A Reexamination of Climate Change Issues
Issues with Polar Bears and Global Warming
updated October 13, 2022
 This well-known image has often been portaited as polar bears being “stranded” on shrinking sea ice, but it is shown that polar bears are not actually in danger. |
Government reports over recent years have been claiming imminent extinction threats of polar bears due to the effects of global warming, and in January of 2008 those reports had been discredited as being unscientific in Congressional Hearings. Nonetheless, in May of 2008 the polar bears had been listed as a threatened species due to pressure from media and lobbying groups— which set a new precedent representing the first linkage of species endangerment to the effects of global warming. Polar bear populations actually have been increasing in the Arctic due to hunting restrictions which have been imposed years ago. This article contains a summary of issues concerning the effects of global warming on polar bear population sizes, and well as related political and media issues. |
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Summary and Overview
It is widely accepted that polar bear populations have risen worldwide to as many as 24,000 from a previous low of as little as 5,000 in the 1970s, due to new restrictions banning the practice of hunting polar bears from aircraft and ships, as well as other limits being imposed on hunting the bears and their prey.
Although claims exist of polar bear populations potentially being effected by retreating Arctic ice, it is difficult to isolate the degree of the effects of the retreating ice due to the fact that the bear populations have generally been increasing due to the hunting restrictions.
While Al Gore’s film “An Inconvenient Truth” claims that polar bears are drowning due to retreating Arctic ice, most scientists agree that those claims are false. Polar bears are very good swimmers and they can cross areas of water for distances of over 60 miles. However, in 2004 four corpses of drowned bears had been found a few kilometers from the edge of the ice by researchers, but it was shown that they died due to being caught in a strong Arctic storm while swimming.
One widely held view by scientists such as Canadian biologist Dr. Mitchell Taylor, who is the director of wildlife research with the Arctic government of Nanavut, is that recently retreating ice has not decreased polar bear populations at all, mainly due to the fact that decreased ice actually exposes more prey for the bears to eat. He points out that polar bear populations have been increasing overall and have also survived much more extreme climate temperature periods many times in the past.
Andrew Derocher of the World Conservation Union, who is a professor of biological sciences at the University of Alberta in Edmonton, has an opposing view that retreating ice will effect bear populations significantly through habitat loss. He claims that the regulations increasing limits on hunting of the polar bears and their prey have contributed to the rise in polar bear populations rather than more prey being exposed by retreating ice for the bears to eat.
Both scientists have been accused of having conflicts of interest, however. Critics of Taylor point out that his recent study was commissioned by the Intuit-dominated government of Nunavit, which has an agenda to encourage polar bear hunting in Intuit communities and the government also stands to gain revenue from the hunts. Also, scientists who find little evidence of detrimental effects of global warming such as Taylor are frequently accused of protecting the interests of oil companies looking to expand petroleum exploration into the Arctic.
On the other hand, critics of scientists who do claim evidence of global warming links such as Derocher point out that his findings are instrumental for passing global warming legislation which is associated with benefiting other energy industries as well as deceptive socio-political agendas that actually have little or nothing to do with the issue of global warming.
When U.S. Government reports started forecasting potential for polar bear extinctions in the coming century due to global warming, a frenzy of media reports ensured the polar bears becoming a symbol of the global warming movement, and many mainstream environmental organizations set precedents for their members to exploit the polar bear issues.
Then in January 2008, forecasting expert Professor Scott Armstrong of the University of Pennsylvania gave Congressional testimony showing how U.S. Government studies projecting future declining polar bear populations due to Arctic ice growth are seriously flawed through their reliance on complex sets of assumptions, and they should not be considered to be scientific forecasts.
