Here’s an interesting fact. If you ask climatologists, paleoclimatologists, meteorologists, atmospheric chemists, atmospheric physicists, geophysicists, oceanographers, and those that study aeronomy, 98% agree that climate change is real and 90% of scientists from all fields of science in general believe it is real. 97.1% of all scientific papers which take a position on climate change agree that it is real, is caused by humans and serious. Survey finds 97% of climate science papers agree warming is man-made

If you ask the average non scientist American it varies between 40-60% believe it is happening. Recently one climatologist explained his reasoning for why he thinks most Americans are out of tune with what most scientists believe. He said it is the media’s tendency to have “expert guests” on shows and always put one that supports the idea on TV and one that doesn’t. If they wanted it to be accurate they would pick Ten scientists at random to debate the issue and odds are at most 1 would disagree that global warming is a reality the rest would tell you it is happening and we need to take serious steps to prevent it from getting worse…

Scientific opinion on climate change >> http://en.wikipedia.org/wiki/Sci…

No scientific body of national or international standing has maintained a dissenting opinion;

Wikipedia has a good list of scientific organizations and references to studies and surveys you can look up and see that there is a clear consensus and for 90%+ of scientists to agree on something like this, we should be taking this FAR more seriously than most people do.

EDIT: See the comments for some great discussions on the related science.
EDIT2: It’s great to see so much interest in this question here around Earth Day let us hope we do not forget these things as the year wanes on. Combating Climate Change requires commitment to big and little changes and we can all do our part. From recycling, low flow shower heads and LED light bulbs to supporting stronger anti-pollution laws we can all make improvements.
EDIT3: Article on a recent study that shows how recent weather trends can not be explained by random chance alone. If global warming was not happening the recent series of events year after year could not be explained as mere spikes in probability. Each event would be a 1 in a million year event instead they are happening repeatedly decade after decade. http://www.washingtonpost.com/op… Written by the study author. James E. Hansen directs the NASA Goddard Institute for Space Studies.
EDIT4: Adding from the comments to the answer..

Comment

Joshua Theobald
I’m really astonished that somehow humans are solely responsible for “global warming” let alone a significant contributor. We’ve been burning fossil fuels, clearing trees and the like for 2000 years. The Sahara Desert isn’t claimed to be a man made disaster, nor the global cooling of the 1970’s. We can’t predict the weather, we just report what is observed to be heading in one direction or another. Until we can grasp our complex environment and start understanding all the factors that go into warming and cooling of our planet, I prefer not to be blamed as the major contributing factor to our planet warming up for a couple hundred years.

My Reply

We may not like it. We may not want it. We may feel powerless to stop it but that does not mean we are not responsible for it. I am partially responsible for my local landfill, nuclear waste produced in powering my home and many other icky things and so are you, this is true if we like it or not.

We produce 26 Gigatons of CO2 per year and we do not absorb any.

That’s 29,000,000,000 tons of CO2!

58,000,000,000,000 pounds CO2 PER YEAR! No joke. It’s an unfathomable number. We are producing that much of a GAS per year. When you put it in that perspective it’s pretty scary.

The environment naturally absorbs and produces CO2. With 6 billion people we are enough to offset a natural balance that never had to deal with us before.

About 40% of human CO2 emissions are being absorbed, mostly by vegetation and the oceans. The rest remains in the atmosphere. As a consequence, atmospheric CO2 is at its highest level in 15 to 20 million years. A natural change of 100ppm normally takes 5,000 to 20.000 years. The recent increase of 100ppm has taken just 120 years.

We are just enough to be too much.

Man-made CO2 emissions are much smaller than natural emissions. Consumption of vegetation by animals & microbes accounts for about 220 gigatonnes of CO2 per year. Respiration by vegetation emits around 220 gigatonnes. The ocean releases about 332 gigatonnes. In contrast, when you combine the effect of fossil fuel burning and changes in land use, human CO2 emissions are only around 29 gigatonnes per year. However, natural CO2 emissions (from the ocean and vegetation) are balanced by natural absorptions (again by the ocean and vegetation). Land plants absorb about 450 gigatonnes of CO2 per year and the ocean absorbs about 338 gigatonnes. This keeps atmospheric CO2 levels in rough balance. Human CO2 emissions upsets the natural balance.

http://www.skepticalscience.com/…

Not a perfect list but a good start to simple changes to be more responsible.
http://www.50waystohelp.com/

Global warming is actually happening.  Here is the theory behind it:

1.  There is CO2 gas, the direct result of people burning things like fossil fuel, which has become a larger constituent of the Earth’s atmosphere than it was previously.

