guys up to?

The 1997 Kyoto accord was scheme devised by all the envious, jealous, and mean-spirited countries of the old world to embarass the United States, an economic, social and political juggernaut that just keeps rolling on down the highway.

The officials and scientists of these countries knew with absolute certainty that the US would never ever agree to the terms of this accord. Consequently, they have an on-going excuse to bad mouth US.

The scientists also knew that the reduction of greenhouse gas emissions to the recommended levels was impossible for almost all countries.

There is also a sinister and hidden agenda in the Kyoto accord. By producing all the gloom and doom scenarios with their computers, the scientists have ensured that governments will shower them with copious amounts of research funds for the foreseeable future. In his farewell address to the nation, the late President Eisenhower warned that the scientific and technological elite are a threat to public policy and the political process and we should be wary of them.

There are a number of unknown factors that could contribute to global warming. The influence of undersea volcanic activity is unknown. Since 1990, over 50% of the world's forests have been cut down to make way for agricultural uses, urbanization, lumber, pulp, etc.

Forests are like umbrellas that keep the earth cool. Clean air has less particulate matter which has a cooling effect due to reflection of sunlight. Since 1990, where has all the billions of pounds of minute black heat-absorbing particles of rubber and asphalt gone? The simple answer is everywhere.

Name: Yook Seung Jong
Location: Seoul, South Korea

here are many method to solve this problem. First of all, we have to reduce car use.

Name: Dave Councilman
Location: St. Louis Park, Minnesota, U.S.

As a parent I hope for a future world with minimal complications from global warming. While I believe it is caused by the actions of man, I say that even if you don't believe this we need to try and do something about it for future generations.

It is selfish of us to live for ourselves and the present only. I don't see people changing soon, but I hope that we can look forward and for the good of all rather than living in the "Me NOW" times we have.

We need to start by using our voices as voters to elect leaders that are future thinking and world-view centered.

Name: Adrian
Location: Melbourne, Australia

Pollution will lead to several health problems and will eventually deplete the ozone layer, causing us to be unprotected from the harsh sun. We will have to always wear a hat and stay indoors.

Name: Duncan McRoberts
Location: Medicine Hat, Alberta, Canada

It's not "just" global warming from fossil fuels... there's also global dimming.

It's a 98% certainty that mankind will not abandon its fossil fuel addiction. Humanity's use of fossil fuels is 33% responsible for the change in global weather. There are three other human factors that contribute the remaining 67%: deforestation at 13%; all human pollutants at 14%; and global urbanization at 40%.

We passed our last window of opportunity to redress this problem in 2003; nature's backlash has already established momentum, and its upcoming effect upon human civilization from 2008-2010 could be compared to a 10.7 earthquake in Los Angeles.

Name: Solomon Ademosu
Location: Lagos, Nigeria

Theories, assumptions, predictions etc... will fail. Nothing man can do will stop the impending doom awaiting mankind in the nearest future.

Name: Olga
Location: Moscow, Russia

People are a malignant growth on the body of the Earth, that will kill it and then will die itself.

Name: William Porter
Location: Merritt Island, Florida, U.S.

A great part overlooked is the fact that oil insulates the globe. The Earth's inner heat is also being released. It would be extremely wise to consider replacing the oil taken with some type of insulation to stop the release of heat and deformation of the globe -- nitrogen and water to re-establish pressure are not insulating the inner core heat.

Telsa tried to give us a way to conduct electricity freely. His work is available and should re-introduced. Cold fusion isn't being taken as a true alternative. It should be and funded immediately.

Name: Derek
Location: England

Let's hope that our jump towards man's extinction from the face of the Earth through global warming comes before we humans manage to escape this once unpolluted planet to pollute other unpolluted planets.

We should aim to bring about our extinction through global warming as swiftly as possible so that nobody is left to suffer, blame, or remember the reason for our sudden disappearance from the face of the Earth.

In the meantime, let us enjoy the time we have left.

Name: Kim
Location: West Virginia, U.S.

It may be too late to do much about global warming at this late date. If U.S. citizens reduced their consumption of resouces to compare more favorably with the rest of the world, maybe, but I can't see that happening in my lifetime. As long as there is profit to be made from oil, there will be excess consumption in the U.S.

Name: Nathan Wittry
Location: Austin, Texas, U.S.

I believe a large part of the skepticism stems from a saddening distrust of science, born from generations of arguments against evolution. If the science behind the theory of evolution cannot be trusted, why should one trust the science of global warming?

People are further misled when those in power perpetuate this blind distrust. Countering theories with other theories, supported by evidence of course, plays an important role within the scientific community, but doubting a scientific consensus simply because of stubbornness endangers the foundations of all scientific conclusions. If you can doubt the majority results of one experiment, why not doubt them all?

The science behind global warming is simply undebatable. The evidence has revealed itself all over this planet.

It is no longer a theory, nor is it a leap of faith. Instead of debating whether or not global warming is happening, we should be pressuring politicians to pay attention to scientists' warnings. Those in power ignored the warnings about New Orleans and just look at the result.

Unfortunately, Hurricane Katrina revealed another great weakness in humanity -- selfishness. Nations and humans alike mirror this personality trait, and only disaster seems to open the eyes and reveal the pink elephant in the room.

I'm hoping against hope that we can win the fight against scientific distrust and selfishness before another disaster attempts to teach humanity the lesson it can't seem to learn.

Name: Shyam Krishna Malaviya
Location: Kolkata, India

The damage from global warming will simply be irreversible if corrective steps are not taken within the next 20-25 years.

With the massive excavation of minerals, coal, oil, gas, etc etc, we are like greedy men sitting on top of a building, who don't realize that they are removing the main foundations bit by bit.

Name: Brother Warren
Location: Las Vegas, Nevada, U.S.

It's sad how environmentalists can bury themselves under so much ignorance.

More so-called greenhouse gases come from volcanoes and natural sources than mankind and the animal world can generate.

Overplanting a particular area is as bad as a manufacturing plant. Comparing mankind to Mother Nature is like comparing the Earth to the sun! Man is almost as unimportant to the Earth as the Earth or moon is to the sun.

Name: Alan Reid
Location: Gloucester, U.K.

Even though I think the argument that we are in an odd section of a cyclical weather pattern that runs over years or even centuries holds a lot of weight, there are simply too many people on our planet using too many resources - and it's getting worse...!

Name: Pat Lynch
Location: San Juan del Sur, Nicaragua

I think the entire issue is being deliberately obscured by the term "global warming." The issue isn't about climate change. The Earth has gone through periods of natural warming and cooling and will continue to do so.

The real issue is pollution. There is no debate that greenhouse gases are air pollution. The debate shouldn't be about global warming. It should be about curtailing pollution. The entire planet agrees on this.

Leave the global warming debate out of the equation and we would have broad consensus to curtail air pollution.

Global warming may or may not be our fault, but air pollution certainly is. If we stop air pollution, we also stop our adding to greenhouse gases. Whether or not this would stop global warming is another issue. Cleaner air would definitely be the result.

Name: K. S. Raghu Kumar Gadiyaram
Location: Hyderabad, India

I agree with Pat Lynch -- we are currently enjoying the fruits of nature and so must do something in turn to preserve it.

In my opinion, pollution shares much of the blame for global warming. Emissions form automobiles, power plants, chemical industries etc. are doing their best to pollute the air.

I don't say that we must halt all these processes, just use more non-conventional methods.

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