Despite the fact that polar bear populations are currently thriving overall and the proof of scientific flaws in studies forecasting future declining polar bear populations, Secretary of the Interior Dirk Kempthorne announced on May 14, 2008 that he is accepting the recommendation of U.S. Fish and Wildlife Service Director Dale Hall to list the polar bear as a threatened species under the Endangered Species Act (ESA), claiming that the listing is based on the “best available science,” which shows that loss of sea ice threatens and will likely continue to threaten polar bear habitat. Listing the polar bear as a threatened species has significant public policy consequences. It sets a new precedent representing the first linkage to species endangerment with global warming.
A June 2008 report by the International Energy Agency says the world must undergo a “new global energy revolution” to halve carbon dioxide emissions by 2050, with the bill for the agenda costing as much as $45 Trillion.
The Issue of the “Stranded Polar Bear Image”
View an Australian news broadcast reporting about the issue of a well-known photograph of polar bears appearing to be stranded on an ice floe in the Arctic actually originating from a photograph taken in the middle of the summer when the ice always breaks up. Also mentioned is the fact that bears are very good swimmers.
Following is a transcript from the three minute Australian news broadcast:
This well known picture has frequently been used as evidence to show the effects of global warming and its effects on the polar bear populations. It has been reprinted by many mainstream newspapers and used by Al Gore in slide presentations. But the photo wasn't current--it was 2 1/2 years old and it wasn't snapped by Canadian environmentalists, it was taken by Austrian marine biology student Amanda Bryd on a summertime field trip in August, when every year the ice breaks up regardless of the wider effects of global warming.
Bryd (when talking about the polar bears): "They did not appear to be in danger.. I did not see the bears get on the ice, and I did not see them get off.. I cannot say either way if they were stranded or not."
Dennis Semard of Environment Canada, who told Canada's National Post: "You have to keep in mind that the bears are not in danger at all. This is the perfect picture for climate change. You have the impression they are in the middle of the ocean and they are going to die. But they are not that far from the coast, and it was possible for them to swim, they are still alive and having fun."
Photographer Amanda Byrd gave her photo to fellow cruiser Dan Crosby to have a look. Byrd: "Dan Crosby gave the image to the Canadian Ice Service, who gave the image to Environment Canada, who distributed the image to seven media agencies, including AP."
Associated press released the photo 2 1/2 years after it was taken, on the day the United Nations released its major global warming report. That's where Sydney's Sunday Telegraph got the photo, running it from a story taken from the Daily Mail.
Amanda Byrd didn't think her photo necessarily described whether Global Warming is occuring. Byrd: "I take neither stand, I simply took the photos. If I released the image myself, it would have been as a striking image, nothing more."
However that is not how Al Gore saw it, he used it in a presentation on global warming: "Their habitat is melting, beautiful animals literally being forced off the planet... [Polar Bears] are in trouble, got nowhere else to go." Audience members reportedly let out gasps of sympathy.
View an Australian news broadcast reporting about the issue of a well-known photograph of polar bears appearing to be stranded on an ice floe in the Arctic actually originating from a photograph taken in the middle of the summer when the ice always breaks up. Also mentioned is the fact that bears are very good swimmers.
Following is a transcript from the three minute Australian news broadcast:
This well known picture has frequently been used as evidence to show the effects of global warming and its effects on the polar bear populations. It has been reprinted by many mainstream newspapers and used by Al Gore in slide presentations. But the photo wasn't current--it was 2 1/2 years old and it wasn't snapped by Canadian environmentalists, it was taken by Austrian marine biology student Amanda Bryd on a summertime field trip in August, when every year the ice breaks up regardless of the wider effects of global warming.
Bryd (when talking about the polar bears): "They did not appear to be in danger.. I did not see the bears get on the ice, and I did not see them get off.. I cannot say either way if they were stranded or not."
Dennis Semard of Environment Canada, who told Canada's National Post: "You have to keep in mind that the bears are not in danger at all. This is the perfect picture for climate change. You have the impression they are in the middle of the ocean and they are going to die. But they are not that far from the coast, and it was possible for them to swim, they are still alive and having fun."
