MYTH: THE EARTH ISN'T REALLY WARMING

Myth #1: There is no evidence that the earth is getting warmer.

There exists ample evidence that global warming is real and occurring now. In fact, scientists around the world agree that global warming is happening and happening far more quickly than originally predicted.

Following are the key changes currently being observed:

Climatic changes

• Increase in global average surface temperature of about 1°F in the 20th century

• Decrease in snow cover and sea ice extent and the retreat of mountain glaciers in the latter half of the 20th century

• Rise in global average sea level and the increase in ocean water temperatures

• Increase in average precipitation over the middle and high latitudes of the Northern Hemisphere, and over tropical land areas

• Increase in the frequency of extreme precipitation events in some regions of the world

• Thawing of permafrost

Ecological changes

• Lengthening of the growing season in middle and high latitudes

• Pole ward and upward shift of plant and animal ranges

• Decline of some plant and animal species

• Earlier flowering of trees

• Earlier emergence of insects

Source: Union for Concerned Scientists / Gristmill

Myth #2: There is no consensus among scientists.

There is an overwhelming consensus among climate, ocean and atmospheric scientists that the global climate is rapidly warming and that an increase in human CO2 emissions is the primary cause.

The most respected source of scientific (peer-reviewed) information is the Intergovernmental Panel on Climate Change (IPCC). Consisting of more than 1,250 authors and 2,500 scientific experts from over 130 countries, the panel was organized by the United Nations Environment Program and the World Meteorological Organization in 1988 to examine scientific information on global warming and climate change. The panel's most recent report, Climate Change 2007: The Fourth Assessment Report, is the most comprehensive and up-to-date evaluation of global warming and serves as the basis for most international climate negotiations. The report examines all published and peer-reviewed scientific information produced over the last few years to assess what is known about the global climate, why and how it occurs, its impact on humans and the environment. The full report will be released in November 2007.
For more information: http://www.ipcc.ch/

Additional links to organizations that recognize Global Warming:

NASA's Goddard Institute of Space Studies (GISS)
http://www.giss.nasa.gov/edu/gwdebate/
National Oceanic and Atmospheric Administration (NOAA)
http://www.ncdc.noaa.gov/oa/climate/globalwarming.html
Intergovernmental Panel on Climate Change (IPCC)
http://www.grida.no/climate/ipcc_tar/wg1/index.htm
National Academy of Sciences (NAS)
http://books.nap.edu/collections/global_warming/index.html
State of the Canadian Cryosphere (SOCC)
http://www.socc.ca/permafrost/permafrost_future_e.cfm
Environmental Protection Agency (EPA)
http://yosemite.epa.gov/OAR/globalwarming.nsf/content/index.html
The Royal Society of the UK (RS)
http://www.royalsoc.ac.uk/page.asp?id=3135
American Geophysical Union (AGU)
http://www.ametsoc.org/policy/climatechangeresearch_2003.html
American Institute of Physics
http://www.aip.org/gov/policy12.html
National Center for Atmospheric Research (NCAR)
http://eo.ucar.edu/basics/cc_1.html
American Meteorological Society (AMS)
http://www.ametsoc.org/policy/jointacademies.html
Canadian Meteorological and Oceanographic Society (CMOS)
http://www.cmos.ca/climatechangepole.html

Source: Gristmill / Real Climate / Inconvenient Truth

Myth #3: The Urban Heat Island effect is mistaken for global warming.

Warming is observed everywhere, not just in cities. Often those who refute the reality of global warming will argue that scientists are really observing “urban heat island effect”—that cities tend to trap heat due to the abundance of buildings and asphalt. While cities do trap heat, warming is observed everywhere, not just in cities. Long-term temperature records showing only rural areas are nearly identical to long-term records including both rural areas and cities. Additionally, since cities represent a tiny fraction of the surface area of the earth, “urban heat islands” have a negligible effect on then overall warming of the planet.

Source: An Inconvenient Truth

Myth #4: Antarctic ice sheets are growing.

