Climate change: 400-year record heat threat to Great Barrier Reef | BBC News

Summary

Rising temperatures have led to the warmest decade in 400 years around Australia's Great Barrier Reef, causing five mass coral bleaching events in the last nine years. Scientists warn that the reef is in danger, urging immediate action against climate change. Despite international agreements, the situation remains dire, with the potential loss of many corals. However, scientists suggest that if action is taken now, parts of this natural wonder can still be preserved.

Takeaways

• 🌡️ Rising temperatures around the Great Barrier Reef have reached the highest levels in the last 400 years, according to scientists' analysis of coral skeletons and historical data.
• 🌊 The last decade has seen five mass coral bleaching events in the Great Barrier Reef, which is a significant increase compared to historical patterns.
• 🔍 Scientists have used long coral core samples to determine water temperatures during the reef's history, revealing a clear trend of increasing heat stress on the corals.
• 🏖️ The Great Barrier Reef is a vibrant and diverse underwater ecosystem that is currently being threatened by climate change.
• 💔 Bleached corals can recover, but if global warming continues at the current rate, they may not get the chance to do so, leading to long-term damage to the reef.
• 🌍 The findings from the Great Barrier Reef are consistent with global records indicating the impact of climate change on a worldwide scale.
• 📉 There is an urgent need for action to reduce carbon dioxide and other greenhouse gas emissions to mitigate further damage to coral reefs and other ecosystems.
• 📚 The study published in the journal Nature provides a reconstruction of sea temperatures that supports the urgency of the situation.
• 🌐 International agreements and targets to limit global warming are mentioned, but the emphasis is on the need to put politics aside and take immediate action.
• 🔄 While some coral growth may occur after bleaching events, the loss of older, slower-growing corals is a significant concern as they take centuries to mature.
• 📉 Discussions at UNESCO are ongoing to further protect the Great Barrier Reef, which is a world heritage site, but more decisive action is required to address the risks it faces.

Q & A

What is the current situation around the Great Barrier Reef in terms of water temperature?

The water temperatures around the Great Barrier Reef have been the warmest in the past 400 years over the last decade, leading to more mass bleaching events of the coral.

What does the report in the journal Nature indicate about the Great Barrier Reef?

The report in Nature shows that rising temperatures now threaten the survival of the reef, with scientists finding evidence of the warmest temperatures in the last decade compared to the past 400 years.

What happens to a coral reef when it becomes bleached?

When a coral reef bleaches, it turns very white quickly, and algae forms on top of the corals, which then turns them a brown color. This is not a natural or healthy state for the reef.

How did scientists determine the temperature conditions of the past for the Great Barrier Reef?

Scientists examined long coral cores samples drilled out of centuries-old coral bodies, which contain chemical clues that reveal historical water temperatures, combined with historical sea temperature records.

What is the significance of the Great Barrier Reef for the environment?

The Great Barrier Reef is a vast natural wonder and a colorful living underwater ecosystem that plays a crucial role in marine biodiversity and the overall health of the ocean.

What are the consequences if the current rate of global warming continues?

If the current rate of global warming continues without respite in high temperatures, the bleached, heat-stressed coral may not recover, threatening the survival of the reef.

What actions are being taken to address the crisis on the coral reefs?

Actions include discussions at UNESCO to protect the Great Barrier Reef as a world heritage site and the need for governments, individuals, and international bodies to move away from fossil fuels to reduce carbon dioxide and other greenhouse gas emissions.

What does Mark Eaken from the International Coral Reef Society suggest needs to happen urgently?

Mark Eaken suggests that there is a need for more urgency in moving off of fossil fuels and reducing heat-trapping gases in the atmosphere to stabilize the situation for coral reefs.

What is the impact of mass coral bleaching events on the ecosystem?

Mass coral bleaching events can lead to the death of most corals in an area. While fast-growing corals may recover quickly, the loss of older, slower-growing corals can take centuries to replenish, impacting the ecosystem's balance and diversity.

Are there any signs of new coral growth on the Great Barrier Reef despite the bleaching events?

There is some recovery and growth of fast-growing 'weedy' corals, but the older, 400-year-old corals that are critical to the reef's health and diversity take much longer to grow back and cannot be replaced within a few years.

What is the role of international agreements and targets in combating climate change affecting coral reefs?

International agreements and targets aim to limit global warming, which is crucial for saving parts of the natural wonder like the Great Barrier Reef. However, even if these targets are met, many corals are likely to be lost, emphasizing the need for immediate action.