What Will Our World Look Like at 4 Degrees?

Summary

This video explores the urgent threat of sea level rise driven by climate change, focusing on the accelerating impact of carbon dioxide emissions. It examines historical data showing the potential for massive sea level increases and presents projections for the future, with possible rises of up to 10 meters by 2150. Coastal cities like Miami, New York, and Shanghai face significant flooding risks, displacing millions. The video highlights the importance of immediate action to reduce greenhouse gas emissions and shift to renewable energy in order to mitigate the worst effects of rising seas.

Takeaways

• 😀 The last time atmospheric carbon dioxide levels were similar to today's, sea levels were much higher, and many coastal regions were submerged.
• 🌎 The Earth’s oceans adjust slowly to temperature changes, and sea levels will continue rising for centuries due to melting ice caps and thermal expansion.
• 📈 If CO2 emissions stop today, sea levels are still projected to rise significantly, with some regions experiencing catastrophic flooding within this century.
• 🌍 Scientists use ancient ice samples to understand how rapidly CO2 levels are increasing and how they compare to past climate conditions.
• 🔬 CO2 emissions today are rising 10 times faster than at any point in the last 100,000 years, contributing to unprecedented climate change.
• 🏝️ Even with relatively small sea-level rises (e.g., one foot), millions of people living in low-lying coastal areas will be affected by floods and displacement.
• 🌊 Climate models predict up to 10 meters of sea level rise could occur, submerging cities like New York, Miami, and large parts of southern Florida.
• 🏘️ In the U.S., cities like New York, Long Island, and Norfolk could be underwater if sea levels rise by 10 meters, displacing millions of people.
• 💡 Sea level rise is caused primarily by two factors: melting land-based ice (Antarctica, Greenland, and glaciers) and thermal expansion of water.
• 🌡️ In the next 30 years, sea levels are projected to rise by approximately one foot, significantly impacting coastal communities and infrastructure.
• ⚠️ By 2150, if current trends continue, sea levels could rise by 6-7 feet, causing catastrophic flooding and necessitating the evacuation of major cities like New York, Miami, and New Orleans.
• 🌱 While the situation is dire, achieving net-zero emissions could drastically slow the rise of sea levels and mitigate future impacts, especially if renewable energy adoption accelerates.

Q & A

What happens to sea levels as Earth’s temperatures rise?

As Earth's temperatures rise, the heat energy melts ice caps and glaciers, causing sea levels to rise. The oceans slowly adjust to a new equilibrium once the temperature stabilizes.

How much higher were sea levels in the past when CO2 levels were similar to today?

During periods with similar atmospheric CO2 levels to today, sea levels were 5 to 10 meters higher than they are currently.

What is the primary cause of current sea level rise?

The main causes of current sea level rise are twofold: land-based ice melt (from Antarctica, Greenland, and mountain glaciers) and thermal expansion of water as it warms.

What is the difference between thermal expansion and ice melt in contributing to sea level rise?

Thermal expansion occurs when water warms and takes up more space, while ice melt is the loss of mass from ice sheets. In recent times, ice melt has outpaced thermal expansion in contributing to sea level rise.

How much have sea levels risen in the last 30 years, and how much more is expected in the next 30 years?

Sea levels have risen about four inches in the last 30 years. In the next 30 years, they are projected to rise by about one foot.

What are the projected impacts of a 10-meter sea level rise in the U.S.?

A 10-meter sea level rise could submerge parts of New York, Long Island, and New Jersey, with many major cities, including Miami and Southern Florida, being completely underwater. About 10 million people in Florida alone could be displaced.

What areas around the world would be most affected by a 10-meter sea level rise?

A 10-meter rise in sea levels would submerge much of Bangladesh, Bangkok, Shanghai, Hanoi, and Singapore, as well as large portions of the Gulf Coast.

What role do glaciers and ice sheets play in sea level rise, and how is their behavior changing?

Glaciers and ice sheets contribute to sea level rise by melting into the ocean. Their melt rates are accelerating, and the potential collapse of large ice sheets could significantly speed up the rise in sea levels in the future.

What are the likely scenarios for sea level rise by 2100 and 2150?

By 2100, sea levels are expected to rise by around three feet on average under the current emissions scenario. By 2150, if greenhouse gas emissions remain high, the rise could be as much as 6 to 7 feet in certain areas.

What is the potential for large-scale relocation as sea levels rise?

As sea levels rise, some coastal communities may have to relocate, especially those in areas already below sea level, like New Orleans. While some will be protected by levees, others may face catastrophic risk and need government relocation support.