10&11.GlobalClimates&ClimateChange_Web - Copy

Page 1: Overview of Global Climates

• Focus areas this week include:
  • Global PowerPoint Presentation (PPT)
  • Climate Classification
  • Climate Types
  • Global Warming and Climate Change

Page 2: Climate Classification

• Climate Definition: Average weather in a region over a long time.
• Key Climate Components:
  • Insolation
  • Temperature (T)
  • Pressure
  • Air Masses
  • Precipitation (PPT)
• Primary Climate Variables: T and PPT are crucial for describing climate and influence:
  • Vegetation cover
  • Human usage of the area

Page 3: Classification of Climatic Types

• Classification Process: Grouping data into related categories.
  • Genetic Classification: Based on causative factors affecting climate.
  • Empirical Classification: Based on statistical data like temperature and precipitation.

Page 4: Global Precipitation Patterns

• Overview of global precipitation distribution illustrated with a map indicating varying precipitations by latitude.
• Regions categorized by annual precipitation in centimeters:
  • Over 200 cm
  • 150-199 cm
  • 100-149 cm
  • 50-99 cm
  • 25-49 cm
  • Under 25 cm

Page 5: Climate Groups

• 6 Broad Climate Groups subdivided into 13 General Climate Types:
  • Tropical (23.5°N–23.5°S)
  • Mesothermal (midlatitudes, mild winter)
  • Microthermal (cold winters)
  • Polar (high latitudes)
  • Highland (high elevations)
  • Dry (moisture deficits)
• Principal Components Influencing Climate Types:
  1. Insolation
  2. Temperature
  3. Humidity
  4. Seasonal precipitation
  5. Atmospheric pressure & winds
  6. Air masses
  7. Weather disturbances
  8. Cloud coverage

Page 6: World Climate Map

• Visualizations include:
• Global climate maps showing various climates across the world and their characteristics including:
  • Arctic and maritime influences
  • Different climatic regimes leading to diverse vegetation types

Page 7: Climographs

• Climographs:
  • Depict temperature and precipitation patterns over time.
  • Essential for understanding seasonal climate variations including:
  • Extremes of temperature
  • Annual total precipitation.

Page 8: Tropical Climates

• Most extensive climate types covering 36% of the earth’s surface. Key characteristics include:
  • Located between 20°N and 20°S
  • Influences from:
  • Daylength
  • Insolation
  • ITCZ (Intertropical Convergence Zone)
  • 3 Regimes:
  • Tropical Rain Forest: Rainy year-round.
  • Tropical Monsoon: Seasonal rainfall, mostly in summer.
  • Tropical Savanna: Less than 6 months of rainy season.

Page 9: Tropical Rainforest Climate

• Dominated by:
  • Maritime Equatorial (mE) & Maritime Tropical (mT) air masses.
• Characteristics:
  • Uniform temperatures throughout the year.
  • Heavy convectional rainfall (over 250 cm annually).

Page 10: Tropical Monsoon Climate

• Characterized by high annual rainfall but with a strong seasonal variation (mostly summer).
• Affected by the ITCZ, which brings moisture from mT and mE air masses and includes orographic precipitation.

Page 11: Tropical Savanna Climate

• Distinguished by:
  • Very dry winters and very wet summers.
  • Temperature shows high during summer and lower during winter.
• Vegetation known as savanna; grassy plains with scattered trees.

Page 12: Mesothermal Climates

• Cover 55% of the global population and 27% of earth’s surface.
• Key elements include:
  • Air masses
  • Migrating cyclones and anticyclones.
• Four types identified:
  1. Humid subtropical with hot summers
  2. Humid subtropical with dry winters
  3. Marine west-coast
  4. Mediterranean.

Page 13: Humid Subtropical Climate

• Experience either:
  • Moist conditions year-round
  • A pronounced dry winter period.
• Influences from subtropical air from oceans.
• Vegetation predominantly forests.

Page 14: Marine West-Coast Climate

• Characterized by:
  • Influence from prevailing westerlies and mP air masses.
  • High annual precipitation and distinct winter maximum.
• Vegetation consists of dense forests and mosses.

Page 15: Mediterranean Climate

• Very wet winters and very dry summers.
• Influenced by poleward migration of pressure zones.
• Less annual temperature range due to ocean currents.

Page 16: Microthermal Climates

• Occur poleward of mesothermal climates.
• Characterized by:
  • Seasonal temperature changes and cold winters.
• Key Regimes Include:
  • Humid continental hot-summer
  • Humid continental mild-summer
  • Subarctic.

Page 17: Humid Continental Climate

• Experienced in polar-front zones with significant precipitation.
• Very strong annual temperature range and highly variable weather.
• Dominant vegetation includes forests and prairies.

Page 18: Subarctic Climate

• Large annual temperature range, very cold and dry.
• Summer precipitation from mT air masses.
• Dominant vegetation includes boreal forests (taiga).

