IOF Forestry Climate Change Fundamental Concept by Rabindra

IOF Forestry Climate Change Fundamental Concept by Rabindra

1. Unit 1 : Climate Change Fundamental Concept

2. Contents UNIT 1: CLIMATE CHANGE FUNDAMENTAL CONCEPT [6] 1.1 Understand the basics of weather, climate 1.2 Understand and describe the most important processes involved in climate change, and the interactions between the atmosphere, ocean and land surface 1.3 Basic concepts involved in the economic control of climate change 1.4 Different possible environmental ethics positions with regards to climate change 1.5 Concept of Climate Models

3. Weather and Climate Weather Weather refers to the short-term atmospheric conditions in a specific area at a particular time. It includes changes that occur over minutes, hours, or days. Weather is what we experience daily, such as sunshine, rain, snow, or wind.

4. Components of Weather Temperature : Measures how hot or cold the atmosphere is. Precipitation : Any form of water, liquid or solid, that falls from the atmosphere (e.g., rain, snow, hail). Humidity : The amount of water vapor in the air. Wind : The movement of air caused by differences in atmospheric pressure. Atmospheric Pressure : The force exerted by the weight of the air above a specific point. Cloud Cover : The fraction of the sky covered by clouds.

5. Climate Climate refers to the long-term patterns and averages of weather in a particular region over decades, centuries, or even millennia. It provides a broader picture of atmospheric conditions and is used to predict general trends.

6. Components of Climate Average Temperature : The mean temperature over a long period. Average annual temperature trend of Nepal (1987-2016). Source: World Bank Group (2020).

7. Components of Climate 2. Precipitation Patterns : The average rainfall, snowfall, and other forms of precipitation over time.

8. Components of Climate 3. Seasonal Variations : Changes in weather patterns across seasons. Study area and spatial distribution of mean precipitation over GRB obtained from 28 meteorological stations. The monthly cycle of ( b ) average precipitation and ( c ) temperature over GRB during 1985–2014.

9. Components of Climate 4. Extreme Weather Events : Frequency and intensity of events like droughts, or heatwaves. 5. Atmospheric Circulation : Large-scale wind patterns that influence regional climates.

10. S/N Weather Climate 1 Weather is the condition of the atmosphere in a specific place at a given point in time; these atmospheric conditions may take place day by day, minute by minute, or seasonally. Climate is the average weather conditions over a place, and it mostly takes place after 30 years of time. 2 Weather may involve just one condition of the atmosphere. Climate includes all the conditions of the atmosphere, such as temperature, precipitation, wind, humidity, cloud, and pressure. 3 Weather occurs in a place within a short period. Climate takes place over a long period of time. 4 Weather is what you get on a daily basis. Climate is what you expect over a long time. 5 Weather changes within a short time. The overall changes and variations of a climate are very stable and may take decades or centuries to occur. 6 The scientific study of weather is called meteorology, and a meteorologist studies weather. The scientific study of climate is called climatology; a climatologist studies climate.

11. Factors Influencing Weather Local Geography : Proximity to oceans, mountains, or urban areas. Air Masses : Large bodies of air with similar temperature and humidity. Fronts : Boundaries between different air masses. Solar Radiation : Daily changes in sunlight.

12. Factors Influencing Climate Latitude : Distance from the equator affects temperature and sunlight. Altitude : Higher altitudes generally have cooler climates. Ocean Currents : Warm or cold currents influence regional climates. Global Wind Patterns : Trade winds, westerlies, and polar easterlies. Human Activities : Deforestation, urbanization, and greenhouse gas emissions.

13. Processes involved in Climate Change The Greenhouse Effect The greenhouse effect is a natural process essential for life on Earth. Without it, our planet would be approximately 33°C colder. However, human activities have significantly enhanced this effect, leading to warming. Natural Greenhouse Effect: Incoming solar radiation passes through the atmosphere and warms Earth's surface. The surface then emits infrared radiation, which greenhouse gases (GHGs) in the atmosphere partially absorb and re-emit in all directions. This process maintains Earth's average temperature at about 15°C instead of -18°C.

