Climate Change and Environmental Proxies

• The course aims to equip students with a fundamental scientific understanding of global warming and climate change.
• The course will build scientific knowledge to address and discuss questions related to global warming and climate change.
• The course focuses on facts, identifying fundamental laws, and modeling to produce approximate answers.

Course Topics

• Weather and Climate
• Large-scale climate change over geological timescales
• Methods of observation
• Current trends in climate
• Natural and human-caused (anthropogenic) climate change.

Basic Science of Global Warming

• Study of thermodynamics principles: temperature, thermal equilibrium, and heat transfer
• Study of radiative heat transfer.
• Blackbody radiation and radiation laws
• Interaction of light with atmospheric gases
• Absorption and the greenhouse effect
• Greenhouse gases.
• The Layer Model
• Radiation balance
• Solar constant and albedo
• Carbon on Earth
• Perturbed Carbon Cycle
• Feedbacks

Impact

• Physical and social impacts of Climate Change: sea level rise, increasing temperatures, droughts and wildfires
• Consideration of global temperature projections

Reduction Options

• Options to reduce Global Warming: renewable energy, carbon capture and storage (CCS), and geo-engineering.

Lecture 2A Topics

• Weather versus Climate
• Variability and Changes
• Global Mean Surface Temperature
• Global warming

Weather vs. Climate

• Both weather and climate relate to atmospheric conditions which are characterized by physical parameters like rainfall, pressure, temperature, humidity, and precipitation.
• These parameters are constantly changing are functions of time.
• Differences between weather and climate are determined by the timescale of averaging.
• Weather reflects atmospheric conditions over short periods
• Climate describes atmospheric conditions over long periods.
• "Short" typically means timescales less than a few months, while "long" refers to several years or more.
• Shorter timescales lead to higher variability and more chaotic behavior, making prediction difficult
• Climate provides a long-term pattern of weather.

Variability

• Both weather and climate have variability.
• 24-hour oscillations related to Earth's rotation.
• 1-year oscillations related to Earth's orbit
• Short-term atmospheric "internal instabilities" (storms, hurricanes).
• The averaging of data can obscure trends, potentially leading to misinterpretations if not analyzed statistically.
• Averaged data can be further processed over intervals of interest: decades, centuries, geological scales
• Over a particular interval, averaged data has a mean and deviations from that mean (variability).
• Variability can be described statistically through a probability distribution function (PDF).
• Smaller deviations from the mean happen more frequently and are more likely.
• Larger deviations are less frequent and less probable.

Variability vs. Change

• If the shape of the PDF stays consistent over time, there are charges over the intervals of interest but there is still variability.
• If the shape of the PDF is changing in time, there are charges over the intervals of interest.

Global Mean Surface Temperature

• Global Warming can be defined using the global mean surface temperature.
• It refers to the surface temperature of both land and ocean.
• It is averaged over Earth over a period of 1-5 years.
• GMST has increased by approximately 0.9 degrees Celsius over the last century.

Global Warming

• Climate is in continual change with major ice ages occurring approximately every 100,000 years.

Measuring Climate Data

• The collection and analysis of climate data have evolved over time, from early thermometer measurements to advanced proxy methods.
• The first meteorological network was formed in northern Italy in 1653.
• Formal international coordination of meteorological observations from ships commenced in 1853
• Scientists use indirect evidence as proxies to determine past climates.
• Proxies are natural datasets that mimic environmental changes.
• Examples of proxies include tree rings, sediment cores, pollen, stable isotopes, ice cores, and coral reefs.

Climate Proxies

Tree Rings

• Tree growth is influenced by climate, which can be observed in tree ring width and isotopic composition.
• Trees generally produce one ring per year.
• Tree ring records can extend back to the last 1000 years.

Sediment Cores

• Sediment cores can be extracted from lakes or oceans.
• The thickness of sediment layers can be used to infer past climates.
• Layers may contain organic material analyzable for climate proxies.

Pollen

• Pollen grains are well-preserved in lake and ocean sediment.
• Analysis of sediment layers provides information on the vegetation.
• Scientists infer past climates based on plant distribution and species changes.

Stable Isotopes

• Oxygen is the most common element used in climate studies.
• Oxygen isotopes include O16 (common), O17, and O18 (rare).
• The ratio of O18 to O16 is affected by temperature.

Coral Reefs

• Corals are composed of calcium carbonate.
• The carbonate contains oxygen isotopes indicative of water temperature.

Ice Cores

• Trapped air bubbles extracted from ice cores provide climate and atmospheric history

This quiz assesses understanding of climate proxies like tree rings, pollen, and ice cores, and their relationship to environmental factors, isotope ratios, and past climates. It also covers the distinction between weather and climate, physical impacts of climate change, and carbon capture strategies, emphasizing the importance of diverse climate proxies.