How 2023 Broke Our Climate Models with Neil deGrasse Tyson & Gavin Schmidt

Summary

In this episode of *StarTalk*, Neil deGrasse Tyson and co-host Paul M. Sero are joined by Gavin Schmidt, Director of NASA's Goddard Institute for Space Studies, to discuss the alarming state of global climate change. They explore 2023 as the hottest year on record, driven by rising greenhouse gases and natural phenomena like El Niño. Schmidt explains the role of climate models, the impact of aerosols, and the challenges of predicting future temperatures. The conversation highlights both the urgency of addressing climate change and the potential for human action to mitigate further warming and control the planet's future.

Takeaways

• 😀 Gavin Schmidt, director of NASA's Goddard Institute for Space Studies, explains that 2023 was the hottest year on record, with temperatures surpassing previous highs by a significant margin.
• 🌍 Climate measurements are gathered from weather stations, ocean ships, and floating buoys that track ocean temperatures at various depths, forming a comprehensive data set dating back to the late 19th century.
• 🌡️ Global temperatures have been steadily rising since the 1970s, driven by human activities like the increase in carbon dioxide (CO2) and methane emissions.
• 🔬 Climate models, which predict future temperatures, did not foresee the rapid acceleration of warming in recent years, indicating uncertainties in long-term predictions.
• 🌞 Solar activity plays a role in Earth’s climate, but its effect on global temperatures is relatively small compared to greenhouse gases, with solar cycles influencing radiation output every 11 years.
• 💨 Aerosols—small particles from pollution, dust, and sea salt—reflect sunlight and cool the atmosphere. The reduction in pollution has led to fewer aerosols, contributing to additional warming.
• ⚠️ Geoengineering, such as reintroducing aerosols into the atmosphere to cool the Earth, could have unpredictable consequences and requires constant intervention, potentially for centuries.
• 🌊 The ocean plays a crucial role in climate change by absorbing about half of the CO2 emissions. This creates a balancing act where removing CO2 from the atmosphere also affects the ocean's carbon levels.
• 🧑‍🤝‍🧑 Despite the alarming rise in global temperatures, Gavin emphasizes that humans have the power to influence the future through actions like reducing CO2 emissions and curbing deforestation.
• 🌱 If global CO2 emissions are halted, the warming trend can be stabilized. This highlights the importance of collective global action to manage climate change.
• 🔮 While current predictions may be uncertain, the future of the planet is still in humanity’s hands, and responsible decisions can significantly mitigate further climate damage.

Q & A

What is the main reason for the 2023 being the hottest year on record?

2023 became the hottest year on record due to a combination of long-term warming trends driven by increased greenhouse gases like carbon dioxide and methane, as well as natural factors like an El Niño event. This marks a significant new record, surpassing previous highs by a large margin.

How are global temperatures measured, and how reliable are these measurements?

Global temperatures are measured through a network of weather stations, ocean buoys, and satellite data that track both surface and ocean temperatures. The data is compiled to produce long-term records of temperature trends, offering high reliability since it includes over 150 years of data, though some uncertainties remain.

What is the role of El Niño and La Niña in shaping global temperature predictions?

El Niño and La Niña are natural climate phenomena that influence global temperatures. El Niño, a warming event in the tropical Pacific, tends to increase global temperatures, while La Niña, a cooling event, can decrease temperatures. These events often shape predictions, but the intensity and timing of their effects can still be difficult to predict accurately.

Why are aerosols in the atmosphere significant for climate models?

Aerosols, such as dust, sea salt, and pollution particles, play a significant role in climate models because they reflect sunlight away from Earth's surface, thus cooling the planet. The decrease in air pollution over recent decades has led to fewer aerosols, contributing to additional warming, which was not fully accounted for in earlier models.

What unintended effect has the reduction in air pollution had on global warming?

The reduction in air pollution has had the unintended consequence of increasing global warming. Historically, aerosols from pollution helped cool the planet by blocking sunlight, but as pollution has been reduced through cleaner technologies, this cooling effect has diminished, leading to more warming.

What are the potential risks of geoengineering solutions like aerosol reintroduction?

Geoengineering solutions like aerosol reintroduction could have serious risks, primarily because once implemented, they may need to be sustained indefinitely to prevent rapid warming. Stopping the process could lead to a sudden and severe temperature increase, which makes it an unreliable and dangerous long-term solution.

How does the solar cycle influence global temperatures, and what is its current phase?

The solar cycle, which lasts about 11 years, influences global temperatures through variations in solar radiation. At solar maximum, the sun's energy output increases slightly, which can affect the Earth's temperature. Currently, the solar cycle is approaching its maximum, but its effect on global warming is relatively small compared to the influence of greenhouse gases.

What is the impact of removing CO2 from the atmosphere on the oceans?

When CO2 is removed from the atmosphere, about half of it is absorbed by the oceans. This creates a feedback loop where changes in atmospheric CO2 levels directly impact the ocean's CO2 content. However, the removal of CO2 does not entirely eliminate the atmospheric and oceanic CO2; it just reduces the concentration in both.

What challenges do scientists face in predicting the future climate?

Scientists face several challenges in predicting future climate, including the complexity of climate models, the unpredictable behavior of natural climate systems like El Niño, and uncertainties about the future emissions of greenhouse gases. Additionally, factors like aerosols and solar cycles add another layer of complexity to accurate predictions.

What is the key message from Gavin Schmidt regarding the future of climate change?

Gavin Schmidt emphasizes that, despite the uncertainties, humanity still has control over the future climate. If we reduce greenhouse gas emissions, we can prevent further warming. The future is not set in stone, and through collective action, we can influence the trajectory of global temperatures, though achieving global cooperation remains a significant challenge.