Future reduction of sea ice in the Arctic could result in a loss of 2/3 of the world’s polar bear population within 50 years according to a series of studies released today by the U.S. Geological Survey.

Last December, Secretary of the Interior Dirk Kempthorne announced that the U.S. Fish and Wildlife Service was proposing to list the polar bear as a threatened species under the Endangered Species Act. In January 2008, following a one-year review period, the Service is expected to make a recommendation to Secretary Kempthorne on whether or not to list the polar bear as threatened. What would make this listing special is that it would be the first based solely on global warming threats to a species. Something the Bush administration is reluctant to do based on its “put your head in the sand” policy on climate change. Saying the polar bear is threatened because of global warming, is a lot like saying global warming is real, you see the dilemma for them. If they admit that we are to blame for the plight of the polar bear, then some might say we should do something to stop it.

To assist the Service in making that recommendation, Secretary Kempthorne requested USGS leadership in studies to inform the Service’s deliberations on polar bear status. This information summarizes and integrates the results from a series of studies on polar bear populations, range-wide habitats and changing sea ice conditions in the Arctic.

In making the announcement last December, Secretary Kempthorne said: “I am directing the U.S. Fish and Wildlife Service and the U.S. Geological Survey to aggressively work with the public and the scientific community over the next year to broaden our understanding of what is happening with the species. This information will be vital to the ultimate decision on whether the species should be listed.”

Specifically the USGS has improved knowledge on the status of three polar bear sub-populations, projected numbers of polar bears into the future in relation to sea ice and integrated the information into a range-wide assessment of polar bear status under scenarios of future climate change.

The newly-released USGS information, presented to the Service in the form of nine administrative reports to be open for public comment, will now be considered within the context of the Fish and Wildlife Service’s one-year review. The report just happened to be released at about the same time that General Petraeus was giving his Iraq report. I am certain they did this so that both reports would get the full media attention they deserve (sarcasm). The Service will analyze it and other information provided by scientists, government agencies and the public in order to arrive at an informed and scientifically justifiable decision. That decision is due in January.

During a six-month period of intensive analysis of both existing and new data, the team documented the direct relationship between the presence of Arctic sea ice and the survival and health of polar bears. Polar bears depend on sea ice as a platform to hunt seals, their primary food. But sea ice is decreasing throughout their Arctic range due to climate change. Models used by the USGS team project a 42 percent loss of optimal polar bear habitat from the Polar Basin during summer, a vital hunting and breeding period, by mid-century. In other words, no ice no bears, and the ice is on its way out.

In addition to forecasts, declines in habitat have been recorded throughout the Polar Basin over the past 20 years of observations. To project future sea ice conditions, USGS scientists used 10 general circulation models that best approximated observed trends in sea-ice loss and could be expected to do the best job of simulating future conditions. Scientists characterize their conclusions as conservative because even the best available models are believed to underestimate the actual decline in Arctic sea ice.

Below are the key findings from the executive summary. (pdf)

1. We divided the range of the polar bear into 4 ecoregions based on major differences in current and projected sea ice conditions. These “ecoregions” were the:

* Seasonal Ice Ecoregion which includes Hudson Bay, and occurs mainly at the southern extreme of the polar bear range,

* Archipelagic Ecoregion of the Canadian Arctic,

* Polar Basin Divergent Ecoregion where ice is formed and then drawn away from near-shore areas, especially during the summer minimum ice season, and

* Polar Basin Convergent Ecoregion where sea ice formed elsewhere tends to collect against the shore.
Dividing the range of the polar bear into these 4 ecoregions allowed us to make inferences from available knowledge about subpopulations in each ecoregion to the entire ecoregion.

2. We incorporated projections of future sea ice in each ecoregion, based on 10 general circulation models (GCMs), chosen from among 20 available. These 10 models did the best job of simulating current ice conditions and thus could be expected to do the best job of simulating future ice conditions. Use of 10 models allowed us also to incorporate the considerable variability among the models in our analyses for future polar bear habitat and populations. We used outputs for “business as usual” greenhouse gas forcing, known as the SRES-A1B scenario, for most of our analyses.

3. An important conclusion from a review of current knowledge about sea ice and sea ice modeling is that Arctic sea ice decline is likely underestimated by the available models.