It is unclear whether the total mass balance of Antarctic ice is shrinking or growing. The mass balance of Antarctica’s ice sheets represents a complex balance between snowfall, ice melting, and ice flow. While most of Antarctica remains cold enough that melting is not yet an issue, and snowfall is actually increasing, global warming accelerates the flow of ice into the sea. While some ice sheets are growing, warming is also causing Antarctic ice sheets to shrink as more ice flows out to the sea. Moreover, localized impacts of climate change simply do not outweigh global trends that scientists are closely observing. Parts of Antarctica have warmed as much as 4.5 degrees Fahrenheit in the last 50 years, the most rapid rise anywhere in the world. With rising temperatures has come the collapse of massive ice shelves, some of which had been stable for over 20,000 years! In the last three years two massive, Rhode Island-sized pieces of ice have collapsed, and warming temperatures threaten much of the remaining Larsen Ice Shelf.

Source: An Inconvenient Truth, Shepherd and Wingham 2007, IPCC.

Myth #5: Many glaciers are not melting.

An estimated 85% of the earth’s glaciers are shrinking. For example, some people claim that Greenland’s ice is growing (Michael Crichton’s novel State of Fear for instance), a common misconception. However, recent satellite data from NASA shows that Greenland’s icecap is shrinking every year, causing sea levels to rise. The loss of that ice doubled from 1996 to 2005—a loss of 50 cubic kilometers of ice in 2005 alone!

According to the Glacial Balance report, from the State of the Cryosphere division of the National Snow and Ice Data Center, there is an overall accelerating rate of glacial mass loss. The World Glacier Monitoring Service states similar findings, the most recent data coming from 2004. While “some” glaciers are certainly growing, studies such as these are designed to determine a global trend by carefully assessing glaciers from all regions of the globe.

Furthermore, photographic images of before and after clearly illustrate the visible effects of these findings, as do the compelling animations of recent changes in Glacier Bay National Park.

Case Study: Glacier National Park is a Global Warming Laboratory…

The glaciers of Glacier National Park, like glaciers around the world, are shrinking as warming temperatures are melting them away. The day-by-day changes are not dramatic, however, observed over decades, the transformation is astounding. If nothing is done to curb global warming, Park scientists predict that as early as 2030 there may not be a single glacier left in Glacier National Park.

We can’t ignore the facts:

• Some of the Park's best known glaciers have already shrunk by more than half. For example, Boulder Glacier’s drastic decline was featured in the film An Inconvenient Truth.

• The number of glaciers in the park has dropped from an estimated 150 in 1850 to around 35 today.

• Since 1968, some of the smaller glaciers have disappeared entirely.

The impact of rising temperatures will not only translate into less ice. Retreating glaciers have a devastating impact on natural ecosystems that have taken thousands of years to develop. Sadly, the natural treasures the park was created to protect may disappear along with the ice.

Sources: Gristmill / Sierra Club

MYTH: HUMANS ARE NOT CAUSING GLOBAL WARMING

Myth #6. Humans are not responsible for global warming.

The evidence overwhelmingly points to humans as the cause of global warming. In its 2001 report, the Intergovernmental Panel on Climate Change stated, "There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities." Now the language is even stronger. In the latest (2007) IPCC report, with inputs from many thousands of measurement databases, the organization states with “very high (more than 90%) confidence that the globally averaged net effect of human activities since 1750 has been one of warming”. This warming is attributed to human activities which lead to emissions of greenhouse gases, including carbon dioxide, methane, and nitrous oxide.

Climate models developed by groups of scientists around the world agree that the temperature over all the continents has already warmed significantly more than can be explained by natural sources of climate variability (including volcanoes and solar intensity variations). (IPCC 2007)

Sources: IPCC 2001, IPCC 2007.

Myth #7. Global warming is part of the earth’s natural cycle of warming and cooling.

Global warming at this rate is almost certainly not natural. Climate does oscillate naturally over time, and from studying tree rings, lake sediment, ice cores, and other natural features that provide a record of past climates, scientists know that changes in climate, including abrupt changes, have occurred throughout history. Abrupt changes of the past occurred only when North America had an enormous ice sheet, either during the ice age or while the Earth was warming out of the ice age. Ice cores taken from Antarctica show that carbon dioxide levels are higher now than they have been at any time in the last 650,000 years, which means we are outside the normal realm of variation. More CO2 in the atmosphere means more warming.

Source: Inconvenient Truth

Myth #8. The medieval warming period was as warm as it is today.

There was in fact a medieval warm period, but it was not as warm as now. This myth persists from the early days of paleoclimatology, however it is not supported by reconstructed temperature records. Current estimates of the last thousand years of northern hemisphere temperatures suggest that at no prolonged time during this period were temperatures as warm as at present. Source: Mann et al. 1999.

