## 24.3 Climate Inertia Why does Earth's temperature not immediately cool down, even if all greenhouse gas emissions were stopped today? The reason is **climate inertia**. This can be visualized like a massive ship: after the engines are turned off, the ship continues to coast for a long time due to its momentum. This section explains why Earth's climate has a similar built-in delay, primarily due to the vast amount of heat stored in the oceans, and why early action on climate change is crucial. ### Feedback Mechanisms - **Positive feedback**: Amplifies initial changes. Example: Arctic ice melt reduces Earth's reflectivity (albedo), leading to further warming. - **Negative feedback**: Dampens changes. Example: increased carbon dioxide ($\mathrm{CO}_2$) stimulates plant growth, absorbing some carbon. ### Time-Dependent Nature of Climate Inertia Climate processes operate on various timescales, from days to centuries. Even if greenhouse gas emissions stabilize immediately, Earth's climate would continue to warm due to heat already stored in the oceans. This phenomenon is often referred to as **Committed Warming**. - **Short-term Inertia**: Occurs due to the relatively slow absorption and release of heat by ocean and land surfaces, such as daily temperature fluctuations. - **Long-term Inertia**: Changes in greenhouse gas concentrations take decades to centuries to fully impact the climate system, such as $\mathrm{CO}_2$ emissions. ### Role of Oceans Oceans have a high heat capacity, meaning they absorb and release heat slowly. This **Thermal Inertia** means that gradual changes in ocean temperature affect climate patterns over extended periods, contributing significantly to the lag in the climate system's response. ### Carbon Cycle The carbon cycle involves the exchange of carbon dioxide between the atmosphere, oceans, land, and vegetation. It takes time due to processes like the slow decomposition of organic matter and the slow mixing of deep ocean waters, contributing to climate inertia. ### Melting of Ice Sheets and Glaciers The melting of ice sheets and glaciers contributes to sea level rise over centuries. Because ice takes a long time to melt even after temperatures rise, and because the ocean expands as it warms, sea-level rise is a primary long-term effect of climate inertia. ### Implications of Climate Inertia Climate inertia underscores the importance of both **adaptation** (adjusting to existing changes) and **mitigation** (reducing emissions) strategies. The effects of past emissions will persist even with immediate actions. If we stop all $\mathrm{CO}_2$ emissions today, the surface temperature will remain elevated for centuries. ### Components of Earth's Climate Change - Internal variations - External forcing Related sections: and .