Jan31PPT

This unit will direct focus on various strategies organisms utilize for essential resource acquisition, particularly energy and water. The unit is structured around three key investigative questions:

1. Climate Change Impacts: Understanding how climate change affects ecosystems and species' responses to these alterations is critical in our study of survival.

2. Resource Acquisition: We will explore the mechanisms by which plants and other organisms obtain carbon and water while balancing necessary trade-offs to thrive in changing environments.

3. Evolution of Strategies: Investigating how evolutionary processes and trade-offs lead to a diversity of survival strategies tailored to various environmental conditions, especially in response to climate change pressures, will be integral to our discussions.

Learning Objectives for the Unit

• Solar Radiation and Greenhouse Gases:

  • Describe the journey of solar radiation after it is absorbed by Earth and explain the critical role greenhouse gases (GHGs) play in this process.

  • Distinguish clearly between climate and weather, reinforcing the importance of this difference in the context of climate studies.

• Detection of Climate Change:

  • Understand the scientific methodologies employed in detecting climatic shifts and changes over time.

  • Define 'proxy data' and provide examples of how it is utilized in climate change studies to infer historical climate conditions.

  • Explain why isolated hot or cold days alone cannot substantiate claims of long-term climate change, emphasizing the need for broader data trends.

• Feedback Loops:

  • Define positive and negative feedback loops, including real-world examples relevant to climate science.

  • Understand the concept of albedo, factors that influence it, and its implications in climate dynamics.

• Forcings Impacting Climate:

  • Distinguish between natural and anthropogenic forces that affect climate, providing specific examples for each category.

  • Predict potential impacts on Earth’s average surface temperature based on changes in greenhouse gas levels and variations in albedo.

• Cloud Cover Conflicts:

  • Explain the role of cloud cover in introducing conflicting feedback mechanisms within climate discussions, including its implications for climate forecasts.

• Ecological Impact of Climate Change:

  • Discuss at least three specific examples of negative ecological impacts attributable to climate change, examining case studies where applicable.

• Temperature Performance Curves:

  • Analyze temperature performance curves to interpret the relationships between temperature fluctuations, population growth, and organismal performance.

  • Recognize the temperature tolerance ranges of species based on performance curve data, detailing how species adapt to day-to-day variability in climate.

Understanding Climate Change

• Definition: Climate change refers to long-term shifts in temperature and weather patterns on Earth due to various influencing factors.

• Key Factors Attributed to Climate Change:

  • Role of GHGs: Investigate how greenhouse gases act as insulators, trapping heat in the atmosphere and causing temperature rises.

  • Natural and Anthropogenic Sources: Explore contributing factors from both natural phenomena (volcanic eruptions, ocean currents) and human activities (fossil fuel burning, deforestation) that lead to climate variations.

  • Feedback Loops: Analyze how feedback mechanisms—as either amplifiers or mitigators—play a critical role in the dynamics of climate change.

Exclusion of Other Atmospheric Phenomena

Not Covered Today:

• Ozone Layer Depletion: Addresses health risks due to higher UV radiation, notably affecting the southern hemisphere.

• Smog & Pollution: Associated with immediate health impacts, though not central to the overarching theme of climate change.

• Acid Rain: Examined in terms of its causes but distinguished by differing effects from those of climate change factors.

Atmospheric Composition Overview

• Composition breakdown:

  • Oxygen: 21.0%

  • Nitrogen: 78.0%

  • Argon: 0.9%

  • Trace Gases: 0.1% (including significant greenhouse gases)

• Influence of GHGs: Despite being a small fraction of the atmosphere, even minimal changes in GHG concentrations can lead to drastic planetary changes in temperatures and weather patterns.

Natural vs. Enhanced Greenhouse Effect

• Natural Greenhouse Effect Basics: The process by which sunlight warmly influences Earth, allowing the atmosphere to remain hospitable for life.

• Human Enhanced Greenhouse Effect: Discuss how increased greenhouse gas emissions due to industrial and domestic practices lead to additional heat retention, resulting in amplified warming effects.

Energy Budget and Greenhouse Effect

• Energy Budget Analysis:

  • Understanding the source and fate of incoming solar energy, noting that 30% is reflected by the atmosphere and clouds, which signifies a substantial energy loss before it reaches Earth’s surface.

  • Highlight the mechanisms of energy absorption that vary by surface types (land, water, vegetation) and their ecological roles in energy retention.

Milankovitch Cycles (Natural Climate Changes)

• Cycles Overview: Discuss long-term natural climate variations that arise from Earth's orbital changes, including:

  • Precession: A cycle of approximately 26,000 years concerning the wobble of Earth’s axis affects climatic patterns over time.

  • Obliquity: Variations in the tilt of Earth’s axis affecting climate cycles roughly every 41,000 years.

  • Eccentricity: Long-term changes in the shape of Earth’s orbit around the Sun, which span about 100,000 years, influencing seasonal solar radiation.

• Total Solar Radiation Impact: Explain how these cycles dictate net solar radiation reaching Earth, referred to as solar forcing, and its implications on climate dynamics.

Adapting to Changes in Greenhouse Effect

• Human Influence on GHGs: Understanding our capacity to manipulate GHG levels and their resulting effects on energy retention in the atmosphere, including key gases:

  • Methane (CH4)

  • Carbon Dioxide (CO2)

  • Nitrous Oxide (N2O)

  • Fluorinated gases

  • Water vapor

GHGs Potency and Impact

• Global Warming Potential (GWP): A metric that measures the relative effectiveness of a greenhouse gas:

  • CO2: GWP of 1

  • CH4: GWP of 21

  • N2O: GWP of 298

  • F-Gases: GWP ranges from 124 to 14,000, depending on the specific gas.

• Anthropogenic Climate Change: The importance of recognizing and addressing the various sources contributing to human-driven climate change, including industrial processes, agriculture, and energy production.