2.  The molecules of this gas are large enough to scatter heat back to the Earth’s surface — so the Earth is less effective at radiating heat out into space.  Any molecule which has three or more atoms is large enough to scatter heat.  (According to a lecture I heard by the Nobel Laureate Sherwood Rowland, who has just left us.)  This heat scattering is called the ‘greenhouse effect’ in popular and some scientific literature.

3.  Heat drives storms.  Storms are based on convection — the movement of material based on its density difference compared to its surroundings — which, in the case of the near atmosphere, is akin to saying based on heat — since heat sets up great density differences.  The rock record shows a huge amount of extra weathering during the most recent previous warming period where the climate change happened as rapidly as in our current world (Paleocene-Eocene Thermal Maximum).  Cores drilled and retrieved show a hugely thick layer of sedimentary rock formed from weathered continental material correlated with the last global warming period.  That weathering was most likely due to storm activity.  Big storms are incredibly dangerous.

Here is the paper I’ve referenced about the increase in weathering during the last period of warming:
Productivity feedback did not terminate the Paleocene-Eocene Thermal Maximum (PETM)

Here are some observations supporting the reality of global warming.  These are from the following NASA website:
http://climate.nasa.gov/evidence/

1.  Sea Level Rise: Global sea level rose about 17 centimeters (6.7 inches) in the last century. The rate in the last decade, however, is nearly double that of the last century.

2.  Global Temperature Rise:  All three major global surface temperature reconstructions show that Earth has warmed since 1880. Most of this warming has occurred since the 1970s, with the 20 warmest years having occurred since 1981 and with all 10 of the warmest years occurring in the past 12 years. Even though the 2000s witnessed a solar output decline resulting in an unusually deep solar minimum in 2007-2009, surface temperatures continue to increase.

3.  Warming Oceans:  The oceans have absorbed much of this increased heat, with the top 700 meters (about 2,300 feet) of ocean showing warming of 0.302 degrees Fahrenheit since 1969.

4.  Shrinking Ice Sheets:  The Greenland and Antarctic ice sheets have decreased in mass. Data from NASA’s Gravity Recovery and Climate Experiment show Greenland lost 150 to 250 cubic kilometers (36 to 60 cubic miles) of ice per year between 2002 and 2006, while Antarctica lost about 152 cubic kilometers (36 cubic miles) of ice between 2002 and 2005.

5.  Declining Arctic Sea Ice:  Both the extent and thickness of Arctic sea ice has declined rapidly over the last several decades.

6.  Glacial Retreat:  Glaciers are retreating almost everywhere around the world — including in the Alps, Himalayas, Andes, Rockies, Alaska and Africa.

7.  Extreme Events: The number of record high temperature events in the United States has been increasing, while the number of record low temperature events has been decreasing, since 1950. The U.S. has also witnessed increasing numbers of intense rainfall events.

8.  Ocean Acidification: Since the beginning of the Industrial Revolution, the acidity of surface ocean waters has increased by about 30 percent. This increase is the result of humans emitting more carbon dioxide into the atmosphere and hence more being absorbed into the oceans. The amount of carbon dioxide absorbed by the upper layer of the oceans is increasing by about 2 billion tons per year.

There are lots and lots of things a person and communities can do to reverse this trend.  Personally, I think the easiest thing is for people to get serious about planting trees, while larger entities are sitting on their hands deciding what to do.  Trees sequester CO2, and I would think that a concerted effort has some good potential to reverse the global warming trend.  Here are some other things I favor:

1.  Industry might make more of an effort to use bio-based plastics and composites.  (Basically, making plastic from things like soy or corn oil instead of petroleum.  Growing crops pulls CO2 out of the atmosphere.)  Who wouldn’t like to combat global warming by generating plastic to be thrown out?  That’s something we’d all be good at doing!

Here is a link to books on bio-based plastics and composites.
http://www.amazon.com/s/ref=nb_s…

2.  Governments and science might start looking at creating extra ice in the polar regions, to create a heat sink, artificial ice fields.  This is feasible — but the infrastructure to transport water for deposition (and later freezing) on high-latitude land in the Fall or early Winter would be significant.  The extra ice would serve to sequester some of the heat from the atmosphere in the Springtime, as the ice fields melt.  I do not know if it is possible to trap all of the extra heat in this fashion, but it is an interesting proposition.  Artificial ice fields would have a stabilizing effect on global temperatures.

