Sharks and Climate Change: Past, Present, and Threats
Oceans are losing oxygen. Since the 1960s, warmer waters and excess fertilizers from human activities have caused a 2% drop in sea oxygen levels, severely impacting marine life.
Sharks Through Time
Sharks have existed for nearly 450 million years and adapted to various climates. Past sharks lived in oceans with higher temperatures or acidity than today. Unlike their ancestors, modern sharks cannot adapt quickly to rapid environmental changes caused by climate change.
How Sharks Are Affected by Climate Change
Human-induced climate change affects oceans in multiple ways: water temperature, acidity, sea level, currents, storms, and coastal erosion. These changes influence marine species’ food supply, distribution, migration, reproduction, and interactions within the food web. For sharks and rays, many of which are already endangered, climate change adds significant stress.
Key Threats to Modern Sharks
1. Climate Change and Reef Sharks
Sharks living in coral reefs are highly vulnerable. Rising ocean temperatures, increased acidity, and stronger storms threaten coral ecosystems. If reefs decline, reef sharks lose habitat and food sources, potentially putting them at risk of endangerment.
2. Shark Migration Changes
Warmer waters are altering shark migration patterns. Bull sharks, for instance, now appear in new locations previously outside their range. Such shifts can disrupt local ecosystems, threaten nursery areas, and affect predator-prey dynamics.
3. Impacts on Development
Warmer waters and higher carbon dioxide levels are linked to reduced shark growth and reproduction. Studies suggest that climate change may also affect brain development, altering behavior and decision-making, and resulting in smaller brains.
Conclusion
Climate change represents a growing threat to sharks, impacting habitats, migration, reproduction, and overall behavior. Protecting these apex predators requires monitoring, research, and conservation efforts to mitigate the rapidly changing conditions of the world’s oceans.
