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Compare opinions of world leading experts and influencers.

Is global warming caused primarily by humans?

Since the industrial revolution, humans have been emitting greenhouse gases that the Intergovernmental Panel on Climate Change (IPCC) believe are responsible for Global Warming. While the majority of climatologists agree with the IPCC's conclusions, skeptics suggest that the IPCC's climate models are flawed and that recent climate changes should be attributed to natural causes.

Implications to Other Questions


Experts and Influencers

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Agree
Experts In Climatology


Intergovernmental Panel on Climate Change    (IPCC) Scientific Body formed by U.N.
Mostly Agree
Most of the global average warming over the past 50 years is very likely due to anthropogenic GHG increases and it is likely that there is a discernible human-induced warming averaged over each continent (except Antarctica).
01 Jan 2008    Source


Wallace Broecker    Climate Scientist, Coined "Global Warming"
Agree
...the present cooling trend [as of 1975] will, within a decade or so, give way to a pronounced warming induced by carbon dioxide. By analogy with similar events in the past, the natural climatic cooling which, since 1940, has more than compensated for the carbon dioxide effect, will soon bottom out. Once this happens, the exponential rise in the atmospheric carbon dioxide content will tend to become a significant factor and by early in the next century...
08 Aug 1975    Source


Michael Oppenheimer    Physics Professor, IPCC Lead Author
Agree
There's little doubt that humans are largely responsible for the warming that has occurred over the last few decades. And even more important, there's a certainty that if the greenhouse gases build up at current rates, that the Earth will warm over the century to levels that haven't been seen in a million years. Over the past ten years or so, so-called skeptics have raised a number of objections, but these have been knocked down by research scientists...
05 Oct 2006    Source


Ian Enting    Physics Professor, IPCC Lead Author
Agree
I'm acting as a reviewer for the latest last little bit of the IPCC reports, and you actually do get to see this vast body of evidence in appallingly large detail (and massive amounts of trees have gone into it) and that's what you can't explain away. So it tends to be people who focus on one very tiny aspect and say there could be other causes, but when you look at the evidence as a whole or even a large part of it, then I don't think there's anything in these [skeptical] arguments at all.
14 Jul 2007    Source


Experts In Physics


Joseph Romm    Physicist, Environmentalist, Writer
Agree
The science isn't settled -- it's unsettling, and getting more so every year as the scientific community learns more about the catastrophic consequences of uncontrolled greenhouse gas emissions. The big difference I have with the doubters is they believe the IPCC reports seriously overstate the impact of human emissions on the climate, whereas the actual observed climate data clearly show the reports dramatically understate the impact.
27 Feb 2008    Source


Steven Chu    US Energy Secretary, Nobel Laureate in Physics
Mostly Agree
There are stronger and stronger indications that global warming is happening, that it's caused by humans, and its consequences are looking more and more ominous. You can draw a parallel to the early days of [research into] cigarette smoking, the '50s and '60s, where scientists said, "Hey, there seems to be a link between lung cancer and cigarette smoking."
30 Sep 2005    Source


Experts In Science


David Attenborough    Botanist, Writer, Nature Documentarian
Agree
I'm no longer sceptical. Now I do not have any doubt at all. I think climate change is the major challenge facing the world. I have waited until the proof was conclusive that it was humanity changing the climate. The thing that really convinced me was the graphs connecting the increase of carbon dioxide in the environment and the rise in temperature, with the growth of human population and industrialisation.
24 May 2006    Source


Michael Shermer    Scientist, Skeptic, Author
Agree
As an undergraduate in the 1970s, I learned (and believed) that by the 1990s overpopulation would lead to worldwide starvation and the exhaustion of key minerals, metals and oil, predictions that failed utterly. Politics polluted the science and made me an environmental skeptic. Nevertheless, data trump politics, and a convergence of evidence from numerous sources has led me to make a cognitive switch on the subject of anthropogenic global warming.
01 Jun 2006    Source


