Every year, thousands of sea turtles migrate to the beaches of the Asia and Pacific region to lay their eggs. This is called the nesting season, and it usually occurs between November and February. When I visited the Philippines in January 2024, the first batches of sea turtle hatchlings had just emerged from their eggs. Volunteers from the Pawikan Conservation Center in Morong, Bataan monitor and protect the sea turtle hatchlings until they are ready to be released into the ocean. I arrived in Morong with my partner and together we volunteered to release a couple of Hawksbill sea turtle hatchlings.
The Pawikan Conservation Center is one of the many organizations in the Asia and Pacific region that are working to protect sea turtles. The center is located in the province of Bataan, which is about 3 hours away from Manila. The center is open to the public and offers educational tours and volunteer programs. The center also has a hatchery where they incubate sea turtle eggs and release the hatchlings into the ocean. The center is also home to a few adult sea turtles that are being rehabilitated before they are released back into the ocean.
The State of the World's Sea Turtles (SWOT) database maintains a list of sea turtle nesting sites around the world. The database is a collaborative effort between the Marine Turtle Specialist Group of the International Union for Conservation of Nature (IUCN) and the Marine Geospatial Ecology Lab at Duke University.
Sea turtles are an important part of the marine ecosystem. They help maintain the health of seagrass beds and coral reefs, which are important habitats for many marine species. Sea turtles also help control jellyfish populations, which can become a problem when they are not kept in check. Unfortunately, sea turtles are facing many threats, including habitat loss, pollution, and climate change. The warming climate is particularly concerning because it affects the gender of sea turtle hatchlings.
Unlike most species, the sex of a sea turtle hatchling is determined by the temperature of the sand where the eggs are incubated. Research has shown that if a sea turtle egg is incubated at a temperature below 81.86°F (27.7°C), the hatchling will be male, and if the egg is incubated at a temperature above 88.8°F (31°C), the hatchling will be female. If the temperature is in between the two thresholds, this will produce a mix of male and female hatchlings. This is called temperature-dependent sex determination.
According to a study by the University of Exeter and the Marine and Environmental Sciences Centre in Portugal, by the year 2100, rising temperatures could cause up to 93% of green sea turtle hatchlings to become female. This is concerning because it could lead to a decline in the populations of sea turtles.
But we need not wait for 2100 to see how this is affecting sea turtle hatchlings now. 99% of green sea turtles in Australia's northern Great Barrier Reef are female according to a report in the Current Biology journal in 2018.
Climate change is a global issue, and it is important to understand how it affects different species. By mapping out sea turtle nesting locations and the annual global climate report, we can see how the warming climate is affecting these sites.
2023 was the world's warmest year on record according to the Annual Global Climate Report by the National Oceanic and Atmospheric Administration. The Earth's average land and ocean surface temperature was 2.12°F (1.18°C) above the 20th century, with November 2023 being the warmest November in NOAA's 174-year record. November just so happens to be the start of sea turtle nesting season.
The NOAA global climate report shows how the warming climate is affecting sea turtle nesting locations in the Asia and Pacific region. The map shows the sea turtle nesting locations in the region and the average global temperature for November. Land and Ocean temperatures in countries in Southeast Asia with sea turtle nesting sites have increased by 0.55 °F above 57°F.
Data from NOAA only shows the land and ocean average temperatures in a given month and does not reflect the actual temperature of the sand where the sea turtles are incubating their eggs. But a 1.84 °F increase in the land and ocean temperature of the Philippines on November 2023, the month when nesting season begins, could have an affect on the temperature in sea turtle nesting sites.
As the climate continues to warm, it is important to monitor how it affects sea turtle populations. By understanding how the warming climate is affecting sea turtles, we can take steps to protect these important species.
