Global Warming Myths

Because global warming is such a politically controversial issue, there are many myths about the subject.  Some of these myths are based upon a nugget of truth, and others are complete fabrications.  It's time to get them debunked. 

Myth #1:  'They' predicted an ice age in the 1970s

This myth is based upon stories in TIME and Newsweek in the 1970s regarding global cooling.  It was even quoted by Republican Sen. James Inhofe, chair of the Environment and Public Works Committee, on the floor on the Senate. This myth appeals to some people because the predictions have turned out to be so wrong. If 'they' were wrong in the 1970s on predicting global cooling, then 'they' could easily be just as wrong on recent global warming.  Deniers therefore conclude that the science of global warming remains unsettled.

A better conclusion, however, would be that one should not rely on the mass media for your science if you can find better sources.
 

Recent studies of the scientific literature at the time have concluded that the supposed "global cooling" consensus among scientists during the 1970s is indeed a myth.

"Thomas Peterson of the National Climatic Data Center surveyed dozens of peer-reviewed scientific articles from 1965 to 1979 and found that only seven supported global cooling, while 44 predicted warming. Peterson says 20 others were neutral in their assessments of climate trends."

Among those scientists who predicted continued global cooling, some based their conclusions on the assumption that human aerosol emissions would continue to increase rapidly.  Up until 1970, aerosol emissions (primarily sulfur dioxide) were increasing rapidly.  Aerosols block sunlight, causing global dimming and thus global cooling, and were primarily responsible for the very slight global cooling from 1940-1970.

Some scientists were concerned that if these emissions continued to accelerate, they would overwhelm the warming associated with carbon dioxide emissions and continue to cool the planet.  However, many countries began to pass Clean Air Acts in response to the various problems associated with these emissions (acid rain, for example), and worldwide sulfur dioxide emissions have actually decreased since 1980.  In short, the scenario which was predicted as the possible cause of global cooling did not come to pass.

The lesson to be learned from this myth is that it's important to get our scientific information directly from scientists, rather than filtered through the media.  Media bias is one of the most common causes of misinformation with regards to global warming even today.  Some articles are too sensationalist, and others provide misinformation stemming from a political agenda.  This is why the Intergovernmental Panel on Climate Change (IPCC) is such a critical organization, and why it won a Nobel Prize.

Myth #2:  There is no scientific consensus on man-made global warming

This myth often stems from a misunderstanding of the term 'consensus'.  In this context, 'consensus' does not mean 'unanimity'.  The term generally means 'majority', but in the context of man-made global warming, it means 'vast majority' of agreement among scientists.

A nice compilation of the various groups which are in agreement about man-made global warming is available at Logicalscience.com.  Every so often, certain parties will attempt to compile lists of scientists who disagree with some aspect of the theory in an attempt to disprove the consensus.  The two most oft-cited lists are the Oregon Petition and Senator James Inhofe's list of 400.

In both cases, the lists were not limited to people with expertise in climate science, but essentially allowed anybody with any college degree (in the case of the Oregon Petition) or any scientific degree (in the case of Inhofe's list) to sign.  In the example of Inhofe's list, it included botanists, chemists, mathematicians, economists, and political scientists, to name a few.

When considering how many scientists work in these fields, 400 is a fraction of a percent and certainly does not disprove a scientific consensus on the subject.  Particularly since many on the list have no expertise or experience in climate science research.  The Oregon Petition has been found to be fraudulent, and a new version was recently circulated.

In short, it is quite apparent that there is indeed a scientific consensus on man-made global warming.  A nice description of what the consensus is can be found at RealClimate.

Myth #3:  One volcanic eruption emits more CO2 than humans have in [insert length of time here]

Because volcanic eruptions look so massive, some people assume they emit vast amounts of carbon dioxide.  However, studies have shown that on average, annual human CO2 emissions are at least 100 times greater than volcanic CO2 emissions.  This particular myth has no basis in reality.  It's simply completely wrong.

Myth #4:  Mars and/or all the planets in our solar system are warming, so the Sun is causing global warming

There is a nugget of truth to this myth.  Our observations of Mars appear to indicate that the planet is warming.  However, we don't have a lot of data regarding the climate of Mars, and while some regions of the planet are warming, we aren't certain that the planet is warming as a whole.  If Mars is experiencing global warming, scientists believe it's due to dust storms darkening its surface, causing the planet to absorb more sunlight (a.k.a. decreased albedo).