Robin Hanson    Economics Professor
Agree
CO2 is clearly way up (~30%) over 150 years, and rising fast, mainly due to human emissions. CO2 is denser than its been for a half million years. ... The match between recent warming and CO2 rise details is surprisingly close, substantially raising confidence that CO2 is the main cause of recent warming. ... This adds support for mitigation. ... It was mostly skeptics bending my ear, and skeptical arguments are easier to find on the web. But for now, the other side has convinced me.
30 May 2009    Source


Experts In Law


Barack Obama    United States President
Agree
There may still be disputes about exactly how much we're contributing to the warming of the earth's atmosphere and how much is naturally occurring, but what we can be scientifically certain of is that our continued use of fossil fuels is pushing us to a point of no return.
03 Apr 2006    Source


Hillary Clinton    US Secretary of State 2009-, Democrat
Agree
At the top of the world [the Arctic], you hear stories -- affirmed by decades of scientific investigation [on anthropogenic global warming] -- of changing weather patterns, melting ice, retreating glaciers, unprecedented wildfires, eroding coasts, and invasive species. You can see the evidence with your own eyes. There are no climate change skeptics inside the Arctic Circle.
05 Nov 2007    Source


Experts In Politics


Al Gore    Environmentalist, Former U.S. Vice President
Agree
We face a true planetary emergency. The climate crisis is not a political issue, it is a moral and spiritual challenge to all of humanity.
12 Oct 2007    Source

Sub-Arguments Of This Expert:
Is the IPCC objective?
   Agree

John McCain    U.S. Senator, Republican
Agree
The world is already feeling the powerful effects of global warming, and far more dire consequences are predicted if we let the growing deluge of greenhouse gas emissions continue...
24 Apr 2007    Source


Experts In Feminism


Amanda Marcotte    Blogger, Author, Feminist
Agree
Calibrating historical weather trends is tricky stuff, and there are different conclusions from different measurements. But taken together, they all show a single, compelling trend: global warming. Global warming denialists are using exactly the same technique as creationists: zeroing in on relatively minor, technical, inside baseball disagreements about exact data to create confusion with the public that doesn’t understand science.
13 Mar 2010    Source


Neutral
Experts In Climatology


John Christy    Climatology Professor, Former IPCC Lead Author
Neutral
Atmospheric carbon dioxide continues to increase due to the undisputed benefits that carbon-based energy brings to humanity. This increase will have some climate impact through CO2's radiation properties. However, fundamental knowledge is meagre here, and our own research indicates that alarming changes in the key observations are not occurring.
13 Nov 2007    Source

Sub-Arguments Of This Expert:
Is the IPCC objective?
   Disagree

Experts In Politics


Mitt Romney    Former Governor of Massachusetts
Neutral
I believe that climate change is occurring — the reduction in the size of global ice caps is hard to ignore. I also believe that human activity is a contributing factor. I am uncertain how much of the warming, however, is attributable to factors out of our control.
02 Mar 2010    Source

Sub-Arguments Of This Expert:
Are the causes of climate change well understood?
   Disagree

Disagree
Experts In Climatology


Roy Spencer    Meteorologist
Mostly Disagree
I predict that in the coming years, there will be a growing realization among the global warming research community that most of the climate change we have observed is natural, and that mankind’s role is relatively minor.
22 Jul 2008    Source

Sub-Arguments Of This Expert:
Is the IPCC objective?
   Disagree

Experts In Physics


S. Fred Singer    Head of NIPCC, Astrophysics Professor
Mostly Disagree
The gap between the satellite observations and existing theory is large enough to cast serious doubt on all computer-model predictions of future warming. Whatever the cause of the gap, we cannot rely on GCM (General Circulation Models) forecasts of future warming. (GCMs are not even consistent with each other; their temperature forecasts vary by some 300 percent.) Until GCMs become validated by actual climate observations, they should not be used as the basis for policy.
01 Apr 1999    Source


Jasper Kirkby    Particle Physicist
Mostly Disagree
[Sun and cosmic rays] will probably be able to account for somewhere between a half and the whole of the increase in the Earth's temperature that we have seen in the last century.
23 Feb 2007    Source


