Study finds direct link between greenhouse gas emissions and polar bear survival, scientists say

Fifteen years have passed since polar bears were designated as a threatened species, and now a groundbreaking study has revealed that researchers have successfully overcome a significant obstacle in the implementation of the Endangered Species Act.

This obstacle had previously prevented the federal government from taking climate change into account when evaluating the potential impacts of projects such as oil and gas drilling.

The act mandates that agencies must ensure that the projects they approve do not cause further harm to listed species.

However, a legal opinion issued by the Department of Interior in 2008 stated that greenhouse gas emissions did not need to be considered, as the specific impact of individual projects could not be distinguished from the cumulative effect of all historic global emissions.

Nevertheless, a study published in Science’s Policy Forum on Thursday has now demonstrated that scientists, for the very first time, are able to directly measure and quantify the impact of human-caused greenhouse gas emissions from specific sources on the survival of polar bear cubs.

This breakthrough represents a significant step forward in our understanding of the complex relationship between climate change and endangered species.

The assertion made by lead author Steven C. Amstrup, chief scientist emeritus at Polar Bears International and a professor at the University of Wyoming, that polar bears were listed due to the loss of sea ice caused by global warming, without considering emissions, appears rather peculiar.

This observation raises questions about the comprehensive evaluation of the factors contributing to the decline of polar bear populations.

While the loss of sea ice undoubtedly poses a significant threat to the survival of these majestic creatures, it is essential to acknowledge the broader context of global warming and its underlying causes.

By solely focusing on the consequences of sea ice reduction, we may be neglecting the root of the issue: the emissions that drive climate change.

Therefore, it is crucial to consider the multifaceted nature of this problem and adopt a holistic approach that encompasses all relevant factors in order to effectively address the challenges faced by polar bears and their ecosystems.

Polar bears, existing in 19 subpopulations across the Arctic, heavily rely on sea ice as their hunting grounds for seals.

However, the alarming rate at which ice is melting has forced these bears to either seek land or swim further from the shore in search of ice.

This unfortunate situation has had a detrimental effect on their ability to find food, resulting in prolonged fasting periods that deplete their fat reserves.

The primary cause of this ice loss is human-induced global warming, which has significantly reduced the number of sea ice days available for the bears to accumulate their vital fat reserves.

If this warming trend continues unchecked, scientists predict that the majority of polar bears could face extinction by the end of the century.

A recent study conducted in 2020 highlighted the direct correlation between the number of fasting days and the survival rate of polar bear cubs.

Building upon this finding, the authors of a new study sought to quantify the exact number of ice-free, fasting days caused by a specific amount of human-caused greenhouse gas emissions.

This distinction is crucial as it goes beyond the existing atmospheric concentrations and focuses on the emissions themselves, making it highly relevant for policy-making.

Cecilia M. Bitz, a co-author of the study and a climatologist and director of the climate change program at the University of Washington, emphasized the importance of considering emissions when formulating policies.

By estimating the relationship between the duration of fasting periods and each gigaton of cumulative emissions, the researchers were able to calculate the potential impact of emissions from specific projects on the survival of future polar bear cubs.

In conclusion, the plight of polar bears is a stark reminder of the devastating consequences of human-induced global warming.

The reduction in sea ice caused by melting has severely impacted the ability of these majestic creatures to find food, leading to extended fasting periods that deplete their fat reserves.

The urgency to curb emissions and mitigate the effects of climate change cannot be overstated.

By understanding the direct link between emissions and the survival of polar bear cubs, policymakers can make informed decisions to protect these iconic species and ensure their existence for future generations.

According to Amstrup, the connection between emissions, ice-free days, and the impact on polar bears is essentially a matter of connecting the dots.

He believes that this method can also be applied to other species like sea turtles or coral reefs. Furthermore, Amstrup argues that this study presents a strong case for rescinding the 2008 opinion that prohibits climate considerations.

He points out that the Endangered Species Act requires federal agencies to utilize the best available scientific data.

Unfortunately, there was no immediate comment from Interior officials on this matter. Nevertheless, Todd Atwood, a wildlife biologist leading the U.S.

Geological Survey’s polar bear research program, commends the study as an important initial step in quantifying the relationship between greenhouse gas emissions and polar bear survival.

Atwood believes that this study successfully provides a framework for further exploration in this area. However, he acknowledges the challenges in obtaining consistent estimates of population trends and survival rates for different polar bear subpopulations.

These subpopulations are spread across a vast geographic area with variations in sea ice and food sources, making it problematic to match recent greenhouse gas emission trajectories with population survival rates.

Atwood emphasizes that this is not a criticism of the study, but rather a reflection of the difficulties in accessing certain subpopulations due to limited funding.

According to Andrew Derocher, a polar bear expert and biological sciences professor at the University of Alberta, the study discussed in the previous section indicates a correlation between emissions and polar bear cub survival, rather than a direct cause and effect relationship.

While he believes that this research brings us closer to understanding the intricate relationships at play, Derocher does not believe that it presents a groundbreaking revelation that will significantly alter prevailing opinions.

Expressing concerns about the long-term risk of polar bear extinction, he does not consider this study to be the definitive evidence needed to change perspectives on the matter.

On the other hand, Dan Rohlf, a professor at Lewis and Clark Law School in Portland, Oregon, and an expert on the Endangered Species Act, commends the study for its significant contributions to understanding the impact of cumulative emissions on polar bears.

Rohlf agrees with the authors’ assertion that it is illogical to classify polar bears as threatened due to climate change, while simultaneously disregarding the consequences of federal actions that contribute to greenhouse gas emissions. In his view, this inconsistency lacks any semblance of logic.

In light of the current discourse surrounding federal agencies’ approach to assessing emissions, it is crucial to acknowledge the limitations of their methodology.

According to Rohlf, an expert in environmental policy, federal agencies tend to evaluate emissions on a project-by-project basis, disregarding the cumulative impact of multiple federal actions.

This singular focus on individual projects, each with relatively small emissions, fails to capture the broader picture of the combined effects of these actions.

Consequently, this approach may not provide an accurate representation of the true environmental impact of federal initiatives.

To ensure a comprehensive understanding of emissions and their consequences, it is imperative for federal agencies to adopt a more holistic approach that takes into account the cumulative emissions resulting from their collective actions.

Only then can we effectively address the environmental challenges we face today.

According to Rohlf, agencies like the Fish and Wildlife Service possess the power to ascertain the vulnerable status of polar bears and advocate for the reduction of greenhouse gas emissions.

This implies that project evaluations could take into account the extent to which emissions align with the objective of decreasing greenhouse gases.

However, Rohlf acknowledges that implementing such measures may encounter significant political opposition.

Despite the potential environmental benefits and the scientific evidence supporting the need for emission reduction, the feasibility of this approach may be hindered by political considerations.

According to a prominent expert in the field, the prevailing theory regarding the impact of adverse effects on a particular species suggests that these effects are allowed to accumulate incrementally until a critical point is reached.

At this juncture, the final adverse effect serves as the proverbial straw that breaks the camel’s back, necessitating immediate action to rectify the situation.

However, the expert argues that in the case of polar bears, we have already surpassed this critical point, and their very existence is now hanging in the balance.

Consequently, it is imperative that we take immediate and decisive measures to halt any further damage and ensure the survival of this iconic species.

The urgency of the situation cannot be overstated, and it is incumbent upon us to recognize the gravity of the issue and act accordingly.