Page 19: Extreme Subarctic Cold-Winter Climate

• Station data from Verkhoyansk, Russia, (67° 35'N, 133° 27'E) with:
  • Average annual temperature of -15°C
  • Total annual precipitation of 15.5 cm.

Page 20: Polar and Highland Climates

• Cover 19% of the Earth’s surface and 17% of its land area.
• Temperatures characterized by extremes in daylength and low sun altitude.
• 3 Regimes Include:
  1. Tundra Climate
  2. Ice Cap and Ice Sheet Climate
  3. Polar Marine Climate

Page 21: Tundra Climate

• Dominated by polar air masses with long, severe winters.
• Limited annual precipitation.
  - Vegetation mainly consists of grasses, mosses, lichens, and peat bogs; permafrost is common.

Page 22: Ice Cap & Ice Sheet Climate

• Dominated by cold air masses.
• Characterized by bitterly cold temperatures with no monthly average above freezing.
• High altitudes exacerbate cold (altitude effect).

Page 23: Arid & Semi-arid Climates

• Covering 35% of Earth’s land area with unique desert vegetation.
• Four regimes include:
  1. Hot low-latitude desert
  2. Cold midlatitude desert
  3. Hot low-latitude steppe
  4. Cold midlatitude steppe

Page 24: Low Latitude Hot Desert

• Dominated by subtropical high pressure zones.
• Very hot summers with mild winters, large daily temperature ranges.
• Vegetation consists of drought-resistant plants.

Page 25: Midlatitude Cold Desert

• Cover small areas with low T and PPT.
• Characterized by subtropical high pressure influence.

Page 26: Low Latitude Hot Steppe

• Characterized by a short wet season when ITCZ influences the area.
• Very hot summers with mild winters, significant daily temperature ranges.

Page 27: Midlatitude Cold Steppe

• Extends poleward from midlatitude deserts.
• Precipitation more frequent than desert areas due to midlatitude cyclones.

Page 28: Climate Change and Global Warming

• Current global temperature trends impacting climatic and environmental systems.

Page 29: Climate Change Evidence

• Notable changes include:
  • Global warming trends
  • Glacier melting and rising sea levels.
  • Observational data from IPCC (Intergovernmental Panel on Climate Change).

Page 30: Impacts of Global Warming

• Consequences of 1°C increase in temperatures include:
  • Increased weather extremes and rising sea levels.
  • Need for action to limit warming to between 1.5ºC - 2ºC to avoid severe impacts.

Page 31: The Greenhouse Effect

• Physics: Earth absorbs solar shortwave radiation and emits longwave radiation.
• Greenhouse gases trap this radiation, leading to increased temperatures.

Page 32: CO2 Concentration Trends

• Significant rise in atmospheric CO2 observed, indicating long-term trend since the Industrial Revolution.
• Current levels recorded at over 400 ppm.

Page 33: Methods for Understanding Past Climates

• Proxy Data: Techniques yielding long-term climate records from ice cores and ocean sediments.
• Isotope Analysis: Used to reveal past chemical compositions in oceans/ice.

Page 34: Proxy Data Visualization

• Depicting significant paleoclimatic data with impressions from snowpits and ice cores revealing atmospheric conditions.

Page 35: Short-Term Climate Reconstruction

• Tools include:
  • Radiocarbon dating
  • Growth ring analysis of trees, corals, and speleothems.

Page 36: Proxy Data Implications

• Variations in oxygen isotopes indicate past climate changes, revealing periods of warmer and cooler temperatures.

Page 37: Recent Climate History

• Historical temperature shifts documented, showing significant fluctuations over thousands of years.

Page 38: Natural Climate Fluctuations

• Influencing factors include:
  • Solar variability
  • Earth’s orbital cycles
  • Continental position and atmospheric gases.

Page 39: Climate Feedbacks and Carbon Budget

• Climate feedbacks amplify or reduce warming.
• Earth’s Carbon Budget: Elements like water vapor and CO2 that influence climate.

Page 40: Present Climate Change Evidence

• Indicators of change include:
  • Rising temperatures
  • Melting ice
  • Increasing extreme weather events.

Page 41: Human Impact on Climate

• Key factors in global warming include:
  • Increased greenhouse gas concentrations (CO2, CH4, N2O).

Page 42: Sources of Radiative Forcing

• Different sources explaining radiative forcing impacts categorized into:
  • Natural
  • Anthropogenic factors.

Page 43: Climate Models and Forecasts

• General circulation models (GCMs) used for past trends and future forecasts in climate changes.

Page 44: Climate Forcing Effects

• Tracking temperature changes due to both natural and anthropogenic forcing.

Page 45: AOGCM Scenarios for Surface Warming

• Models predicting variations in global warming under different emission scenarios.

Page 46: Actions Against Climate Change

• Discussion on potential actions individuals can take and references for further reading on climate science.