Convince me about anthropogenic climate change?

Question

I'm a sceptic. Convince me that it's humans causing it, and that it's going to cause major problems in the future.

I approach with an open mind, though I don't promise to change my opinion.

Bob's answer was the sort I'm looking for - sourced, links, didn't scream about it, etc. Didn't convince me (none of the links gave me anything new), but it was argued well, so it's the best so far.

Bob's answer was the sort I'm looking for - sourced, links, didn't scream about it or expect capital letters to suddenly enlighten me, etc. Didn't convince me (none of the links gave me anything new), but it was argued well, so it's the best so far.

Answer 1

Sheer volume of CO2 in atmosphere is currently more than 40% higher in the last 40 years than it has EVER been in the tens of thousands of years that are traceable in polar ice core samples. In another 40 years, at current rates of emission, that percent will increase to some 250% higher than ever. This is called statistical significance, when eons of history show a predictable historic cap that is only broken in our lifetimes in a period that correlates with exponential expansion of population and global GDP.

Answer 2

All right, how much heat does an engine block produce. How much CO does a car exhust put out.

There are 50 million vehicles registered in the State of California alone.

A rough estimate of the world puts the auto at 2-3 billion, in use at least 4 hours a day every day

You're telling me that is not affecting the envornoment to any degree

There is SMOG in inland Alaska.

Where do you think ACID RAIN comes from.

Where do you think PCBs come from.

GE has to set up a plant to clean up the Hudson River from all the damage it did in the last 75 years.

That's ONE PLANT, ONE COMPANY

Do you recall that Lake Erie was once declared "dead."

I'll be quite frank with you, it's not going to kill you, but don't have any kids for your great great grand kids are going to be in big trouble if we don't fix things up

Right now as you sleep CANCER CAUSING hydro carbons are in the air in parts per million from car exhust.

These are SLOW toxins that will cut your life down a little, could give yo emphysiema, possibly lung cancer in older age.

If none of this bothers you, I expect you to also don't get involved in the "second hand smoke" cigarette movement, for it's almost as harmful.

If you want scientific data, it's out there and there is NO KNOWN NATURAL CAUSE

The SUN is not changing

We don't have a lot of volcanos going off

There is no NATURAL set of factors to point to and say THAT IS WHAT IS CAUSING IT

We can only assume it is man's machines raisting the heat of the air, putting chemicals into the air, soot into the air.

And, by the way, we are also killing the oceans algea and cutting down the rainforrests

I'll give you a hint, cars don't make air, plants do.

Answer 3

Can't do it in a few words of brilliant argument. You'll have to do a little work and check my references and my data. That's how science works.

The report below is based on a mountain of peer reviewed data. On page 4 it lays to rest the idea that this is solar variation. That is 0.12 watts per meter squared while man caused warming is 1.6 watts per meter squared.

http://www.ipcc.ch/SPM2feb07.pdf

This says it isn't volcanoes.

http://www.geology.sdsu.edu/how_volcanoes_work/climate_effects.html

This shows how man is overcoming nature. The little teeth are plants trying to regulate CO2 by the "carbon cycle". The big surge upward is us, burning fossil fuels containing carbon the natural cycle buried over many thousands of years.

http://scrippsco2.ucsd.edu/graphics_gallery/mauna_loa_record/mlo_record.html

What I don't have a simple reference for is the fact that the present warming is far faster than any previous natural cycle. But it's why climatologists reject that idea.

This shows clearly that the vast majority of scientists do indeed support the fundamental ideas of global warming; it's real, it's us, and it's a problem.

http://www.sciencemag.org/cgi/content/full/306/5702/1686

Do you respect any of the guys below? They don't get their science from Al Gore, they get it from the best scientists in the world.

"The science of global warming is clear. We know enough to act now. We must act now."

James Rogers, CEO of Charlotte-based Duke Energy.

"The overwhelming majority of atmospheric scientists around the world and our own National Academy of Sciences are in essential agreement on the facts of global warming and the significant contribution of human activity to that trend."

Russell E. Train, Republican, former environmental official under Presidents Nixon and Ford

"We simply must do everything we can in our power to slow down global warming before it is too late. The science is clear. The global warming debate is over."

Arnold Schwarzenegger, Republican, Governor, California

"Our nation has both an obligation and self-interest in facing head-on the serious environmental, economic and national security threat posed by global warming."

John McCain, Republican, Senator, Arizona

"These technologies will help us become better stewards of the environment - and they will help us to confront the serious challenge of global climate change."

President George Bush

If someone recommends the movie "Swindle" read these:

http://en.wikipedia.org/wiki/Martin_Durkin_(television_director)

http://news.independent.co.uk/environment/climate_change/article2355956.ece

EDIT: OK , I haven't "convinced" you. But let me ask you this. You have to bet a hundred pounds that global warming is mostly natural or mostly anthropogenic. Even money bet, to be decided 20 years from now (the money earns interest). Which side do you take?