A sub-myth is that both ice caps on Mars are melting.  In reality, while the southern polar cap is vaporizing, the northern cap is expanding.

A few other planets in our solar system appear to be warming.  For example, Pluto appears to be warming at a rate much faster than Earth (the opposite of what you would expect from a planet further from the Sun if the warming were due to solar effects), most likely because of its orbital cycles (seasonal changes).  However, of the many planets and moons in our solar system, the vast majority appear to be experiencing no significant temperature change.

Moreover, we don't need to look at other planets to measure changes in the Sun - we have satellites which have directly measured solar output for the past 30 years.  The satellite data shows that solar irradiance has not changed on average over that period, so it cannot be causing global warming on Earth or any other planet.

Myth #5:  Because the Earth's climate has changed naturally in the past, the current warming is natural

In order to know if the current climate change is the same as past climate changes, one must understand what caused the climate to change in the past.  This is discussed in the global warming and climate change causes wiki, which shows that the current warming cannot be explained by the effects which caused past natural climate changes.

Myth #6:  Global warming is just a massive hoax

This myth ignores the vast amount of scientific evidence supporting man-made global warming.  However, even ignoring the evidence, this myth is simply not possible.  As discussed in Myth #1, scientists have been predicting global warming since the late 1960s.  Thus perpetrating such a hoax would require millions of scientists all colluding over 4 decades, falsifying data with not one single credible person revealing the supposed hoax.  Most importantly, credible skeptical scientists like Richard Lindzen might disagree with the theory or its projections, but they don't argue that it's all a fraud.

Furthermore, ignoring the massive amount of collusion that such an immense hoax would require, and the fact that scientific frauds on far, far smaller scales have been revealed almost immediately, consider the fame that a scientist would get for disproving this hoax.  If global warming were really due to the Sun, and all scientists have been saying it's not, and another scientist proved that this was the case - you're talking infamy, Nobel Prizes, etc. etc. Any scientist would love to disprove man-made global warming if it were wrong.

In short, it's simply impossible for man-made global warming to be a hoax.  This particular conspiracy theory has no basis in reality.

Myth #7:  Natural sources emit so much more CO2 than humans that we can't be causing global warming

One often hears the skeptics say that mankind is only producing about 5% of greenhouse gas emissions. Why that is not much at all, is it? This number is oft-quoted but it is very disingenuous. Out of all of the CO2 emitted from both natural and anthropogenic (man made) sources, it is true that only about 5% of the total, per year, is from those human activities.

However, this argument ignores ninth grade Earth Science class. The carbon cycle is central to our understanding of this issue.

Carbon dioxide is produced naturally here on Earth, by such means as animal respiration (or digestion, in the case of methane) and the decay of plant and animal matter. This carbon is then naturally removed or “recycled” from the atmosphere, mostly through the process of photosynthesis, or plant respiration.

For more then 10,000 years, since the end of the last ice age (yes! Planet Earth has had climate changes in the past, though not all of these changes have had the same cause) the carbon cycle has been relatively stable. The amount of carbon dioxide that entered the atmosphere was roughly equal to the amount of carbon dioxide that was removed and the overall atmospheric CO2 concentration remained constant, at about 280ppm.

Climate change is about change. Humans have upset the natural budget of the carbon cycle. We have accomplished this through certain activities such as energy production (burning fossil fuels release large quantities of CO2 into the atmosphere) and deforestation. Humans are only adding carbon to the atmosphere, which is just half of the equation; mankind is not removing any carbon dioxide from the atmosphere. In addition, deforestation reduces the amount of CO2 that nature is able to remove from the atmosphere.

The next time someone argues that humans are only responsible for 5% of the atmospheric CO2, please mention the carbon cycle. They probably just forgot. Forgetting could be dangerous if they are talking about issues that are important. Suppose that I was budgeting to save money for something real nice. Suppose that I also only added up my incomes, but “forgot” to subtract my expenditures. I would have a pretty misleading amount in my bank account by the end of the year, right?

The atmospheric CO2 concentration has increased by about 37% since pre-industrialization times, and is now over 380 ppm.

A sub-myth is that if human CO2 emissions are causing global warming, we should just stop breathing, since we emit CO2 when we exhale.  The CO2 we breathe is part of the natural carbon cycle.  When we exhale, we're not adding any new carbon to the system - we're just circulating carbon that was already there.

Breathe easy - you're not contributing to global warming by doing so!