Denis Rancourt    Physics Professor
Disagree
The atmospheric greenhouse effect is a well known natural phenomenon, mostly caused by atmospheric water vapour, that keeps our planet warm and habitable whereas (anthropogenic = human-made) global warming refers to a small extra greenhouse warming (0.5-1 C/33 C; 1-5 %) allegedly arising from an increase in atmospheric concentration of the minority greenhouse effect gas CO2 (carbon dioxide) – the later increase in turn possibly arising from fossil fuel burning.
27 Feb 2007    Source

Sub-Arguments Of This Expert:
Does atmospheric CO2 cause significant global warming?
   Mostly Disagree

Experts In Science


Khabibullo Abdusamatov    Astronomer
Mostly Disagree
By the mid-21st century the planet will face another Little Ice Age, similar to the Maunder Minimum, because the amount of solar radiation hitting the Earth has been constantly decreasing since the 1990s and will reach its minimum approximately in 2041.
01 Aug 2007    Source

Sub-Arguments Of This Expert:
Have solar cycles significantly affected earth's recent climate?
   Mostly Agree

B.P. Radhakrishna    Geologist, President of the Geological Society of India
Disagree
The causes of these changes are cosmogenic...
23 Aug 2007    Source

Sub-Arguments Of This Expert:
Have solar cycles significantly affected earth's recent climate?
   Agree

David Bellamy    Botanist, Documentarian
Disagree
The link between the burning of fossil fuels and global warming is a myth. It is time the world's leaders, their scientific advisers and many environmental pressure groups woke up to the fact.
09 Jun 2004    Source


David Kear    Geologist
Disagree
Personal beliefs on climate change and rising sea levels should be delayed until just one of the many predictions made since 1985 on the basis of carbon additions to the atmosphere comes true.
13 Apr 2007    Source


Robert Carter    Marine Geophysical Professor
Disagree
With the complete discrediting of the ‘hockey stick’ curve of recent temperature change (McIntyre and McKitrick, 2003, 2005; Wegman, Scott and Said, 2006) that was the icon of their report, the IPCC case for dangerous human-caused warming now rests only on ambiguous anecdotal evidence, unvalidated computer models and misleading attribution studies (IPCC, 2007).
02 May 2007    Source


Tom Segalstad    Geology Professor
Disagree
Most leading geologists, throughout the world, know that the IPCC's view of Earth processes are implausible if not impossible.
07 Jul 2007    Source


Miscellaneous Experts


Monte Hieb    Mining Engineer
Mostly Disagree
So far the signal of a discernible human contribution to global climate change has not emerged from this natural variability or background noise.
19 Dec 2006    Source


Disagree
There are no experimental data to support the hypothesis that increases in human hydrocarbon use or in atmospheric carbon dioxide and other greenhouse gases are causing or can be expected to cause unfavorable changes in global temperatures, weather, or landscape... ...We also need not worry about environmental calamities even if the current natural warming trend continues. The Earth has been much warmer during the past 3,000 years without catastrophic effects.
01 Jan 2007    Source


Experts In Politics


Sarah Palin    Former Governor of Alaska (Republican)
Disagree
A changing environment will affect Alaska more than any other state, because of our location. I'm not one though who would attribute it to being man-made.
29 Aug 2008    Source

Sub-Arguments Of This Expert:
Is the IPCC objective?
   Disagree

Michele Bachmann    US Politician, Republican
Disagree
Let’s just go to a fundamental question. Carbon dioxide, Mister Speaker, is a natural byproduct of nature. ... [Yet] carbon dioxide is portrayed as harmful! ... Human activity contributes perhaps three percent of the three percent. In other words, human activity is maybe 3 percent contributing to the 3 percent of carbon dioxide that’s in Earth’s atmosphere. It’s so negligible — it’s a fraction of a fraction of a fraction of a percent — that it can hardly be — be quantified.
22 Apr 2009    Source