Myth #9. There are many different causes of global warming. Why worry about CO2?

CO2 is major component of human-caused climate change. Climate is sensitive to many things besides carbon dioxide – sunspots, for one, as well as water vapor. But that doesn't mean we shouldn't worry about CO2 and other human-influenced greenhouse gases. The fact that the climate system has been shown to be sensitive to many sorts of natural changes throughout history should serve as a red flag: We need to pay attention to the massive and unprecedented changes we are causing.

Source: Inconvenient Truth

Myth #10: The sun is the source of warmth, so global warming is likely due to changes in solar radiation.

Recent changes in solar intensity can not explain the warming climate. Studies at the Max Planck Institute for Solar System Research show that solar activity affects the climate, but plays only a minor role in the current global warming.

Since the middle of the last century, the sun has been very active, as indicated by frequent occurrences of sunspots, gas eruptions, and radiation storms, and the changes in the solar activity look similar to the changes in the mean temperature of the earth. However, researchers at the Max Planck Institute have shown that the sun can be responsible for, at most, only a small part of the warming over the last 20-30 years. They took the measured and calculated variations in the solar brightness over the last 150 years and compared them to the temperature of the earth. Although the changes in the two values tend to follow each other for roughly the first 120 years, the Earth’s temperature has risen dramatically in the last 30 years while the solar brightness has not appreciably increased in this time.

Source: Krivova and Solanki 2004.

Sources: USGS, Oak Ridge National Laboratory.

Myth #12: The hole in the ozone causes global warming.

There is only a minor relationship between climate change and the ozone hole. The hole in the ozone layer–-a part of the upper atmosphere that contains high concentrations of ozone gas and shields the planet from the sun’s UV radiation–-is due to man-made chemicals called CFCs which were banned by an international agreement called the Montreal Protocol. The primary effect of the ozone hole is that it allows extra UV radiation to reach the earth’s surface. Both CFCs and ozone are greenhouse gases, so their concentrations affect global warming, but neither are among the strongest forcings for climate change.

Source: Real Climate

MYTH: SCIENTISTS CAN'T PREDICT FUTURE WARMING

Myth #13. Global cooling was predicted in the 1970s.

Global cooling was not predicted in the scientific literature. The perception that global cooling and an imminent ice age were predicted in the 1970's has much to do with the popular press, both then and now, and little to do with peer-reviewed science. In reality, scientists of the 1970's were seeing a short reversal (from the 40s to 70s) of the measured warming trend, and concluding correctly that not enough was known at the time to make predictions of the future climate. A fine discussion of the fact and fiction of this topic can be found at: http://www.realclimate.org/index.php/archives/2005/01/the-global-cooling-myth

And a compendium of articles from the time can be found at: http://www.wmconnolley.org.uk/sci/iceage/

This is in stark contrast to the predictions of warming being made now in peer-reviewed publications.

Source: Real Climate

Myth #14. Climate models can’t predict the climate many years in advance.

Climate models are specifically designed to operate into the distant future (and past). Much of the confidence in current climate predictions comes from looking at ensembles of model simulations – this involves asking the same question of many models using many initial conditions. When one sees a consistent picture across a broad sweep of contributing models, one can have higher confidence in the results.

Part of the confusion over how much to trust computer simulations of future climate comes from our experience with weather predictions. The climate of a place is often described as 'the average weather', and climate predictions try to anticipate changes in this average. As such, they're quite different than weather forecasts. We find the following discussion from Grist.org to be helpful:

Think of it as the difference between trying to predict the height of the fifth wave from now versus predicting the height of tomorrow's high tide. The former is a challenge -- to which your salty, wet sneakers will bear witness -- but the latter is routine and reliable. This is not to say it's easy to predict climate changes. But seizing on meteorologists' failures in order to cast doubt on a climate model's 100-year projection is an argument of ignorance. (See http://gristmill.grist.org/story/2006/11/19/221636/43 for more.)

Source: Grist.org

Myth #15. Scientists are just exaggerating in order to get funding.

