Introduction to Climate Change

Foundations of Climate Science: Weather vs. Climate

  • Definition of Weather:

    • Refers to specific atmospheric conditions and localized events occurring over short durations (ranging from a few hours to days or weeks).

    • Exhibits continuous fluctuation on minute-to-minute, hour-to-hour, day-to-day, and season-to-season timescales.

    • Key atmospheric variables measured include temperature, precipitation, humidity, cloudiness, brightness, atmospheric visibility, wind speed/direction, and barometric atmospheric pressure.

  • Definition of Climate:

    • Refers to the long-term statistical average of weather patterns observed in a specific geographical region measured over a period of 30 years30\text{ years} or longer.

    • Analyzes structural parameters including average precipitation, temperature trends, relative humidity, total sunshine duration, wind velocity, and frequencies of meteorological events such as fog, frost, and hail storms.

  • Conceptual Distinction:

    • An intuitive rule of thumb: "Climate is what you expect, weather is what you get."

    • Example: Climate represents expecting a very hot summer overall, whereas weather represents receiving a single hot day accompanied by pop-up thunderstorms.

The Greenhouse Effect and Human Activity

  • Natural Greenhouse Effect:

    • A natural planetary process in which greenhouse gases in Earth's atmosphere absorb and re-emit thermal infrared radiation back toward the planetary surface.

    • Traps heat near the surface, elevating global temperatures to a level capable of sustaining biological life.

    • Primary naturally occurring greenhouse gases include:

      • Carbon Dioxide (CO2CO_2)

      • Methane (CH4CH_4)

      • Nitrous Oxides (N2ON_2O)

      • Water Vapour (H2OH_2O)

  • Anthropogenic Climate Change:

    • Refers to persistent, long-term shifts in atmospheric temperatures and global weather patterns.

    • While natural climate variability exists, human activity starting during the Industrial Revolution (circa the 1800s) has served as the primary driver of modern climate change through the combustion of fossil fuels (coal, oil, and natural gas).

    • Fossil fuel burning releases substantial quantities of CO2CO_2 and CH4CH_4, artificially amplifying the natural greenhouse effect.

  • Primary Drivers of Anthropogenic Greenhouse Gas Emissions:

    • Generating electricity and heat via fossil fuel combustion.

    • Manufacturing goods and industrial processing, specifically cement, iron, steel, electronics, plastics, and synthetic or natural textiles/clothing.

    • Mining and mineral extraction operations.

    • Deforestation and clear-cutting land to construct farms, pastures, or industrial sites.

    • Transportation infrastructure, as the vast majority of automobiles, trucks, commercial ships, and aircraft rely on petroleum-based fuels.

    • Agricultural operations, including food production, commercial processing, and packaging.

Global Temperature Trends and Regional Benchmark Observations

  • Global Temperature Baselines:

    • The Earth's global mean surface temperature is currently approximately 1.1^\text{ }^\text{o}\text{C} warmer than late-1800s pre-industrial averages.

    • The decade spanning 2011–2020 was officially designated as the warmest decade in recorded human history.

    • Earth acts as an integrated system; temperature alterations in one domain cascade across all linked ecological and physical systems.

  • Global Meteorological Data Snapshot (March 2021 Records):

    • Global Land and Ocean Temperature: March 2021 ranked as the 8th highest global average surface temperature for the month of March since comprehensive record-keeping began in 1880.

    • Global Temperature Anomaly: Annual mean tracking showed a historical anomaly reaching +0.51^\text{ }^\text{o}\text{C} relative to historical reference baselines.

    • Arctic Sea Ice Extent: Measured at 5.1%5.1\text{\%} below the 1981–2010 historical baseline average, making it the 9th smallest March extent since satellite observation began in 1979. Reached its annual maximum extent on March 21, 2021 (tying with 2007 as the 7th smallest annual maximum in the 43-year satellite tracking record).

    • Antarctic Sea Ice Extent: Measured at 10.4%10.4\text{\%} above average, ranking as the 10th largest March extent on record.

    • North America: Recorded its highest March temperature departure since 2016 and the 10th highest March temperature in recorded history.

    • Contiguous United States: Placed within the warmest third of its 127-year historical weather record.

    • Africa: Recorded its 11th warmest March in recorded history.

    • South America: Recorded its 16th warmest March in recorded history.

    • Asia: Recorded its 9th warmest March in recorded history.

    • Cyclone Niran: Formed in the South Pacific Ocean as the second Category 5 cyclone recorded in 2021. Caused structural damage across New Caledonia despite its core remaining offshore.

