How do you count all the polar bears in the Arctic? | Rod Downie | TEDxBrighton
The speaker argues that despite polar bears being a potent symbol of climate change, current population estimates are highly uncertain, requiring innovative scientific techniques. She details three successful methods—genetic mark-recapture, eDNA from footprints, and thermal infrared cameras—to improve census accuracy for conservation efforts. The overall goal is to use scientific understanding to inform conservation action before the Arctic's sea ice disappears within a generation.
## Speakers & Context
- Speaker (unnamed scientist); employed by WWF, focusing on Arctic conservation.
- Colleague: Mike (laboratory technician); works for the government of Nunavut, Canada.
- Location: Sea ice in the Canadian Arctic, near the indigenous Inuit community of Resolute Bay (about 100 miles northeast).
- Date: April 6, 2016.
- Conditions: Temperature of about minus 37 degrees; polar bear encountered weighing about seven times the speaker's body weight.
## Theses & Positions
- The conservation of polar bears requires answering fundamental, unanswered questions in polar bear science.
- Understanding the current population size and future response of polar bears to climate change is critical for conservation planning.
- Current scientific consensus is that the Arctic is experiencing rapid decline in sea ice, which polar bears depend upon.
- Solving the population count mystery requires employing advanced, creative, and innovative scientific partnerships.
## Concepts & Definitions
- **Sea ice dependence:** Polar bears have evolved to live on and around sea ice, which is rapidly declining.
- **Genetic mark-recapture:** Method involving taking a small biopsy sample (skin, hair, fat) from a bear's haunch via a dart for DNA analysis, providing a unique genetic fingerprint.
- **Environmental DNA (eDNA):** Ability to extract and analyze genetic markers from environmental samples, such as melted snow or water.
- **Chukchi Sea:** Geographic area covering about 600,000 square kilometers, connecting Eastern Russia to Alaska.
- **Climate-altered future:** The projected environment showing dramatic changes in the Arctic, including sea ice disappearance.
## Mechanisms & Processes
- **Population estimation:** Attempting to determine total wild bear counts in a vast, remote, and unforgiving area.
- **Genetic fingerprinting:** Process of analyzing DNA from biological samples to provide an individual bear's unique genetic identifier, allowing population size calculation through aggregating fingerprints.
- **eDNA extraction:** Process where scientific personnel collect samples (e.g., melted snow) to test for the presence of specific DNA markers from organisms that left the trace.
- **Thermal infrared imaging:** Attachment of specialized cameras to aircraft to detect minute temperature differentials, aiding in the visualization and counting of wildlife.
## Timeline & Sequence
- **Historically:** Polar bears have evolved over millennia to live on sea ice.
- **Current Status:** The Arctic is ground zero for climate change, and sea ice is in rapid decline.
- **Prediction:** The Arctic could be virtually free of sea ice during the summer months within a generation by **2040** or sooner.
- **Future Population:** Predicted polar bear population decline of about **30%** by the middle of the century.
- **Census Work (Example 1):** April **2016** in McClintock Channel, Nunavut, Canada, surveying an area of **300,000 square kilometers** (size of the UK).
- **Census Work (Example 2):** **2014** in Svalbard, Norwegian Arctic, collecting samples from footprints in the snow.
- **Census Work (Example 3):** May **2016** in the Chukchi Sea, partnering with Russian scientific research institutes.
## Named Entities
- **Nunavut:** Territory in Canada where the census work took place.
- **Resolute Bay:** Small indigenous Inuit community near the study site.
- **McClintock Channel:** Area in Nunavut where the first census was conducted.
- **Svalbard:** Location in the Norwegian Arctic where footprint samples were collected.
- **Chukchi Sea:** Area between Eastern Russia and Alaska used for aerial survey.
- **Inuit:** Indigenous people from the region.
- **WWF:** World Wildlife Fund; the speaker's organization.
- **US and Russian scientific research institutes:** Partners in the Chukchi Sea survey.
## Numbers & Data
- Date of observation: **April 6, 2016**.
- Location distance: **100 miles** northeast of the current spot.
- Polar bear weight comparison: **seven times** the speaker's body weight.
- Polar bear teeth count: **42** razor-sharp teeth.
- Initial global bear estimate range: **22 to 31,000**.
- Sea ice data source: **Cryosat-2** satellite.
- Projected bear decline: **30%** by the middle of the century.
- McClintock Channel sample area: **300,000 square kilometers**.
- Biopsy sample size: **5 millimetre** sample of skin, hair, and fat.
- Bear observation grid altitude: **400 feet**.
- Chukchi Sea area: **600,000 square kilometres**.
- Aerial survey altitude: **a thousand feet**.