14. Processes involved in Climate Change The Greenhouse Effect Since the Industrial Revolution, human activities have increased atmospheric GHG concentrations dramatically: Carbon dioxide (CO2): From 280 ppm to over 410 ppm Methane (CH4): More than doubled Nitrous oxide (N2O): Increased by about 20% Primary sources of enhanced GHGs include: Fossil fuel combustion (power generation, transportation, industry) Deforestation and land-use changes Industrial processes (cement production, chemical manufacturing) Agricultural practices (rice cultivation, livestock farming) Waste management systems

15. Carbon Cycle The carbon cycle involves both rapid (biological) and slow (geological) processes that move carbon between different reservoirs: Biological Carbon Cycle: Photosynthesis removes approximately 120 Gt of carbon annually from the atmosphere Respiration and decomposition return similar amounts This cycle maintained relative stability for thousands of years Geological Carbon Cycle: Weathering of rocks Volcanic emissions Formation and burial of organic sediments Operating on timescales of millions of years

16. Carbon Cycle Anthropogenic Disruption to Natural Carbon Cycle: Human activities now add about 9 Gt of carbon annually to the atmosphere, overwhelming natural removal processes. This excess has several consequences: Increased atmospheric CO2 concentration Ocean acidification as seas absorb excess CO2 Changes in terrestrial carbon storage

17. Climate Feedback Mechanisms Understanding feedback loops is crucial for understanding why climate change doesn't proceed linearly. These mechanisms can either amplify (positive feedback) or dampen (negative feedback) initial changes. Key Positive Feedbacks: Ice-Albedo Feedback: Initial warming melts ice and snow Darker surfaces exposed More solar radiation absorbed Further warming occurs Process continues in a cycle

18. Climate Feedback Mechanisms Water Vapor Feedback: Warming increases atmospheric water vapor capacity Water vapor is a greenhouse gas More warming occurs Creates a powerful amplification effect

19. Climate Feedback Mechanisms Permafrost Feedback: Warming thaws permafrost Frozen organic matter decomposes Releases CO 2 and CH 4 Increases greenhouse effect Leads to more warming

20. Ocean Processes and Climate Change Oceans play a crucial role in climate regulation through several mechanisms: Heat Absorption and Distribution: Oceans absorb about 93% of excess heat from greenhouse warming Global circulation patterns distribute this heat Thermal expansion contributes to sea level rise

21. Ocean Processes and Climate Change Chemical Changes: Oceans absorb approximately 25% of anthropogenic CO2 Forms carbonic acid (H2CO3) Decreases pH (ocean acidification) Affects marine ecosystems, particularly calcifying organisms Circulation Changes: Warming affects thermohaline circulation Could potentially disrupt major current systems May lead to regional climate variations

22. Atmospheric Circulation and Weather Patterns Climate change affects atmospheric circulation in several ways: Jet Stream Modifications: Reduced temperature gradient between poles and equator A slower jet stream tends to develop larger waves (Rossby waves), creating a wavier, more irregular path (Meandering). Increased probability of persistent weather conditions

23. Atmospheric Circulation and Weather Patterns Climate change affects atmospheric circulation in several ways: Hadley Cell Expansion: Tropical circulation extends poleward Affects precipitation patterns Contributes to desert expansion Storm Systems: Warmer oceans provide more energy for storms Higher atmospheric moisture content Potentially more intense precipitation events

24. Interaction between Atmosphere, Ocean and Land surface 1. The Atmosphere The atmosphere is the layer of gases surrounding the Earth. It plays a critical role in regulating the planet's temperature and climate. Key Components: Greenhouse Gases (GHGs):  Carbon dioxide (CO₂), methane (CH₄), and water vapor trap heat, creating the greenhouse effect. Solar Radiation:  The atmosphere absorbs, reflects, and scatters incoming solar radiation. Weather Systems:  Atmospheric circulation patterns influence global climate. Interactions: With Oceans:  The atmosphere exchanges heat, moisture, and gases (e.g., CO₂) with the oceans, influencing ocean currents and weather patterns. With Land Surface:  The atmosphere interacts with the land through processes like evaporation, transpiration, and precipitation, affecting soil moisture and vegetation growth.

25. Interaction between Atmosphere, Ocean and Land surface 2. The Oceans The oceans cover about 71% of the Earth's surface and are a major component of the climate system. Key Components: Ocean Currents:  Driven by wind, temperature, and salinity differences, currents redistribute heat globally (e.g., Gulf Stream). Thermohaline Circulation:  A global conveyor belt of deep ocean currents driven by density differences. Heat Capacity:  Oceans absorb and store large amounts of heat, moderating global temperatures. Interactions: With Atmosphere:  Oceans absorb CO₂ from the atmosphere, reducing greenhouse gas concentrations but leading to ocean acidification. They also release heat and moisture, influencing atmospheric circulation. With Land Surface:  Coastal areas are directly affected by sea level rise and storm surges. Ocean temperatures also influence rainfall patterns over land.