By the way, check out Trevor's website below. It has some interesting graphs about warming over the last 1000-2000 years.

http://profend.com/global-warming/pages/establish.html

They've been criticized because the data is "noisy" but the trend line seems to be the most plausible outcome. Which is why the National Academy of Sciences basically agreed they're correct and the IPCC put them in their latest report, which is actually a very conservative document because it's the product off a large committee.

By the way, I've laid off on effects because that's more controversial. But watch for the IPCC report coming in the next few months on this. It will be scary, I predict. And it will justify the idea that we really need to do something about this, because it will be cheaper to slow it down than to deal with full blown effects.

Answer 4

OK.

1. Post 9/11 air traffic dropped to near zero. During that time atmospheric measurements showed that the ecosystem started to recover (ozone hole got smaller, GHG content dropped).

2. The excess energy of global warming is expressed first as bad weather. We see that happening, we are breaking records left and right. Each one degree C rise in the temperature of the oceans is equal to the energy of 1.3 BILLION one MegaTon atomic bombs. That is for each one degree rise, which has already happened ... and we are expecting a 3-5 degree rise in the next few decades.

We are exitting winter and entering tornado season. I predict billions of dollars of damage across the continental US due to high winds and flooding again this spring. That is a major problem don't you agree?

Answer 5

I say we just nuke the Antarctic and get if over with. Iced tea, anyone?

Answer 6

It's a good question and with the amount of conflicting arguments from both sides it's no wonder some people are sceptics or don't know what to beleive.

Below is part of an answer I gave, you'll need to refer to this page http://answers.yahoo.com/question/index;_ylt=AjTAC2NwO2_f2Nik.XFGkJ7sy6IX?qid=20070312182624AAmYqxF&show=7#profile-info-b8030aa120d2bc03c6b9d54372abcdb9aa for the rest of the article and the citations.

The full answer I gave is in the process of being converted into a website, it's not finished but the parts of most interest to you are now online... http://profend.com/global-warming/pages/intro.html - best read online as it includes graphs, links, more info etc.

2 – IS GLOBAL WARMING REAL
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We know the world is warming up, on this the scientists are agreed. The question isn’t so much whether the world is warming but what’s causing it, how much is attributable to natural causes and how much is attributable to human activity.

AS A NATURAL PHENOMENA
There’s no disputing that the world is warming up, this is a long established fact. Since the creation of Earth some 4.5 billion years ago there have been many warming and cooling cycles. Over the course of the last 18,000 years the world has been in a warming cycle and has heated up by approximately 9°C (16°F) [C3] this warming brought about the end of the last ice age [S2].

On a much larger time-scale the world is in a general cooling phase and has been for about 50 million years [C4], this in itself is part of a much larger cycle of long term cooling and warming [C5].

AS A MAN-MADE PHENOMENA
If there were no life on Earth it would still be warming. What we’ve seen in the last couple of hundred years is an unprecedented rise in temperatures [C6] as can be seen on these graphs http://whyfiles.org/218glo_warm/images/v... and http://www.globalwarmingart.com/images/c...

There is much controversy and debate surrounding mankind’s contribution to global warming and climate change. The IPCC [D4] has conducted the most detailed examination of climate change to date and concludes that human cause is ‘very likely’ (more than 90%) [C7] [M4].



3 - AN UNPRECEDENTED RISE IN TEMPERATURE
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EXPECTED RISE IN TEMPERATURES
During Earth’s current warming phase we’ve seen temperatures steadily rise by 9°C over the last 18,000 years [C3], a rise of one two thousandth of a degree Celsius per year (0.0005°C), this can be considered to be the natural rate at which the earth is warming.

THE 100 YEARS FROM 1905 TO 2005
In 1905 the average global temperature was 13.71°C, in 2005 it was 14.53°C [C8] [S3]
Expected natural increase 0.05°C
Actual increase 0.82°C
Average annual increase of 0.0082°C
Warming 16 times faster than expected

THE 50 YEARS FROM 1955 TO 2005
In 1955 the average global temperature was 13.98°C, in 2005 it was 14.53°C [C8] [S3]
Expected natural increase 0.025°C
Actual increase 0.55°C
Average annual increase of 0.011°C
Warming 22 times faster than expected

THE 25 YEARS FROM 1980 TO 2005
In 1980 the average global temperature was 14.14°C, in 2005 it was 14.53°C [C8] [S3]
Expected natural increase 0.0125°C
Actual increase 0.39°C
Average annual increase of 0.0195°C
Warming 39 times faster than expected



4 – THE CAUSES OF GLOBAL WARMING
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Global warming is the result of two contributory factors – the greenhouse effect and solar variation. Both are natural occurrences and cause Earth’s temperature to warm and cool. Since the Industrial Revolution [S4] the emissions of greenhouse gases has risen dramatically [C9] and there has been a corresponding rise in global temperatures [C10].


4A - GREENHOUSE EFFECT
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WHAT IS THE GREENHOUSE EFFECT?
The atmosphere acts like a blanket trapping heat and keeping Earth at a habitable temperature, it’s this retaining of heat that is referred to as the Greenhouse Effect [M5]. The greenhouse effect is caused by greenhouse gases [M2] that trap heat from the sun, the more greenhouse gases there are the more heat is retained.