4. Based on new findings from the Northern Beaufort subpopulation, polar bear subpopulations in the convergent ice ecoregion of the polar basin are likely currently stable; most available information about the status of populations living in the 4th ecoregion, the archipelagic ecoregion, suggests relative stability.

5. For two subpopulations of polar bears, Western Hudson Bay in the seasonal sea ice ecoregion, and Southern Beaufort Sea in the divergent ecoregion, it is now possible to relate declines in the availability of sea ice to declines in metrics of population status.

6. Knowledge of how polar bear population growth rates relate to specific changes in sea ice (e.g., length of the ice-free season) provides a mechanism for developing projections of future populations under different sea ice scenarios.

7. Under a range of future sea ice scenarios for the 21st century and modeling approaches, the Southern Beaufort Sea subpopulation of polar bears is projected to decline severely by the end of the century, and in many scenarios, by mid-century.

8. Polar bears primarily use sea ice over the continental shelf. They also prefer ice that is greater than 50% in concentration. Taking these habitat features into account, we projected future polar bear habitat within the polar basin for the divergent and convergent ice ecoregions using the available sea ice models. We also evaluated how availability of polar bear habitat in the polar basin has changed in recent years.

9. Optimal habitat in the polar basin (including both the divergent and convergent ice ecoregions) declined between the early (1985-1995) and latter decades (1996-2006) of the observational record of sea ice (based on passive microwave data). Most pronounced polar bear habitat loss in the past decade has occurred in peripheral seas of the Arctic Ocean–the Chukchi Sea and Barents/Greenland Seas.

10. Similarly, we projected losses of polar bear habitat within the polar basin to be greatest for the peripheral seas of the polar basin (e.g., the Chukchi Sea and Barents Sea).

11. The largest reductions in habitat in the polar basin are predicted for spring and summer. Sea ice will reform each winter, but the large retreats of sea ice in summer may ultimately preclude bears from returning to onshore denning habitat. Low productivity of the polar basin appears to preclude bears from adapting a seasonal ice lifestyle here.

12. Ultimately, we projected a 42% loss of optimal polar bear habitat during summer in the polar basin by mid century.

13. Due to unavailability of telemetry data showing habitats chosen by polar bears in the archipelagic and seasonal sea ice ecoregions, we were unable to project habitat changes in these ecoregions for this analysis.

14. Using a simple deterministic model of future carrying capacity for polar bears, we forecasted that polar bears could be extirpated in the divergent ice ecoregion within 75 years, assuming that sea ice decline follows the mean trajectory predicted by the 10 models we used. If sea ice decline follows the minimum trajectory predicted, extirpation in this ecoregion could occur by year 45.

15. Using the carrying capacity model, we projected populations of polar bears in all other ecoregions to decline at all time steps, with severity of decline dependent upon whether minimum, maximum or mean ice projections were used. The only exception was a slight, temporary, increase in the polar basin convergent ice ecoregion for the 45 year timestep and the maximum ice scenario.

16. Based on a first-generation Bayesian Network model incorporating a range of factors affecting polar bears, we forecasted extirpation of polar bear populations in the seasonal sea ice and the polar basin divergent ecoregions by 45 years from present.

17. We forecasted extirpation of polar bear populations in the polar basin convergent ecoregion by 75 years from present. In the archipelagic ecoregion, polar bears could occur through the end of the century, but in smaller numbers than now.

18. Sea ice conditions would have to be substantially better than even the most conservative GCM projections to result in qualitatively different outcomes for polar bears in any of the ecoregions.

So there you have it, the mighty polar bear could be almost half wiped out in the next 20-30 years. If you are reading this right now, there is a very good chance you could one day live in a world in which the only polar bears are on old coke commercials. I guess we could throw up our hands and proclaim our meek acceptance of this fact. Or we could get really pissed off and swear and scream.

I propose that instead we get even. If our leaders (who in theory represent us) are not going to do what we want, I say we fire their asses. Before we vote them out of office first perhaps we should let them know how we feel. Calling your senator, or representative doesn’t take much time. It is something you could easily do once a week. Get some of your friends to help you out, and before you know it your senator will start calling you. Asking your opinion. One of the best ways to fight against global warming is to be an active and involved citizen. And I assure you, just because they are senators doesn’t mean they know anymore about this topic than you do. It is up to all of us to counter the messages these people get from big oil/coal/gas. The only way to do that is to speak up. Don’t do it for me, do it for the polar bears.