There are better ways to get money than publishing honest science on global warming. One way is becoming an industry-sponsored global warming skeptic. It's interesting to note that the authors on sites such as www.realclimate.org volunteer their time, whereas well-known skeptics like the University of Virginia's Pat Michaels receive money directly from the energy industry to spread their views. You can read interesting articles on the subject from the Seattle Times (http://seattletimes.nwsource.com/html/nationworld/2002549346_globewarm11.html) or Wired Magazine (http://www.wired.com/techbiz/media/news/2006/07/71486).

Sources: Real Climate, The Seattle Times, Wired.

MYTH: THERE'S NOTHING I CAN/SHOULD DO

Myth #16. Warmer weather is a good thing. And what do a few degrees really matter?

For most people, the status quo is a good thing. Economies around the world have developed to take advantage of the types of weather that occur in different places. As the climate changes, we'll have to pour billions of dollars into switching our economies over to activities that make sense in the new climate.

In addition, the temperature increases from global warming will not be evenly distributed -- some areas won't get warmer at all, while others will see large changes. A mere 2 degree rise in the earth's mean temperature won't be much consolation to you if the area where you live goes up by 15 degrees. Also, there are parts of the world where a small temperature rise can make a really big difference. For instance, big portions of the world's population (like the western USA or northern India) rely on winter snowfall to provide summer water supplies. A small difference in temperature can mean a big difference in how much snow collects during the winter. This can lead to wintertime floods and summertime droughts.

Myth #17. No problem! More plants will grow, hence removing more C02 and increasing food supplies.

Not nearly enough plants will grow to offset the increasing CO2 levels. The problem is largely that carbon dioxide is not the only limiting factor in plant growth. For instance, plants may show an initial growth spurt only to be slowed by availability of nitrogen or phosphorous in the soil. Besides, even trees eventually decompose and release their stored carbon back to the atmosphere in the form of CO2. The plant response has been studied directly by researchers at Duke University and the Swedish University of Agricultural Sciences, among others. A nice review paper is available at http://face.env.duke.edu/PDF/np173-07.pdf.

Sources: Hyvönen et al, 2007.

Myth #18. Societies can easily adapt to global warming later.

Putting it off will only make it harder. In recognition of this, 189 countries (including the US!) around the world have joined an international treaty, the United Nations Framework Convention on Climate Change (UNFCCC), that sets general goals and rules for confronting climate change. To quote from their web site, “It is hard to get the nations of the world to agree on anything, let alone a common approach to a difficulty which is complicated, whose consequences aren't entirely clear, and which will have its most severe effects decades and even centuries in the future.”

In addition to the difficulty of motivating people on a grand scale, some studies have suggested that we don't have a lot of time to get going before we commit ourselves to rather extreme impacts over the course of this century.

Myth #19. There is nothing I can do about global warming. It is too late.

There is a lot you can do, both personally and politically. Although most global warming emissions remain in the atmosphere for decades or centuries, the energy choices we make today can still greatly influence the climate our children and grandchildren inherit. We have the technology to increase energy efficiency, significantly reduce these emissions from our energy and land use, and secure a high quality of life for future generations. We have a small window of time and we must act now to avoid dangerous consequences.

Take Action Today!

BIBLIOGRAPHY:

Hyvönen R, Ågren GI, Linder S, Persson T, Cotrufo MF, Ekblad A, Freeman M, Grelle A, Janssens IA, Jarvis PG, Kellomäki S, Lindroth A, Loustau D, Lundmark T, Norby RJ, Oren R, Pilegaard K, Ryan MG, Sigurdsson BD, Strömgren M, van Oijen M and G Wallin. 2007. The likely impact of elevated [CO2], nitrogen deposition, increased temperature and management on carbon sequestration in temperate and boreal forest ecosystems: a literature review. New Phytologist 173:463-480.

Intergovernmental Panel on Climate Change, 2001 Climate change 2001: The scientific basis. Cambridge, UK: Cambridge University Press.

Krivova, N., and S. Solanki, 2004: Solar Variability and Global Warming: A Statistical Comparison Since 1850, Adv. Space Res. 34, 361-364 (2004)

Mann, M., R. Bradley, and M. Hughes, 1999: Northern Hemisphere Temperatures During the Past Millennium: Inferences, Uncertainties, and Limitations. Geophysical Research Letters, Vol. 26, No. 6, p.759.

Shepherd, A. and D. Wingham, 2007: Recent Sea-Level Contributions of the Antarctic and Greenland Ice Sheets, Science, Vol. 315. no. 5818, pp. 1529 – 1532.