GREENHOUSE GASES - NATURAL
The primary natural greenhouse gases are water vapour (H20), carbon dioxide (C02), methane (CH4), nitrous oxide (NO) and tetraflouromethane (CF4) [C1].

Water vapour is the largest component greenhouse gas and is almost entirely natural [S1] but it’s not very good at retaining heat. Most greenhouse gas is naturally occurring. Without any greenhouses gases our atmosphere would retain considerably less heat and Earth would be some 30°C colder [C2].

As with temperatures, there is a natural cycle in the amount of CO2 in the atmosphere. Ice core samples extending back some 650,000 years [C12] show the minimum amount of atmospheric CO2 to have been around 190 ppmv [D2] and the maximum about 300 ppmv [C13]. The worry is that the current levels of CO2 are considerably higher at around 385 ppmv [C9]


GREENHOUSE GASES - ANTHROPOGENIC
The manmade greenhouse gases include the naturally occurring ones as well as synthetic gases consisting of carbon and halogens [D1]. The group of gases called chlorofluorocarbons (CFC’s) are perhaps the best known of these. Many of the manmade greenhouse gases are also responsible for ozone depletion [M3].


CHANGING LEVELS OF GREENHOUSE GASES
Excluding water vapour, the most influential greenhouse gases are carbon dioxide and methane, respectively these account for 99% and 0.5% of greenhouse gases [C11]. Since the start of the Industrial Revolution there has been a 31% increase in the amount of CO2 in the atmosphere and a 150% increase in the amount of methane [C14]. Although methane occurs in much smaller quantities it is far more effective at retaining heat and is responsible for between 4 and 9% of the greenhouse effect, CO2 is responsible for between 9 and 26% [C15].

The year on year trend is an increasing amount of CO2 deposited in the atmosphere from virtually nil 150 years ago to 2 billion tons a year 50 years ago to today’s level of around 7 billion tons a year [C12]. The current level of CO2 in the atmosphere is around 385 ppmv and increasing [C9], this is the highest it’s been since the Cenozoic era some 60 million years ago [C17].

As the amount of greenhouse gas increases so does the temperature, the link between the two is a direct correlation [C18].


GREENHOUSE GASES - SOURCES
Three quarters of the greenhouse gas emissions for which humans are responsible result from the burning of fossil fuels (coal, oil and gas) and much of the remainder results from farming and agricultural activities.

The largest contributors of all greenhouse gases are power generation (21.3%), manufacturing and other industrial processed (16.8%), fuel for transportation (14.0%), farming and agriculture (12.5%), extraction and processing of fossil fuels (11.3%), domestic and commercial use (10.3%), land use, deforestation and other biomass burning (10%) [C19].

Carbon dioxide accounts for 72% of all man-made greenhouse gases, methane 18% and nitrous oxide 9% - a total of 99% between them. Power generation and industry contribute just over half the total carbon dioxide emissions whereas farming and agriculture are the primary producers of methane (46.6%) and nitrous oxide (88.0%) [C19].

Fossil fuels are hydrocarbons meaning they’re made up of carbon and hydrogen. When they’re burned they react with the oxygen in the air and the primary byproducts are water and carbon dioxide. These fuels are used in power generation, to heat homes and offices, to power factories, to drive our vehicles and many more uses.

Other manmade causes of greenhouse gases include deforestation [S5], fertilisers, air conditioning units, fridges and freezers, numerous industrial and chemical processes, fire suppressants, coal mining, effluent, landfill sites, livestock and rice cultivation [C20].

There are natural causes of greenhouse gases including volcanic activity, the seas and oceans, natural decay of plants and animals and the natural melting of ice caps.


4B – SOLAR VARIATION
Solar variations are changes in the amount of heat energy emitted from the sun and there are many reasons for this. The primary variation is caused by solar cycles, a pattern that repeats itself at 11 year intervals. However, the difference between the highest and lowest output is tiny, about 0.1% [C22] but it is enough to contribute to the warming of the planet. There are many other cycles that the sun goes through ranging from 22 years to several thousand years [C22]; there may be longer ones that haven’t yet been detected.

The heat energy received from the sun is 1366 W/m² (Watts per square metre) and it’s estimated that since 1750 this has increased by 0.3 W/m² whilst during the same time, anthropogenic global warming has contributed a further 2.4 W/m² [C23].

In the short term at least, solar variation has little effect on global warming and climate change. Over many thousands and millions of years the changes are significant and together with other astronomical factors [S6] can explain global warming and cooling cycles over periods of thousands of years.


4C – FEEDBACK OR COMPOUND PROCESS
Global warming is a self-perpetuating cycle. If we take melting ice as an example, as the ice melts it releases greenhouse gases from within the ice and trapped underneath the ice; the melting of Siberian permafrost is a good example of this [C21]. Further, as the ice melts it exposes the land beneath and forms melt-water lakes, both of which absorb more solar heat radiation than the ice did. The result of which is that the earth warms further causing more ice to melt and so the cycle continues.