Comprehensive Effects of Climate Change

  • Hotter Temperatures:

    • Each sequential decade is warmer than the preceding one.

    • Nearly all land masses are experiencing an increase in the number of hot days and high-intensity heat waves.

  • Severe Storm Systems:

    • Thermal energy accumulation leads to an increase in both storm intensity and global storm frequency.

  • Severe Drought and Aridity:

    • Desert biomes are expanding, directly contracting the availability of arable agricultural land.

    • Increases global populations experiencing chronic, regular water shortages.

  • Ocean Thermal Shifts:

    • The rate of ocean warming has accelerated over the past two decades.

    • Drives severe disruption to marine life, coral bleaching, and structural breakdown of reef systems.

  • Biodiversity Loss:

    • Global species extinction is occurring at a rate 1,000 times1,000\text{ times} greater than at any point in recorded human history.

  • Human Health and Welfare Risks:

    • Degraded air quality and expanded ranges for disease vectors.

    • Increased frequency of severe weather events causing forced human displacement.

    • Psychological stress and worsening mental health outcomes.

    • Nutritional deficits and widespread hunger driven by crop failures in regions unable to cultivate sufficient food.

  • Poverty and Forced Migration:

    • Weather-related disasters displaced an estimated 21.3%21.3\text{\%} of vulnerable affected populations on average each year over the past decade.

Climate Change in Canada and Global Emissions Responsibility

  • Global Distribution of Carbon Emissions:

    • The 100 least-emitting nations combined generate only 3%3\text{\%} of total global greenhouse gas emissions.

    • The 10 largest emitting nations generate 68%68\text{\%} of all global greenhouse gas emissions.

    • Canada ranks as the 9th worst emitting nation among the top 10 worst global polluters.

  • Canadian Climate Trends:

    • Canada's environment is deteriorating significantly faster than global averages.

    • The rate of climate warming in Canada is double (2×2\times) the global rate.

  • Corporate Concentration and Systemic Policy Challenges:

    • The industrial operations of just 100 corporations produce 71%71\text{\%} of total global greenhouse gas emissions.

    • Numerous global governments have failed to pass enforceable climate policies or regulations.

    • Institutional power and wealth remain tied to status-quo energy models.

    • While global action is required across all nations, high-emitting countries and major industrial actors bear proportional responsibility to implement climate solutions first.

The Köppen-Geiger Climate Classification System

  • System Architecture:

    • The Köppen-Geiger climate classification system divides Earth's terrestrial climates into five main climate groups based on global patterns of seasonal precipitation and surface temperature.

  • The Five Primary Climate Groups:

    1. Group A: Tropical

    2. Group B: Arid / Desert

    3. Group C: Temperate

    4. Group D: Continental

    5. Group E: Polar

  • Subgroup Classifications:

    • All primary groups except Group E are assigned a second letter denoting seasonal precipitation characteristics.

    • Example: The classification code "Af" indicates a tropical rainforest climate characterized by persistent precipitation.

  • Canadian Climate Zone Distribution:

    • Canada contains climate subzones belonging to Main Groups B, C, D, and E.

  • Detailed Köppen-Geiger Subzone Classifications:

    • BSk: Cold Semi-Arid

    • BWk: Cold Desert

    • Csb: Warm Summer Mediterranean

    • Cfb: Temperate Oceanic

    • Dsb: Humid Continental (mild summer)

    • Dsc: Continental Subarctic

    • Dwb: Humid Continental (mild summer)

    • Dwc: Subarctic (cool summer)

    • Dfa: Humid Continental (hot summer) — This zone includes the specific local climate of Toronto

    • Dfb: Humid Continental (mild summer)

    • Dfc: Subarctic (cool summer)

    • ET: Tundra

The Intergovernmental Panel on Climate Change (IPCC)

  • Establishment and Mandate:

    • Established in 1988 under the joint auspices of the United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO).

    • Tasked with evaluating human-caused (anthropogenic) climate change risks and synthesizing scientific research for policy consideration.

  • Historical Recognition:

    • In 2007, the IPCC and Albert (Al) Gore were jointly awarded the Nobel Peace Prize.

    • Citation: Awarded "for their efforts to build up and disseminate greater knowledge about man-made climate change, and to lay the foundations for the measures that are needed to counteract such change."

Sea Level Elevation, Rising Oceans, and Coastal Vulnerability

  • Sea Level as a Global Datum:

    • Because Earth's oceans form a continuous interconnected body of liquid water, sea level serves as the standardized baseline for measuring geographic elevation (going upward) and ocean depth (going downward).