Photographer Amanda Byrd gave her photo to fellow cruiser Dan Crosby to have a look. Byrd: "Dan Crosby gave the image to the Canadian Ice Service, who gave the image to Environment Canada, who distributed the image to seven media agencies, including AP."
Associated press released the photo 2 1/2 years after it was taken, on the day the United Nations released its major global warming report. That's where Sydney's Sunday Telegraph got the photo, running it from a story taken from the Daily Mail.
Amanda Byrd didn't think her photo necessarily described whether Global Warming is occuring. Byrd: "I take neither stand, I simply took the photos. If I released the image myself, it would have been as a striking image, nothing more."
However that is not how Al Gore saw it, he used it in a presentation on global warming: "Their habitat is melting, beautiful animals literally being forced off the planet... [Polar Bears] are in trouble, got nowhere else to go." Audience members reportedly let out gasps of sympathy.
Professor Scott Armstrong Exposing Inaccuracies in Polar Bear Studies
In January 2008, forecasting expert Professor Scott Armstrong of the University of Pennsylvania gave Congressional testimony showing how U.S. Government studies projecting future declining polar bear populations due to shrinkling Arctic ice are seriously flawed through their relying on complex sets of assumptions, and should not be considered to be scientific forecasts.
Scott Armstrong is the founder of the Journal of Forecasting and the International Journal of Forecasting, which are the two main journals that address the subject of forecasting. Armstrong is also a founder of the International Institute of Forecasters and of the International Symposium on Forecasting.
Mr Armstrong has published more than 50 peer-reviewed papers on forecasting. His first book on the subject, Long-Range Forecasting, was published in 1978 and revised in 1985. He is the editor of Principles of Forecasting: A Handbook for Researchers and Practitioners (2001) and the founder and co-director of the forecastingprinciples.com website. He has been working on forecasting problems for 48 years.
Transcript of Scott Armstrong’s Congressional Testimony
Following are portions of a transcript of Professor J. Scott Armstrong's testimony to the Senate Committe on Environment and Public Works, January 30, 2008. Armstrong explained how U.S. Government studies projecting future declining polar bear populations due to Arctic ice growth are seriously flawed by relying on complex sets of assumptions, and should not be considered to be scientific forecasts.
View a six minute video of Professor Armstrong's testimony
View the full transcript of Armstrong's testimony
...
My name is Scott Armstrong. I am a professor at the Wharton School of the University of Pennsylvania.
The decision on whether or not to list polar bears under the Endangered Species Act rests heavily on forecasting. I am addressing this Committee today as a forecasting expert.
I am a founder of the Journal of Forecasting and the International Journal of Forecasting, which are the two main journals that address the subject of forecasting. I am also a founder of the International Institute of Forecasters and of the International Symposium on Forecasting.
I have published more than 50 peer-reviewed papers on forecasting. My first book on the subject, Long-Range Forecasting, was published in 1978 and revised in 1985. I am the editor of Principles of Forecasting: A Handbook for Researchers and Practitioners (2001) and the founder and co-director of the forecastingprinciples.com website. I have been working on forecasting problems for 48 years.
...
Audit of Polar Bear forecasting
We conducted forecasting audits of two of the nine administrative reports that were prepared in 2007 to “...Support U.S. Fish and Wildlife Service Polar Bear Listing Decision.” We selected the reports Amstrup et al. and Hunter et al. as they appeared to be the primary forecasting documents.
Our concern was to establish whether the reports’ forecasts of the polar bear population over the balance of the 21st Century were the product of scientific procedures.
We found that the authors of both reports made complex sets of assumptions in order to derive their polar bear population forecasts. Critically, the authors assumed on the basis of general circulation model (GCM) forecasts that summer sea ice will diminish in the Arctic over the rest of the 21st Century. Green and Armstrong (2007) audited the procedures used by GCM climate modelers and found that their forecasts were not scientific. Forecasting sea ice conditions adds an additional level of complexity to the problem and the GCMs fail to reproduce actual sea ice conditions even when historical periods are simulated.