3.  Stop burning fossil fuels.  These put extra greenhouse gases into the atmosphere as the endproduct of combustion, and this is a source of carbon which had been previously sequestered in the ground.  It is much better not to introduce any of this fossil carbon into the atmosphere — and make fuels from plants or other means.  Research on alternative energy is progressing well.  I’ve got a paper published on catching lightning for alternative energy.  There are many, many more untried or up-and-coming technologies and ideas for energy.

4. Do anything that strikes your fancy which will result in sequestering CO2 and other greenhouse gases.  Give more cut flowers, use wood which would otherwise be trashed for a project — anything which pulls CO2 out of the atmosphere.

5. Put yourself squarely behind wanting to make this change.  It will happen if enough people get active.  Some solutions (like switching from petroleum to bio-based plastics) are technological — beyond most peoples’ immediate reach.  But others, like planting a tree every two weeks, as weather permits, are reasonably achievable.

Finally, governments need to put plans in place for how to deal with more catastrophic storm events.  Municipalities ought to have new plans drawn up, with contingencies for several major storms, back-to-back, and start training for this kind of emergency.

I’m not sure I like the tone of my answer — much too didactic.  Forgive me!  Thanks for the question!

This answer was originally written for a question that made the following point:

A very interesting paper claims that the human contribution to CO2 and greenhouse emissions is puny compared to nature. Events such as volcanoes and geysers release far more.

It is easy to be confused about the human contribution to CO2 and whether it is puny compared to nature. What is important is how much greenhouse gas builds up in the atmosphere, not how much flows in and out of the atmosphere.

In the Carbon cycle there are huge flows of carbon to and from the atmosphere (we call this the carbon ‘flux’). For instance, microbes alone create about 60 billion tonnes of carbon that enters the atmosphere. In contrast, the flow from humans is indeed tiny (about 9 billion tonnes a year).

Here’s the thing though: the emissions from microbes is matched by absorption elsewhere but most of the carbon we add to the atmosphere stays there. Some man-made CO2 is absorbed by the oceans and some of it is absorbed by plants but over half of stays in the air, and it builds up over time. 30% of the carbon dioxide in the atmosphere today was put there by us.

Think of a powerful tap pouring water into a bath in which the plug is out. The water pouring out is matched precisely by the water pouring in – the bath is in equilibrium even though the ‘flux’ is high. Now imagine adding just a trickle from another tap – a tiny amount compared to the main tap. It may take a while, but eventually the bath will overflow. That’s what happening with greenhouse gases in our atmosphere.

This ‘tiny trickle’ isn’t actually so tiny. Today it is over 330 tonnes of carbon every second (or in other terms 1,200 tonnes of carbon dioxide every second or 107 million tonnes every day). This short animation shows what that looks like:

To bring home the significance of what we are doing to the atmosphere think of the air in the room you are in right now. If you could extract the man-made carbon dioxide from the air in the room you would get several gallons of it.

In the air in a small room 20′ x 20′ x 9′ (6.1 x 6.1 x 2.7 metres) there will be 3.2 US gallons of man-made carbon dioxide (12.2 litres). That to me is quite a significant amount of pollution! It’s only because it is odourless and invisible that we don’t worry about it.

UPDATE

A commenter (Ben O’Regan) made the following point:

“… lets think about what really matters – how much difference does that make to the optical properties of the atmosphere.  As CO2 absorbs a narrow band of infrared radiation and the atmosphere is already virtually opaque to that band – adding a little more CO2 isn’t really going to change the climate significantly is it?”

The answer to his question is: yes it will. Adding CO2 to the atmosphere has already changed the energy budget (how much energy escapes into space) and the build up of heat energy is already changing the climate.

TL;DR: The Earth radiates infrared radiation into space. Much of it gets through the atmosphere (which is not as opaque as Ben O’Regan claims) but carbon dioxide prevents some of it getting away, which is good because it keeps the Earth warm. Excess carbon dioxide in the atmosphere means that less infrared escapes into space, which means that heat energy stays at the surface of the Earth. The excess heat caused by the excess carbon dioxide in the atmosphere is equivalent to every man, woman and child on Earth having 82 hairdryers (2 kW) blasting away all day and night.

Longer, more detailed answer:

To understand the difference greenhouse gases make, let’s get down to basics. The Earth radiates infrared radiation because all warm things ‘glow’. If they are hot enough (about 800 °C) they glow ‘red hot’. That is, at 800 °C objects are so hot that they glow with visible light. At lower temperatures you can’t see the glow but you can sometimes feel it.