  • Elevation Reference Examples:

    • Commercial airliners operate at cruise altitudes between 9,400 m9,400\text{ m} and 11,600 m11,600\text{ m} above sea level.

    • The city of Toronto sits at approximately 76.5 m76.5\text{ m} above sea level along the Lake Ontario shoreline and reaches 209 m209\text{ m} above sea level near York University.

  • Mechanisms of Sea Level Rise:

    • Melting Glaciers and Ice Sheets: Transfers land-stored ice mass directly into ocean water volume.

    • Ocean Thermal Expansion: As seawater absorbs atmospheric heat energy, its molecular volume expands.

  • Geographic Risk Exposure:

    • Regions located directly at current sea level face heightened risks of extreme coastal flooding.

    • Highly vulnerable entities include Tuvalu, the Federated States of Micronesia, Bangladesh, the Netherlands, and the State of Florida.

Agricultural Impacts and Environmental Shifts

  • Precipitation Extremes and Crop Vulnerability:

    • Arid Regions (e.g., Sub-Saharan Africa): Suffer decreased water access leading to severe droughts, reduced agricultural yields, livestock collapse, and regional famine.

    • Wet Regions (e.g., Southern United States and Japan): Suffer increased rainfall intensity leading to crop damage, soil erosion, and agricultural runoff.

  • Agronomic Shifts:

    • Lengthening growing seasons may provide yield benefits for specific warm-weather crops, such as soybeans and corn.

    • Warming conditions permit crop varieties to be cultivated in northern regions where they could not historically survive (e.g., expanded agricultural options in Southern Ontario).

    • Negative operational trade-offs include accelerated growth of invasive weeds, agricultural pests, and crop pathogens.

Ecosystem Disruption, Biodiversity Loss, and Northward Ecoregion Migration

  • Ecosystem Poleward Shift:

    • As regional temperature baselines become inhospitable, native plant and animal species are forced to migrate poleward (northward in the Northern Hemisphere).

    • Displaces established ecosystems, leading to habitat fragmentation and broad loss of biodiversity.

    • Biodiversity loss undermines food webs, trophic chains, and critical ecological resources.

  • Biological Invasions and Vector Spreading:

    • Northward ecological migration facilitates the entry of non-native invasive species into unadapted ecosystems.

    • Drives the geographic expansion of human and agricultural health hazards, including malaria-carrying mosquito vectors and crop-destroying pests.

  • Canadian Ecoregion Projections (Present Day vs. Doubled Atmospheric CO2CO_2 by Year 2060):

    • Under a doubled atmospheric carbon dioxide scenario (projected around the year 2060), Canada's ecological landscape undergoes a massive northward shift:

      • Tundra and Boreal forest biomes contract significantly toward polar latitudes.

      • Temperate, Grassland, and Semi-Arid biomes expand substantially northward into regions currently designated as Boreal ecosystems.


Map of Canada comparing present day ecoregions to projected ecoregion shifts under doubled CO2 by 2060


The Köppen-Geiger Climate Classification System

  • System Architecture:
    • Divides Earth's terrestrial climates into five primary climate groups based on global patterns of seasonal precipitation and surface temperature.
  • The Five Primary Climate Groups:
    1. Group A: Tropical
    2. Group B: Arid / Desert
    3. Group C: Temperate
    4. Group D: Continental
    5. Group E: Polar
  • Subgroup Classifications:
    • All primary groups except Group E are assigned a second letter denoting seasonal precipitation characteristics.
    • Example: The classification code "Af" indicates a tropical rainforest climate characterized by persistent precipitation.
  • Canadian Climate Zone Distribution:
    • Canada contains climate subzones belonging to Main Groups B, C, D, and E.
  • Detailed Subzone Classifications:
    • BSk: Cold Semi-Arid
    • BWk: Cold Desert
    • Csb: Warm Summer Mediterranean
    • Cfb: Temperate Oceanic
    • Dsb: Humid Continental (mild summer)
    • Dsc: Continental Subarctic
    • Dwb: Humid Continental (mild summer)
    • Dwc: Subarctic (cool summer)
    • Dfa: Humid Continental (hot summer) — includes local climate of Toronto
    • Dfb: Humid Continental (mild summer)
    • Dfc: Subarctic (cool summer)
    • ET: Tundra

The Intergovernmental Panel on Climate Change (IPCC)

  • Establishment and Mandate:
    • Established in 19881988 under joint auspices of UNEP (United Nations Environment Programme) and WMO (World Meteorological Organization).
    • Tasked with evaluating anthropogenic climate change risks and synthesizing scientific research for policy consideration.
  • Historical Recognition:
    • In 20072007, the IPCC and