What if predictions about Arctic sea ice conditions over the 21st century turned out to be right? Would the polar bear forecasts then be useful? To assess this, each of the three authors of Armstrong, Green, and Soon (2008) used the forecasting audit software that is available on forecastingprinciples.com. ...
On average, the authors properly applied only 12% of relevant principles. In what occupations would work that follows 12% of proper procedures be considered acceptable?
...
Another example of what happens when principles are contravened
How did the authors of the Hunter et al. administrative report obtain forecasts of a rapidly diminishing polar bear population?
Consider again Exhibit 1. The labels that I will add show that these data represent the ice-free days in the Southern Beaufort Sea. None of the data shown in the exhibit were used by the authors to forecast the number of ice-free days over the 21st Century. Instead, they relied on a climate model (GCM) scenario of dramatically increasing numbers of ice-free days. This is in sharp contrast to what the data in the Exhibit seem to indicate.
Exhibit 3 shows the data with labels. It is reproduced from Figure 3 on page 26 of Regeher et al (2007), one of the nine USGS administrative reports.
Hunter and her colleagues then used only the five years of data indicated by the filled-in circles and polar bear population estimates for those years to conclude that there was a strong causal relationship between the number of ice-free days and the bear population growth rate.
Finally, they combined the GCM-originated ice-free-day scenario with their estimate of the effect of ice-free days (based on 5-years of data) in order to project the polar bear population over a period of nearly a century (Hunter, Figure 6). Their process ignored other influences on bear fertility and mortality.
Fully disclosed and peer reviewed
We have sought peer review from researchers and we are continuing to do so. The latest version of the working paper is always available at publicpolicyforecasting.com.
We sent our paper to all those whom we cited asking them if we had cited them correctly. This led to some changes and to a few suggestions on how to better describe what they had done.
Conclusions
To date, there are no scientific forecasts of the polar bear population over the 21st Century. Nor are there any forecasts to suggest that a decision to list them would produce benefits. I urge further study.
Forecasting Expert Scott Armstrong
In January 2008, forecasting expert Professor Scott Armstrong of the University of Pennsylvania gave Congressional testimony showing how U.S. Government studies projecting future declining polar bear populations due to shrinkling Arctic ice are seriously flawed through their relying on complex sets of assumptions, and should not be considered to be scientific forecasts.
Scott Armstrong is the founder of the Journal of Forecasting and the International Journal of Forecasting, which are the two main journals that address the subject of forecasting. Armstrong is also a founder of the International Institute of Forecasters and of the International Symposium on Forecasting.
Mr Armstrong has published more than 50 peer-reviewed papers on forecasting. His first book on the subject, Long-Range Forecasting, was published in 1978 and revised in 1985. He is the editor of Principles of Forecasting: A Handbook for Researchers and Practitioners (2001) and the founder and co-director of the forecastingprinciples.com website. He has been working on forecasting problems for 48 years.
TheClimateBet.com - “Polar bear fears groundless”
Following is an article on the website TheClimateBet.com explaining Professor Scott Armstrong's Congressional testimony regarding inaccurate means of forecasting being used in Government reports claiming reductions in polar bear populations.
https://www.theclimatebet.com/?s=polar++bear+fears+groundless
The U.S. government commissioned studies to support the listing of polar bears as a threatened or endangered species. Polar bear numbers are currently high and the population has been increasing rapidly in recent decades. Everyone likes polar bears, so this is good news. A decision to list would require forecasts that the current upward population trend will reverse. The government studies concluded that polar bear populations would decrease substantially.