## Examples & Cases
- **Polar Bear Encounter:** Witnessing a large adult male polar bear weighing about seven times the speaker's weight, which was exhibiting behaviors indicative of hunger and fear.
- **Genetic Mark-Recapture:** Flying grids, firing a non-lethal dart at the bear's haunch to collect a sample, which is then analyzed for a unique genetic fingerprint to calculate population size.
- **eDNA from Footprint:** Collecting snow samples from a polar bear footprint in Svalbard, which allowed scientists to reconstruct that the bear had fed on a ringed seal while a gull scavenged the carcass.
- **Thermal Imagery Comparison:** Comparing a high-resolution photograph (where the bear is visible) with the same location captured using a thermal infrared camera (where the bear is much harder to detect).
- **Lobsterman Documentary Analogy:** The initial struggle to quantify the bears' presence compared to the detailed work done on the lobstermen documentary.
## Tools, Tech & Products
- **Helicopter:** Used for flying survey grids at various altitudes.
- **Dart:** Used to harmlessly take a skin biopsy sample from a bear's haunch.
- **Cryosat-2:** Satellite used to pass over the Arctic, taking daily photographic records of sea ice extent.
- **Genetic sequencing laboratory:** Facility that processes biopsies to generate DNA fingerprints.
- **Thermal infrared cameras:** Specialized cameras attached to aircraft for detecting heat signatures, used in aerial surveys.
- **High-resolution aerial survey cameras:** Used concurrently with thermal cameras to capture standard photographic evidence.
## References Cited
- **WWF:** World Wildlife Fund; source of the speaker's affiliation and conservation drive.
- **Government of Nunavut:** Partner in the genetic mark-recapture census in McClintock Channel.
- **Norwegian polar Institute:** Partner in collecting snow samples in Svalbard.
- **Spy Jen:** French company utilized for environmental DNA analysis from snow.
## Trade-offs & Alternatives
- **Biopsy vs. non-invasive methods:** Genetic mark-recapture is highly accurate but requires physical sampling (biopsy).
- **Thermal vs. Optical Imaging:** Thermal cameras are excellent for detecting living signatures, but high-resolution cameras provide comprehensive detail (though the bear might blend in optically).
- **Aerial Surveying:** Using aircraft is necessary for covering vast areas like the Chukchi Sea, but the process requires multiple specialized tools (multiple camera types).
## Methodology
- **Three-pronged Census Strategy:** Implementing three distinct, mutually reinforcing scientific approaches:
1. Genetic Mark-Recapture (physical biopsy and DNA analysis).
2. Environmental DNA (analyzing trace materials like melted snow).
3. Remote Sensing (aerial surveys using thermal infrared and high-resolution cameras).
- **Collaboration:** Success relies on building partnerships with indigenous communities (Inuit), national governments (Nunavut), and international scientific bodies (Russian institutes).
## Conclusions & Recommendations
- To ensure a future for polar bears, humanity must tackle climate change to stabilize the Arctic environment.
- Scientists must continue to combine human ingenuity with advanced technology and local knowledge to fill critical knowledge gaps.
- Speakers urge the audience to be driven by science and inspired by nature in their own fields.
## Implications & Consequences
- Failure to address climate change will lead to the loss of sea ice, resulting in a predicted 30% drop in the polar bear population by the mid-century.
- The success of these methods means that the biological and physical understanding of polar bears can guide direct conservation planning.
- The fate of the polar bear serves as a direct indicator of the health and stability of the entire Arctic ecosystem.
## Verbatim Moments
- *"My colleague's name is Mike and he is a laboratory technician he works for the government of nunavut in Canada"*
- *"the first and perhaps the most important of those was just how lucky I am to be working for WWF the most exciting and the most relevant conservation organization in the Arctic"*
- *"i didn't need to run as fast as Usain Bolt i just needed to run faster than my colleague Mike"*
- *"we just don't know with any degree of certainty how many polar bears there are on our planet"*
- *"the Arctic is ground zero for climate change and sea ice is in rapid decline and we know this with absolute scientific certainty because there are satellites such as cryosat-2"*
- *"so in just over 30 years from now we may have lost a third of all the polar bears on our planet"*
- *"it's completely harmless to the polar bear"*
- *"we have absolutely isolated genetic markers of polar bears"*
- *"this is science just in a teaspoonful of snow"*
- *"If there's one thing that terrifies me more than coming face-to-face with a polar bear it's the thought that my son Callum who is just four years old might not come face-to-face with polar bears on Arctic sea ice when he is my age"*
- *"I hope that when you leave the room at the end of today that you will continue like me to be driven by science and inspired by nature"*