Experts In Mathematics


David Evans    Mathematician
Disagree
I am a scientist who was on the carbon gravy train, understands the evidence, was once an alarmist, but am now a skeptic. The whole idea that carbon dioxide is the main cause of the recent global warming is based on a guess that was proved false by empirical evidence during the 1990s... In science, empirical evidence always trumps theory, no matter how much you are in love with the theory.
23 Mar 2011    Source


Encyclopedia


Conservapedia    Christian Encyclopedia
Disagree
The Climategate emails and climate data have been the subject of intense debate, calling to question assumptions on anthropogenic (man-made) global warming; evidence revealed told the truth about man-made global warming: it's a fraud.
03 Apr 2010    Source

Sub-Arguments Of This Expert:
Is the IPCC objective?
   Disagree

Ambiguous or Flip-Flop
Experts In Media


Time Magazine    Popular Magazine
Agree
Be worried. Be very worried. ...Pump enough CO2 into the sky, and that last part per million of greenhouse gas behaves like the 212th degree Fahrenheit that turns a pot of hot water into a plume of billowing steam.
03 Apr 2006    Source


Time Magazine    Popular Magazine
Disagree
Whatever the cause of the cooling trend, its effects could be extremely serious, if not catastrophic. Scientists figure that only a 1% decrease in the amount of sunlight hitting the earth's surface could tip the climatic balance, and cool the planet enough to send it sliding down the road to another ice age within only a few hundred years.
24 Jun 1974    Source



Comments

Add Your TakeOnIt (click to expand, no login required)
0 Points      MTC      23 Feb 2013      Stance on Question: Agree
The scientific consensus is clear: global warming is happening and is primarily human‐caused.


0 Points      MeGustaLetran      18 Mar 2013      Stance on Question: Agree
humans are the no.1 reason why global warming exist in our time humans use many things that cannot be recycled and dumps these items wherever they want. this is primarily the reason why there is global warming people needs to act now if they want to stop the increasing problem about global warming. if we don't act now there will come a time when it is to late to stop global warming and all of the trash that we threw away will come back to us and do harm to us.



1 Point      Nashhinton      19 Nov 2011      Stance on Question: Mostly Agree
It is a known scientific fact that global warming occurs because the earth occasionally goes through warming and cooling periods. But the thing that bothers me is that the earth's temperature has been substantially rising ever since the beginning of the industrial revolution, which makes me speculate if the burning of fossils fuels or the emission of certain chemicals are causing the dramatic increase in the earth's temperature. However, I am unsure if human activity is a major component for causing global warming, but I'm going to believe that it is on the basis of my current understanding of the evidence. I believe that more scientific evidence needs to be evaluated and tested to see if the majority of global warming is caused by human activity. The right wing's hatred for science and their constant conspiracy theories should be avoided if we are to fully comprehend the dire consequences and nature of global warming. We should continue to promote scientific exploration and not believe that global warming is a conspiracy created by Al Gore. Scientific progress is based on empirical research and continual testing. It's not based on a total rejection of the scientific evidence. We should ignore the Republican Party's hatred for science if we are going to fully save humanity from destroying itself. In the mean time, we should start by using alternative and renewable energy.

My beliefs on what I've read so far about global warming is that global warming is mostly caused by human activity.


0 Points      gibson teodoro      17 Mar 2013      Stance on Question: Agree
Pollution is the biggest man made problems. And it comes in any shape and sizes. Another major man made cause of Global warming is population. More peolpe means more food, and more methods of transportationn. Also mining and oil allows methane to escape.



0 Points      blacktrance      10 Feb 2011      Stance on Question: Agree
The consensus is quite clear.


2 Points      Benja      22 Jun 2010      Stance on Question: Mostly Agree
The consensus of climatologists is clear. While one can somewhat glibly declare that the consensus is irrelevant, and demand clear-cut scientific tests a layperson can personally understand before accepting a hypothesis, it is not rational to do so. When a plethora of tests are required to test a hypothesis, and domain expertise is required to understand and synthesize those tests to attain the likelihood of that hypothesis, the rational thing to do is to outsource the assessment of that hypotheses to domain experts. This reasoning is described in more detail here.