Decision makers and the public should expect people who make forecasts to be familiar with the scientific principles of forecasting just as a patient expects his physician to be familiar with the procedures dictated by medical science. Three scientists, J. Scott Armstrong of the University of Pennsylvania, Kesten Green of Monash University, and Willie Soon of The Harvard-Smithsonian Center for Astrophysics, audited the government studies to assess whether they were consistent with forecasting principles. Their paper, “Polar Bear Population Forecasts: A Public-Policy Forecasting Audit,” has been accepted for publication in the management science journal Interfaces. It is the only peer-reviewed paper on polar bear population forecasting that has been accepted for publication in an academic journal.
They concluded that the government forecasts were based on false assumptions and their polar bear population forecasts contravened many principles for scientific forecasting. Indeed, the reports followed fewer than one-sixth of the relevant principles. Given the importance of the forecasts, all principles should be properly applied. In short, the government reports do not provide relevant information for this decision.
Research shows that for issues such as the population of polar bears—situations that are complex and where there is much uncertainty—the best forecast is that things will follow a “random walk;” in effect, this model states that the most recent value is the best forecast for all periods in the future. Because the polar bear population has been increasing over recent decades, however, a continuation of that trend over the short term is possible.
Copies of Armstrong, Green and Soon’s forthcoming paper are available at http://publicpolicyforecasting.com.
Following is an article on the website TheClimateBet.com explaining Professor Scott Armstrong's Congressional testimony regarding inaccurate means of forecasting being used in Government reports claiming reductions in polar bear populations.
https://www.theclimatebet.com/?s=polar++bear+fears+groundless
The U.S. government commissioned studies to support the listing of polar bears as a threatened or endangered species. Polar bear numbers are currently high and the population has been increasing rapidly in recent decades. Everyone likes polar bears, so this is good news. A decision to list would require forecasts that the current upward population trend will reverse. The government studies concluded that polar bear populations would decrease substantially.
Decision makers and the public should expect people who make forecasts to be familiar with the scientific principles of forecasting just as a patient expects his physician to be familiar with the procedures dictated by medical science. Three scientists, J. Scott Armstrong of the University of Pennsylvania, Kesten Green of Monash University, and Willie Soon of The Harvard-Smithsonian Center for Astrophysics, audited the government studies to assess whether they were consistent with forecasting principles. Their paper, “Polar Bear Population Forecasts: A Public-Policy Forecasting Audit,” has been accepted for publication in the management science journal Interfaces. It is the only peer-reviewed paper on polar bear population forecasting that has been accepted for publication in an academic journal.
They concluded that the government forecasts were based on false assumptions and their polar bear population forecasts contravened many principles for scientific forecasting. Indeed, the reports followed fewer than one-sixth of the relevant principles. Given the importance of the forecasts, all principles should be properly applied. In short, the government reports do not provide relevant information for this decision.
Research shows that for issues such as the population of polar bears—situations that are complex and where there is much uncertainty—the best forecast is that things will follow a “random walk;” in effect, this model states that the most recent value is the best forecast for all periods in the future. Because the polar bear population has been increasing over recent decades, however, a continuation of that trend over the short term is possible.
Copies of Armstrong, Green and Soon’s forthcoming paper are available at http://publicpolicyforecasting.com.
Transcript of Scott Armstrong’s Congressional Testimony
Following are portions of a transcript of Professor J. Scott Armstrong's testimony to the Senate Committe on Environment and Public Works, January 30, 2008. Armstrong explained how U.S. Government studies projecting future declining polar bear populations due to Arctic ice growth are seriously flawed by relying on complex sets of assumptions, and should not be considered to be scientific forecasts.
View a six minute video of Professor Armstrong's testimony
View the full transcript of Armstrong's testimony
...
My name is Scott Armstrong. I am a professor at the Wharton School of the University of Pennsylvania.
The decision on whether or not to list polar bears under the Endangered Species Act rests heavily on forecasting. I am addressing this Committee today as a forecasting expert.
I am a founder of the Journal of Forecasting and the International Journal of Forecasting, which are the two main journals that address the subject of forecasting. I am also a founder of the International Institute of Forecasters and of the International Symposium on Forecasting.
