(Ch. 15) - Global Climate Change

Weather

Refers to short-term temperature & precipitation patterns over days & weeks.

Climate

Refers to the long-term average temperature & precipitation patterns in a specific region.

Carbon Cycle

The process of carbon moving through the Earth's systems, including the atmosphere, biosphere, geosphere, hydrosphere, and cryosphere.

Biological Carbon Cycle

Involves living organisms, primarily through processes like photosynthesis & respiration.

Geochemical Carbon Cycle

Involves the movement of carbon through rocks, sediments, & fossil fuels over long time scales.

Non-anthropogenic ways to unbalance carbon cycle

Above-average volcanic activity and significant mountain-building events, increasing rock weathering.

Greenhouse Gases (GHGs)

Carbon dioxide (CO2), Methane (CH4), Nitrous Oxide (N2O), and Water Vapor (H2O).

Greenhouse Effect

A natural phenomenon where GHGs trap heat radiated by Earth, warming the atmosphere.

Positive Feedback

Amplifies the original effect. Example: Melting ice reduces albedo, causing further warming.

Negative Feedback

Reduces the effect. Example: Increased CO2 leads to more plant growth, which removes CO2 from the atmosphere.

Albedo

The reflectivity of a surface. Ice and snow have high albedo, reflecting sunlight. Reduced ice leads to lower albedo and further warming.

Consequences of Climate Change

Rising global temperatures, melting glaciers and ice sheets, sea level rise, ocean acidification, and more frequent extreme weather events.

Evidence of Recent Climate Change

Direct measurements of rising global temperatures, shrinking ice sheets and glaciers, rising sea levels, and increased frequency of extreme weather events.

Keeling Curve

Shows the increase in atmospheric CO2 concentrations since 1958, indicating a sharp rise in CO2 levels, correlating with human activities.

Seasonal Variations in CO2

The natural uptake of CO2 by plants during spring and summer, and release during fall and winter.

Contributors to Sea Level Rise

Melting of land ice (e.g., glaciers, ice sheets) and thermal expansion of seawater due to warming.

CO2 Levels Compared to the Past

Present-day CO2 levels are the highest in the past 400,000 years & are rising at a rate around ten times faster than past natural warming periods.

Milankovitch Cycles

Long-term variations in Earth's orbit and tilt affecting solar radiation received. The three types are eccentricity, obliquity, and precession.

Climate Proxy Indicators

Indirect records of past climate found in ice cores, tree rings, sediment layers, and fossils.

Long-term Climate Change

Climate changes that occur over millions of years, driven by tectonic events and orbital variations.

Short-term Climate Change

Climate changes that occur over decades to centuries, often influenced by volcanic eruptions or solar activity.

Evidence of Anthropogenic Climate Change

CO2 levels correlate with human activities, primarily fossil fuel combustion, and isotope analysis shows a carbon signature from fossil fuels.

Prehistoric Climate Changes

Paleocene-Eocene Thermal Maximum, Cenozoic Cooling, and Younger Dryas.

Eccentricity

Shape of Earth's orbital path (100,000-year cycle)

Obliquity

Angle Earth's axis is tilted (41,000-year cycle)

Precession

Direction Earth's axis of rotation is pointed (23,000-year cycle)