When a scientific consensus exists but clear-cut tests do not, the matter is not settled, but the onus shifts to the contrarians to present a consistent set of claims that refute the prevailing view. If they fail to so, a rational layperson should side with the consensus. At the top-right of the page you can see a break-down of the major contentions of this issue, phrased as yes-no questions. I found these questions to be the most revealing:

Are the causes of climate change well understood?
Do negative feedback loops mostly cushion the effect of atmospheric CO2 increases?
Does cosmic radiation significantly affect earth's climate?

Through examining these arguments, I've come to the belief that the claims of climate skeptics are rife with inconsistency. Perhaps the most egregious inconsistency, is claiming Earth's climate is too complex to understand, while simultaneously claiming that climate change is very likely caused by nature. Such inconsistencies are exactly what you'd expect from contrarians whose skeptical thought passes through a polarized filter. These inconsistent claims are promoted by leading climate skeptics with impressive scientific credentials such as S. Fred Singer and Roy Spencer. S. Fred Singer is a particularly important figure because he heads the NIPCC (Non Governmental International Panel on Climate Change), a coalition very representative of the skeptical viewpoint.

I believe scores of bright climatologists with idealistic truth-seeking tendencies that override their fear of peer-suicide have had ample opportunity to provide convincing refutations of AGW. Given the amount of time I've spent so far seeking such refutations, I'm getting discouraged that any solid objections exist. (To address concerns I may have conducted a motivated search, I actually started out leaning towards the skeptical side.) Given the consensus and the lack of a coherent objections to that consensus, I believe AGW is likely to be true. However, I leave the door open to the possibility that AGW is false so long as we await clear-cut tests.


-2 Points      Anonymous      28 Jun 2010      Stance on Question: Mostly Disagree
I believe that a large proportion of the 'facts' presented by the followers of the climate change religion are baed on poor science carried out by a troupe of self-interested scientists whose livelihood depends on them finding in favour of the greenies.

Anybody that pretends to understand the causes and effects of the earth's temperature and climate well enough to prescribe a remedy that will even partially halt the rise in temperature is a liar and their science is not to be trusted.


1 Point      Benja      28 Jun 2010      General Comment
This is an ad hominem attack - and not even a good one at that! Go here if you want to rationally debate climate science bias. Also, this comment doesn't address any of the content of the comment it replies to, and in fact doesn't even add any new content to the debate. It's also trivially reversible (the bits I've altered are in bold):

"I believe that a large proportion of the 'facts' presented by the followers of the climate denier religion are baed on poor science carried out by a troupe of self-interested scientists whose livelihood depends on them finding in favour of the oil companies."

"Anybody that pretends we don't understand the causes and effects of the earth's temperature and climate well enough to prescribe a remedy that will even partially halt the rise in temperature is a liar and their science is not to be trusted."

C'mon! As a rebuttal, it gets an F. As an essay it would get an F. As an insightful comment about any aspect of this issue it gets an F. As representative of the opinions of a good deal of "skeptics"? It gets an A.




0 Points      the27th      09 May 2010      Stance on Question: Mostly Agree
It seems there's more evidence for this than the contrary.


-1 Point      DGwartney      06 May 2009      Stance on Question: Agree
Two major mechanisms for abrupt climate change will reside with changes in the atmosphere and oceans. Additional CFC’s in the atmosphere, including carbon dioxide and methane, have the potential of sharply raising the earth’s global temperature. The possible effects of climate forcing positive feedbacks is that as greenhouse gases increase, they can in turn cause increased heating. It is then assumed that the increased heating will continue along with even more increases in CFC’s. There are many other theories that carbon dioxide may have an irreversible change on our climate. The oceans have the ability to absorb the excess carbon dioxide, but if the numbers continue to rise the absorption may become saturated. This would lead to warming of the deep ocean warming as well as atmosphere. There is a possibility of increased frequency of El Niño events. This could even lead to a pole ward shift of the Hadley Atmospheric Circulation Cell. Such a drastic shift could force areas such as the American Southwest to become deserted wastelands. Essentially, if ocean and atmospheric oscillations are disturbed or updated due to increased heating, the global climate change has the potential of being disastrous.