I have published more than 50 peer-reviewed papers on forecasting. My first book on the subject, Long-Range Forecasting, was published in 1978 and revised in 1985. I am the editor of Principles of Forecasting: A Handbook for Researchers and Practitioners (2001) and the founder and co-director of the forecastingprinciples.com website. I have been working on forecasting problems for 48 years.
...
Audit of Polar Bear forecasting
We conducted forecasting audits of two of the nine administrative reports that were prepared in 2007 to “...Support U.S. Fish and Wildlife Service Polar Bear Listing Decision.” We selected the reports Amstrup et al. and Hunter et al. as they appeared to be the primary forecasting documents.
Our concern was to establish whether the reports’ forecasts of the polar bear population over the balance of the 21st Century were the product of scientific procedures.
We found that the authors of both reports made complex sets of assumptions in order to derive their polar bear population forecasts. Critically, the authors assumed on the basis of general circulation model (GCM) forecasts that summer sea ice will diminish in the Arctic over the rest of the 21st Century. Green and Armstrong (2007) audited the procedures used by GCM climate modelers and found that their forecasts were not scientific. Forecasting sea ice conditions adds an additional level of complexity to the problem and the GCMs fail to reproduce actual sea ice conditions even when historical periods are simulated.
What if predictions about Arctic sea ice conditions over the 21st century turned out to be right? Would the polar bear forecasts then be useful? To assess this, each of the three authors of Armstrong, Green, and Soon (2008) used the forecasting audit software that is available on forecastingprinciples.com. ...
On average, the authors properly applied only 12% of relevant principles. In what occupations would work that follows 12% of proper procedures be considered acceptable?
...
Another example of what happens when principles are contravened
How did the authors of the Hunter et al. administrative report obtain forecasts of a rapidly diminishing polar bear population?
Consider again Exhibit 1. The labels that I will add show that these data represent the ice-free days in the Southern Beaufort Sea. None of the data shown in the exhibit were used by the authors to forecast the number of ice-free days over the 21st Century. Instead, they relied on a climate model (GCM) scenario of dramatically increasing numbers of ice-free days. This is in sharp contrast to what the data in the Exhibit seem to indicate.
Exhibit 3 shows the data with labels. It is reproduced from Figure 3 on page 26 of Regeher et al (2007), one of the nine USGS administrative reports.
Hunter and her colleagues then used only the five years of data indicated by the filled-in circles and polar bear population estimates for those years to conclude that there was a strong causal relationship between the number of ice-free days and the bear population growth rate.
Finally, they combined the GCM-originated ice-free-day scenario with their estimate of the effect of ice-free days (based on 5-years of data) in order to project the polar bear population over a period of nearly a century (Hunter, Figure 6). Their process ignored other influences on bear fertility and mortality.
Fully disclosed and peer reviewed
We have sought peer review from researchers and we are continuing to do so. The latest version of the working paper is always available at publicpolicyforecasting.com.
We sent our paper to all those whom we cited asking them if we had cited them correctly. This led to some changes and to a few suggestions on how to better describe what they had done.
Conclusions
To date, there are no scientific forecasts of the polar bear population over the 21st Century. Nor are there any forecasts to suggest that a decision to list them would produce benefits. I urge further study.
Other Links
National Center for Policy Analysis, May 17, 2006 - "Polar Bears on Thin Ice, Not Really!"
This article contains excerpts from a May 17, 2006 report by the “National Center for Policy Analysis” (NCPA) describing the current state of Polar Bear populations, showing that only small groups of bears are declining while the others are stable or increasing.
...
Interestingly, the World Wildlife Fund (WWF), an international organization that has worked for 50 years to protect endangered species, has also written on the threats posed to polar bears from global warming. However, their own research seems to undermine their fears. According to the WWF, about 20 distinct polar bear populations exist, accounting for approximately 22,000 polar bears worldwide. As the figure shows, population patterns do not show a temperature-linked decline:
— Only two of the distinct population groups, accounting for about 16.4 percent of the total population, are decreasing.
