How does climate change contribute to sea level rise? | Ask A Scientist

Summary

In this episode of *Ask a Scientist*, Dr. Chris Derksen explains how climate change is driving sea level rise, which has increased by about 15 centimeters in the 20th century. He outlines two key causes: thermal expansion of ocean water due to rising temperatures and the melting of ice sheets in Greenland, Antarctica, and the Arctic. Future projections suggest an additional 40-85 centimeters by the end of the century, with possible increases of up to four meters by 2300, depending on emissions. Dr. Derksen emphasizes the need for adaptation and proactive policies to mitigate these impacts on coastal regions.

Takeaways

• 😀 Climate change is causing sea levels to rise due to two main factors: thermal expansion of ocean water and melting ice sheets.
• 🌊 Over the 20th century, sea level has risen by about 15 cm, with a current rate of increase of about 4 mm per year.
• 📉 Despite the small annual increase, over decades this rise becomes significant, posing a threat to coastal regions.
• 🏝️ Low-lying island countries and coastal infrastructure are at high risk from sea level rise and extreme events like storm surges.
• 🌡️ Warmer ocean temperatures from global warming lead to thermal expansion, contributing to sea level rise.
• ❄️ Melting ice sheets, including Greenland and Antarctica, contribute additional water to the oceans, further raising sea levels.
• 📈 Climate models suggest that by the end of the century, sea levels could rise by 40 to 85 cm, depending on carbon emissions pathways.
• ⚠️ Future carbon emissions policies will directly influence the extent of sea level rise and its associated impacts.
• 🌍 Longer-term projections indicate that by 2300, sea levels could rise by as much as 4 meters, causing substantial global impacts.
• 🔧 Engineering projects and adaptations will be crucial in protecting coastal areas and mitigating the effects of sea level rise.
• 🌍 Understanding and addressing climate change is essential to minimize future risks and safeguard vulnerable communities.

Q & A

How does climate change lead to sea level rise?

Climate change causes sea level rise through two main drivers: thermal expansion of ocean water due to higher temperatures and the melting of large ice sheets (such as in Greenland and Antarctica) and smaller glaciers, which adds more water to the ocean.

How much has sea level increased in the 20th century?

Sea level has increased by approximately 15 centimeters over the 20th century.

At what rate is sea level rising each year?

Sea level is currently rising at a rate of about 4 millimeters per year.

Why does 4 millimeters of sea level rise per year matter?

While 4 millimeters might seem small on its own, over time, this gradual increase adds up, leading to significant long-term changes in sea level, which can cause major impacts, especially for low-lying coastal areas.

What are some of the risks posed by rising sea levels?

Rising sea levels pose risks to low-lying island nations, coastal infrastructure, and communities. The threat is further compounded by extreme events like storm surges and high tides.

How do warmer ocean temperatures contribute to sea level rise?

Warmer ocean temperatures cause thermal expansion, meaning the water molecules spread out, which increases the volume of water in the ocean and raises the sea level.

What role do melting ice sheets play in rising sea levels?

When large ice sheets, such as those in Greenland and Antarctica, melt, the water that was previously stored as ice flows into the ocean, contributing directly to sea level rise.

What is the projected sea level rise by the end of this century?

By the end of the century, projections suggest that sea level will rise between 40 to 85 centimeters, depending on the carbon emissions pathway our planet follows.

How could climate emissions policies impact sea level rise in the future?

The amount of sea level rise depends heavily on global carbon emissions. If emissions are reduced, the rate of sea level rise will be lower, whereas higher emissions will lead to more significant rises.

What is the potential sea level rise by the year 2300?

Climate models suggest that by the year 2300, sea levels could rise by up to 4 meters, which would have catastrophic impacts on coastal regions worldwide.