The average temperature of the surface of Earth is only 15 °C, which is not hot enough to glow with visible light but is hot enough to glow with infrared radiation. Electromagnetic radiation is characterised by its wavelength – shorter wavelengths are more energetic. Red light has a wavelength of about 0.75 micrometers (0.75 millionths of a metre). The symbol for a micrometer is µm because µ is the greek letter ‘mu’ and means ‘micro’.  Infrared wavelengths that the Earth emits are about 10 micrometers (10 µm) which is 10 millionths of a metre. The atmosphere is by no means opaque to the infrared light at these wavelengths:

The diagram shows how transparent Earth’s atmosphere is to radiation of different wavelengths (source: Atmosphere of Earth)

The graph above is a picture of how the Earth ‘glows’. It shows how much energy escapes from an object (any object) at the same temperature as the Earth. It also shows how the escaping energy is shared between different wavelengths of radiation. The peak is at 10 µm and most energy is carried away at wavelengths between 5 µm and 30 µm. Carbon dioxide absorbs infrared in two broad bands centred at about 5 µm and 15 µm, and so any carbon dioxide in the atmosphere catches much of the escaping glow.

How much difference does this make? (Radiative Forcing)

But the question is, how much difference has this CO2 made? How much of the heat energy that would have escaped into space is being trapped on Earth? The technical term for this is ‘radiative forcing’ and it is measured in Watts per square metre. That is, radiative forcing is the extra energy that an average square metre of Earth receives every second because of the extra greenhouse gases in the atmosphere.

By looking at all the published estimates and selecting the most robust of them, the IPCC concluded that radiative forcing had reached a level of 2.29 Watts per square metre by 2011. This is an estimate, but the data is good enough to say that the true figure is somewhere between 1.13 Watts per square metre and 3.33 Watts per square metre.https://www.ipcc.ch/pdf/assessme… (page 13)

2.29 Watts is about the same energy as a tiny torch (flashlight) that you might keep on a keyring. It doesn’t sound very much, but you have to remember that we are talking about alot of square metres (the Earth’s total surface area is 510 million square kilometres).

To put it another way, the radiative forcing in 2011 was equivalent to having an array of 1 kW fan heaters spaced 11 metres apart that covers all land on the planet. Picture it – a fan heater every 11 metres everywhere, in all directions from coast to coast. To put it another way, it is equivalent to every man, woman and child on Earth having 82 hairdryers (2 kW) blasting away all day and night for all time. So yes – adding CO2 to the atmosphere really is making a significant difference to the climate.

OK, here goes.

The thesis that global warming is a result of man-made CO2 is open to legitimate criticism.   We live in a culture where such skepticism is essentially considered heresy; this is both an unscientific and undemocratic trend.

First, let me be ad hominem.   Anthropogenic global warming is refuted by MIT atmospheric physicist Richard Lindzen.   Dr. Lindzen is a nationally famous luminary in his field, often called “The Dean” by his colleagues across the country.    You can hear him speak on the topic here –

Second, let me try to be factual.   Al Gore loves to go around the country showing this graph, which displays global temperature along with atmospheric CO2 levels.  (This information is gleaned from ice core data in the arctic, see National Climatic Data Center) :

Yellow is temperature.   Red is C02 in the atmosphere.

Wow.   Sure looks like CO2 drives climate change.    It even appears that CO2 is the onlydriver of climate change.   So we’re done – anyone who denies this is crazy, on-the-take from big oil, stupid, or all three.

As Columbo used to say in the old TV-series, “Um … Just one more thing before I go, ma’am.”

Isn’t a little weird that CO2 is the only driver of climate change?   Water vapor retains more heat, as does methane and sulfur dioxide.    Strange.
But never mind that.   Let’s take those two graphs and plunk them on top of each other.   Superimposing them gives :

OK, look really carefully.   CO2 (blue) is lagging slightly behind temperature (red.)   The average lag is 800 years.

A cause must precede an effect.   The ice cores show temperature driving CO2 levels, and not the other way around.

And more than this.   Look at the big red dip, around 125,000 years ago.   Even though CO2 is at a peak level – the temperature dives, dragging CO2 down with it.

Put simply – CO2 is not seen to drive climate change in the past.

You might protest – but we *know* CO2 is a greenhouse gas.   If we put more in the atmosphere, the temperature *must* increase.   It’s simple physics.

Too simple.   The earth’s climate is a complex system, involving feedback loops and mathematically “chaotic” behavior (Chaos in the Atmosphere).   If we simply calculate the effect of CO2 added by humans to the atmosphere we get less than a degree Celsius of warming.