Myth #8:  CO2 is such a small fraction of the atmosphere, there's no way it's causing global warming

It's true that carbon dioxide currently accounts for just 384 parts per million (ppm) of the gases in our atmosphere.  That's 0.0384%.  Seems tiny, right?

The problem with this myth is that the concentration of CO2 isn't enough information to tell you how much global warming it's causing.  For example, arsenic is lethal at 15-30 ppm.  In this case you need to know the toxicity in addition to the concentration to know if the amount of arsenic is dangerous.  In the case of a greenhouse gas, you need to know its global warming potential.

The bottom line is that while 384 ppm or 0.0384% might sound small, that doesn't mean it's incapable of having a large effect.  In fact, nearly 99% of the Earth's atmosphere is composed of nitrogen and oxygen, which are not even greenhouse gases.

Myth #9:  Water vapor is a more important greenhouse gas than CO2

The nugget of truth to this myth is that water vapor comprises about 1% of the atmosphere (about 26 times more than CO2), and it accounts for the largest percentage of the greenhouse effect on Earth (approximately 36-66%).

However, the critical point is that water vapor cannot cause global warming.  This is because the amount of water vapor in the atmosphere depends entirely on the temperature of the atmosphere.  A warmer atmosphere will hold more water vapor.  So while water vapor can act as a feedback and amplify global warming, it cannot initiate global warming on its own.

Myth #10:  Global warming stopped in 1998

While it's true that in most surface temperature records 1998 remains the hottest year on record (NASA concluded that 2005 was slightly warmer), that doesn't mean that global warming has stopped.  The reason 1998 remains the hottest year on record is that it was an anomalously strong El Nino cycle year.

However, every year from 2001-2007 was hotter than every year in the 1990s other than 1998 (and every previous year on record).  Thus even though there has been no individual year hotter than 1998, the average global temperature has continued to increase, as is evident in this plot of the NASA global temperature data:

Myth #11:  Addressing global warming is too expensive to be worthwhile

One key point this myth misses is that global climate change threatens the very future of our species (and all others on the planet).  It's hard to imagine a dollar value worth more than the future of the human race.  Even disregarding this point, the costs of addressing global warming  have been greatly exaggerated by many.

One recent plan to address global warming would just cost less than 3% of the global gross domestic product (GDP) by 2030 to meet its lowest targets — or 0.12% annually.  The IPCC suggests similar annual mitigation costs of 0.2-3.5% of current world GDP.  That compares favorably to global economic growth that every year has averaged almost 3% since 2000.  The damage from unabated climate change, meanwhile, might eventually cost the global economy 5-20% of GDP each year, every year, according to a British government report last year.

An appropriate analogy is buying insurance.  A valuable object is usually worth insuring.  While this may cost a significant amount of money in the short-term, it ensures that if the object is damaged in the future, it will not be a catastrophic result.  The same is true of global warming - a significant but affordable short-term investment will help avoid potentially catastrophic damage in the long-run.

Myth #12:  A little warming is nothing to worry about a.k.a. Warmer is Better

A frequent argument is that life has flourished during the warmer periods on Earth, therefore warmer must be better.  An obvious logical flaw to this argument is that there is a point at which the planet becomes too warm.  After all, we can't live on the Sun!

In fact, we just have to look at recent local warming events to see that warmer is clearly not better.  For example, during the European heatwave of 2003, the temperature on the continent only averaged 2.3°C warmer than the 1961-1990 average.  Yet during this heatwave, 35,000 people were killed.  There was also huge economic damage due to fires and droughts.   Wildfires in Portugal alone caused 1 billion Euros of damage. France lost 20% of its grain harvests while wheat harvests in Ukraine and Moldova were down 75 and 80% from normal, respectively. Overall, wheat production in the European Union was down 7% from the previous 5-year average.  Studies have shown that the human contribution to this heat wave was significant, and this sort of heat wave will become commonplace as the planet warms.  In fact, we're currently on pace to reach an average global temperature of 2°C warmer by mid-century.

A sub-myth is that plants will benefit from increased CO2.  While it's true that generally speaking plants do grow better when exposed to larger amounts of CO2, the associated temperature increase and subsequent increase in droughts negatively impacts their growth (as illustrated in the 2003 European heatwave).

Measurements of CO2 absorption from forests have indicated that their carbon absorption is decreasing. Ground and satellite observations have seen an increased 'browning' of the forests as well.

Scientists theorize that we may be near a turning point where forests actually become net carbon sources rather than sinks.