1 Point      Jack      08 May 2009      General Comment
I'm a bit confused here... Carbon dioxide and methane aren't CFCs. They contain neither chlorine or fluorine. In any case, CFCs, or chlorofluorocarbons, are notorious for ozone depletion, rather than global warming, and have been phased out of production since the Montreal Protocol...


-1 Point      Tyler      08 May 2009      Stance on Question: Agree
I do believe global warming is primarily caused by humans. Based on the greenhouse effect, this is a natural phenomenon enhanced by human activites. Greenhouse gases from human activities additionally increase the average temperature. These gases include carbon dioxide, methane and ozone. This can result in climate change, a change in rainfall patterns, melt ice in the polar regions, and cause a rise in sea levels. Human activities such as the burning of fossil fuels, deforestation, and landfills are some examples.


-1 Point      Peace, Hope, Love      29 Jan 2010      Stance on Question: Mostly Agree
I too believe global warming is mostly caused by humans. Even though the climate changes have gone through a cycle for the past millions of years, it was never like this before. I was talking with one of my friends, and we were "debating" about global warming. He said it is nearly a cycle and that is why the dinosaurs are gone, that we are just here in their places. something has to be in charge right? Anyway, it was a good point but, the dinosaurs didn't fill the air and waters with pollution to get what they wanted. As selfish humans, we do what it takes to get what we want, no matter the cost. Many things can be said about this situation, but, no matter ones opinion, our world is at danger. we need to take a minute and look where we are at. Do you really want your great-grand kids to have to take care of and fix our mistakes? Should further generations have to pay with their lives because of our flaws?




0 Points      Oluseun Idowu      05 May 2009      Stance on Question: Mostly Agree
We need to consider activities leading to increase in atmospheric greenhouse gases (GHGs) when talking about global warming as a result of anthropogenic effects (human induced). We know that atmospheric GHGs act as umbrella not allowing heat to escape from the lower part of the atmosphere. It is therefore reasonable to say that global warming is primarily caused by humans if we are able to argue that human induced activities are contributing to increase atmospheric GHGs. A very good example to consider is the atmospheric CO2 concentration level as a GHG. We know that most of the atmospheric carbon sources are a result of human-induced activities. For example; burning and combustion of fossil fuels, cement manufacturing, deforestation, biomass burning and land use changes. In fact, every living organism including soils, natural gas, peat and coal contains carbon, and depending on the role they play, they could be a carbon source or a carbon sink. The argument therefore is that as human activities increases the CO2 level of the atmosphere, a GHG concentration in the atmosphere is increased, and consequently the globe gets warmer. If we think about the rapidly growing global population, growing global industrialization (especially with little regard to the environment), and other human activities that tends to restructure the atmosphere system, and thereby increasing the GHG concentrations, we would be able to clearly link global warming with human activities.


-1 Point      Barry      27 Apr 2009      Stance on Question: Mostly Disagree
I remember learning in my geology class that the Earth has changed the location of the poles numerous times. This point was used explain why we are getting oil from under the Arctic Ocean where it was once warm enough to spawn life.

Global warming is another example of the Earth changing and science trying to explain it. Science is now being used for a political purpose and this means, money and power are influencing people's views.

The bottomline is we humans need to be responsible to have a "light footprint" as part of our Stewardship of the Earth. Politicians need to pass laws to protect the Earth (gaining support by fear is not the answer). The reason to pass the laws is it is the right thing to do.


0 Points      Terry      24 Oct 2011      General Comment
Hey Barry... It was never "warm" in the arctic nor the antarctic. The plates of the Earth have simply moved around and they were once located closer to the equator and were thus warmer.