— Ten populations, approximately 45.4 percent of the total number, are stable.
— Another two populations— about 13.6 percent of the total number of polar bears— are increasing.
— The status of the remaining six populations (whether they are stable, increasing or decreasing in size) is unknown.
Moreover, when the WWF report is compared with the Arctic air temperature trend studies discussed earlier, there is a strong positive (instead of negative) correlation between air temperature and polar bear populations. Polar bear populations are declining in regions (like Baffin Bay) that have experienced a decrease in air temperature, while areas where polar bear populations are increasing (near the Bering Strait and the Chukchi Sea) are associated with increasing air temperatures. Thus it is difficult to argue that rising air temperatures will necessarily and directly lead to a decrease in polar bear populations.
Conclusion. Are human activities causing a warming in the Arctic, affecting the sea ice extent, longevity and thickness? Contradictory data exists. What seems clear is that polar bears have survived for thousands of years, including both colder and warmer periods. There may be threats to the future survival of the polar bear, but global warming is not primary among them.
This article contains excerpts from a May 17, 2006 report by the “National Center for Policy Analysis” (NCPA) describing the current state of Polar Bear populations, showing that only small groups of bears are declining while the others are stable or increasing.
...
Interestingly, the World Wildlife Fund (WWF), an international organization that has worked for 50 years to protect endangered species, has also written on the threats posed to polar bears from global warming. However, their own research seems to undermine their fears. According to the WWF, about 20 distinct polar bear populations exist, accounting for approximately 22,000 polar bears worldwide. As the figure shows, population patterns do not show a temperature-linked decline:
— Only two of the distinct population groups, accounting for about 16.4 percent of the total population, are decreasing.
— Ten populations, approximately 45.4 percent of the total number, are stable.
— Another two populations— about 13.6 percent of the total number of polar bears— are increasing.
— The status of the remaining six populations (whether they are stable, increasing or decreasing in size) is unknown.
Moreover, when the WWF report is compared with the Arctic air temperature trend studies discussed earlier, there is a strong positive (instead of negative) correlation between air temperature and polar bear populations. Polar bear populations are declining in regions (like Baffin Bay) that have experienced a decrease in air temperature, while areas where polar bear populations are increasing (near the Bering Strait and the Chukchi Sea) are associated with increasing air temperatures. Thus it is difficult to argue that rising air temperatures will necessarily and directly lead to a decrease in polar bear populations.
Conclusion. Are human activities causing a warming in the Arctic, affecting the sea ice extent, longevity and thickness? Contradictory data exists. What seems clear is that polar bears have survived for thousands of years, including both colder and warmer periods. There may be threats to the future survival of the polar bear, but global warming is not primary among them.
Christian Science Monitor, May 3, 2007 - "Canadian Controversy: How do polar bears fare?" This article explains the claims of two opposing scientific views concerning the link between polar bear population size and retreating ice in the Arctic.
http://www.csmonitor.com/2007/0503/p13s01-wogi.html
National Center for Policy Analysis, January 22, 2008 - "Warming World has Increased Polar Bear Numbers." A January 22, 2007 report by The National Center for Policy Analysis shows that polar bear populations have increased dramatically since the 1970s from about 5,000 to as many as 25,000 today--a five fold rate of increase. Also shown is the fact that Polar Bear populations have thrived in past temperature periods that are much warmer than the present.
http://www.ncpa.org/sub/dpd/index.php?Article_ID=14099
TheClimateBet.com - "Polar Bear Fears Groundless." This article explains how government forecasts concerning polar bear population sizes have been shown to have been based on assumptions and thus are not scientifically valid.
https://www.theclimatebet.com/?s=polar++bear+fears+groundless
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Issues with Polar Bears and Global Warming |
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