The thesis that the added CO2 will result in several degrees of warming is based on models which invoke feedback loops and “tipping points”.   This is very tricky business; very sensitive to assumptions and omitted dynamics (like cloud cover, ocean currents, etc.)   We haven’t got this complex mechanism figured out.   We don’t know how to model it.    This is what happened when we tried :

So the projections don’t seem to work.   It’s only 10 years – fair enough.   But our models didn’t exactly get a standing ovation from nature.

To recap : We don’t see CO2 driving climate change in the past.  Our attempt to predict it in the future failed.   Oh – and what are temperatures doing dropping anyway, given that man-made CO2 emissions are at their highest ever?

“And one more thing, ma’am.”

Take a look at the first two graphs.   Those warm spikes – don’t they seem to be pulsing ?   Like there is some sort of rhythm involved?   We might be so reckless as to use the termcyclic?

Last graph, I promise :

Oh.   That top line is the shape of the earth’s orbit.   The earth’s 0rbit changes shape in a rhythmic cycle, going from nearly circular to more eliptical and back again.   These are called Milankovitch cycles.

The earth’s orbit doesn’t give a crap how hot or cold earth is or what’s in its atmosphere.   Nothing is going to push it around.

And this graph shows two things : Ice ages recur about every 100,000 years, just as the earth’s orbit starts to become less eliptical.   And … we are right on schedule for another one.

So Dr. Lindzen – “The Dean” is not crazy.   “Deniers” – can we call them skeptics? – are by no means crackpots.    They should be heard.   The future of mankind may depend on it.

If they are right – a new ice age is coming no matter what we do.   So we must prepare for it; build lots of nuclear reactors, reduce global population, develop ways to produce food in cold climates.    By running around chasing CO2 we are solving the wrong problem.

Our engines will be silenced soon enough by glaciers.

Quora seems to be a highly educated community, and I imagine most reading this thread already understand that GW is real and is a big concern.

As others have pointed out, the interesting question is why many people in the U.S. do not realize this.  Until voters in the U.S. widely recognize global warming as a serious threat, things are going to continue to get worse, at terrible risk to humans and risking virtually permanent damage to the biosphere.

I was formerly a hard-line conservative who was skeptical about climate issues, (until some smart and very patient people showed me the corrupt roots of my beliefs).  Reflecting on that part of my life, I think I know a part of the answer to this.

I think some of the biggest issues are bias that comes from the media and self-confirmation bias.  When you’re a conservative and a disproportionately large portion of your life communication is listening to clowns like Rush Limbaugh, or talking with other conservatives, etc, it seems unthinkable that the huge wall of people and information that backs up your beliefs doesn’t have at least some reasonable grounding.  It just feels too ridiculous, and creates too much cognitive disonnance, to think that all of the “backing” that you have behind your skeptical GW beliefs is groundless.

As best as I can tell, these kinds of opinions are generally only influenced slowly.  I think education can bring people to realize that something’s wrong with the way their current beliefs are justified — but only a small number of people will ever achieve this.  Otherwise, I think that its important that one not be too harsh or vehement in disagreeing with GW skeptics.  Rather, I think a calm, simple statement of disagreement does a better job at influencing them over the long term (and not causing cognitive backlash that re-inforces existing beliefs).  However, people do slowly change their beliefs when they see that a majority of people around them disagree with them, so its important to let people know that your opinion is that GW is real and that being skeptical of it in the way that many people are is indefensible.

Further, in conversations with a GW skeptic, I think its highly counter-productive to talk about details about the science, examples of weather patterns, etc.  In that arena, people who deny GW can generally come up with several scientific “counterexamples” or other garbage, but without being a scientist or being intimately familiar with the subtle problems with this kind of argument, you aren’t going to get anywhere.

In the end, very very few people come to a belief about GW actually do so through first-hand evaluating of the scientific data.  Rather, what separates a GW skeptic and someone who understands that GW is true, is that the latter understands what sources or people are worthy of their trust, and which are bogus.  It is NOT about understanding science properly.  Until GW skeptics can see that they’re being deceived by dumb or untrustworthy people, they’re stuck.

“Hey, I never said the global warming hoax wasn’t elaborate…”

One could add the thousands of scientists who are part of the conspiracy, all the faked temperature measurements, the insurance companies who are lieing to their investors about future costs, the fraudulent measurenents of sea levels….

The overwhelming consensus among climatologists is that climate change is real and it is at least partly human caused. Most of these climatologists would go further and say it is probably mainly caused by human activities.

You can find a lot of articles out there by people who do a pretty good job sounding like they know what they’re talking about, saying it’s all a scam, but for every one article like that, there are probably 100 from reliable sources saying the opposite. There are hardly any actual scientific, peer reviewed articles that conclude global warming is not real and not human-caused.

There are a lot of corporate interests spending a lot of money to try to create confusion to delay governmental action that could impact the profits they make related to pumping damaging greenhouse gases into our atmosphere.

If a doctor told you you have cancer and you need surgery soon, you’d be wise to get a second opinion. If you went to 30 doctors, and 29 said you need the surgery, but one said he didn’t think you needed it, would you go with the 29 or the 1?

Here’s are some articles you might look into:
Scientists More Certain Than Ever on Climate Change, Report Says
Skeptic scientist: Global warming is real
Is there a scientific consensus on global warming?
The Social Cost of Carbon: Setting the Record Straight Ahead of Today’s House Hearing
How Accurate are Future Projections of Climate Change? A Look at Past IPCC Reports Provides Some Answers
Gas Ceiling: Assessing the Climate Risks of an Overreliance on Natural Gas for Electricity
Top scientists urge cap on carbon emissions to limit climate change
‘Uncomfortable’ climates to devastate cities within a decade, study says
Through the Looking Glass: Climate Change Denial, Conflict of Interest and Connecting Science to Policy

The answer is Yes and the scientific consensus is very strong. In a seminal article, Naomi Oreskes conducted a systematic review of 928 scientific papers in peer reviewed journals and found that not a single paper disagreed with the consensus position that human activities cause climate change. (The Scientific Consensus on Climate Change). Link to video lecture with Naomi Oreskes:

(This answer was moved after a different question was redirected here.)

No, it’s not a hoax.

Where do you look for the heat?  In the oceans.  The oceans hold a lot more heat than the atmosphere.  That’s where the heat is going.

Source: Ocean heat flux – Arctic Sea Ice

See also Climate Reality | Facebook

The question was, “Is global warming really happening?” Yes, the best information as I understand it is that surface temperatures on land and in the oceans are rising slowly and steadily. You can have a debate about the possible causes, but it is true that the warming correlates with a rise in the concentration of CO2 in the atmosphere.

As for my specific country, Canada, it is warming. Still, in particular winters, it can still be very cold. However, our weather service uses a 20-year rolling average for “normal” temperatures, and every few years, they must bump that up slightly to the new, warmer average. In British Columbia, we have pine beetle infestations of the forests that are thought to be due to the new, warmer habitat being more hospitable to the beetles. In Alberta, as elsewhere in the world, glaciers have been been in retreat since the mid-to-late 1800’s. In more and more parts of Canada, we have new concerns with Lyme disease due to the warmer temperatures affecting the spread of the ticks that carry the disease. In the Arctic Ocean, the situation is complex, but ice-free periods are becoming more frequent and longer http://www.sciencepoles.org/arti…

So I would say that my part of the planet is warming, and that I think that it is most likely anthropogenic, caused by humans using fossil fuels. You might have an alternative explanation, but it is warmer.

Not very many people, including political conservatives, disagree that climate is changing and that there is some sort of warming going on.

The issue that is being debated is the cause of this change.

One group believes that human industry over the past 150 years or so has resulted in a massive increase in the amount of carbon dioxide (CO2) in the atmosphere. It is known that CO2 is a ‘greenhouse gas’, that is, one that traps heat in the atmosphere. Due to the presence of large amounts of CO2, temperatures on the Earth must increase and that the increase is going to lead to severe environmental problems. This belief, known as Anthropogenic Global Warming (AGW), leads to certain ideas about how to solve the problem, including the reduction of CO2 output by factories, power plants, etc.

Another group believes that there may be causes other than AGW. Among these are solar cycles, natural variation in the climate over extended periods, cloud cover, etc.

Skeptics point to less-than-transparent reporting on global warming on the part of some climate researchers. They note that climate modeling is poor and does not entirely account for a plateau in temperature rises that has occurred over the past decade or so. The cynical of the critics also point to the possibly venal motivation of some climate scientists, noting that there’s big money to be made — in the form of grants and government spending — in calling for urgent action.

If climate change is driven by human activity, then it is quite possible that changes in that activity can reverse or at least halt the changes. If climate change is driven by non-human events, then forcing expensive changes in human behavior will have no effect, other than to make people poorer.