26. Interaction between Atmosphere, Ocean and Land surface 3. The Land Surface The land surface includes soil, vegetation, and human-made structures. It plays a vital role in the climate system through its physical and biological processes. Key Components: Forests:  Act as carbon sinks, absorbing CO₂ from the atmosphere through photosynthesis. Soil:  Stores carbon and water, influencing local and global climate. Albedo:  The reflectivity of the land surface affects how much solar energy is absorbed or reflected. Interactions: With Atmosphere:  Forests release water vapor through transpiration, contributing to cloud formation and precipitation. Deforestation increases CO₂ levels and reduces evapotranspiration, altering local and global climate. With Oceans:  River runoff from land carries nutrients and sediments into oceans, affecting marine ecosystems. Land-use changes can also influence coastal erosion and sea level rise.

27. The interactions between the atmosphere, oceans, and land surface are dynamic and interconnected. Examples: El Niño-Southern Oscillation (ENSO):  A periodic warming (El Niño) or cooling (La Niña) of the Pacific Ocean affects global weather patterns, leading to droughts, floods, and changes in forest productivity. Carbon Cycle:  CO₂ is exchanged between the atmosphere, oceans, and land. Forests act as carbon sinks, but deforestation releases stored carbon, exacerbating climate change. Hydrological Cycle:  Water moves between the atmosphere, oceans, and land through evaporation, condensation, and precipitation. Forests play a key role in regulating this cycle.

28. ENSO warm and cold phases and observational record.  a  Examples of strong El Niño (top) and La Niña (bottom) events seen in the tropical Pacific surface temperature (SST) distribution, with characteristic strong and weak SST gradient along the equator, respectively.  b  ENSO record since the 1980s. Note the three extreme events of the past four decades (1982, 1997 and 2015) and the weakening of ENSO variability between years 2000 and 2015. Temperature is averaged for the NINO3 region (5ºC-5ºN, 150ºW-90ºW) in the eastern equatorial Pacific. Based on NOAA Extended Reconstructed SST V5 data ( Huang et al., 2017 ).

29. Schematic view of the components of the global climate system (bold), their processes and interactions (thin arrows) and some aspects that may change (bold arrows). Source: IPCC Third Assessment Report, Working Group 1, The Scientific Basis.

30. Economic Control of Climate Change Economics of Climate Change Market Failure and Externalities At the heart of climate change economics lies the concept of market failure through negative externalities. When companies or individuals emit greenhouse gases (GHGs), they don't bear the full social cost of their actions. Instead, these costs are "externalized" to society at large and future generations. This creates a classic market failure where: The private cost of emissions is lower than the social cost Markets fail to efficiently allocate resources There is no natural market mechanism to correct the problem The gap between private and social costs leads to excessive emissions, as emitters don't factor in the damage their actions cause to others.

31. Economic Control of Climate Change Social Cost of Carbon (SCC) It includes: Agricultural impacts Human health effects Property damage from increased flood risk Ecosystem services disruption

32. Economic Control of Climate Change Economic Control Mechanisms Carbon Pricing Carbon pricing is the primary economic tool for controlling climate change. It works by making emitters pay for their GHG emissions, thereby internalizing the externality. The two main approaches are: Carbon Taxes Direct price on carbon emissions Provides price certainty but quantity uncertainty Easier to implement and administer More predictable for businesses Revenue can fund climate initiatives or reduce other taxes

33. Carbon Taxes: Canada: Introduced in 2008 at C$10/ tonne , gradually increasing to C$50/ tonne by 2022. It's revenue-neutral, meaning proceeds are returned to citizens through tax cuts and rebates. Studies show it reduced emissions by 5-15% while having minimal economic impact. Sweden: Has the highest carbon tax globally at €114/ tonne . Implemented in 1991, it has helped Sweden reduce emissions by 25% while its economy grew significantly. Heavy industry initially received exemptions that were gradually phased out. France: Attempted to introduce a carbon tax in 2018, starting at €44/ tonne with planned increases. However, this sparked the "Yellow Vests" protests due to concerns about fuel costs,

34. Economic Control of Climate Change Economic Control Mechanisms Carbon Pricing 2. Cap-and-Trade Systems Sets total emission limit and allows trading of permits Provides quantity certainty but price uncertainty More complex to implement Market-based price discovery Can link different authorities

35. Economic Control of Climate Change Economic Control Mechanisms Cap-and-Trade Systems (Examples) European Union Emissions Trading System (EU ETS) Region : European Union Launch : 2005 Overview : The EU ETS is the largest and oldest cap-and-trade system in the world. It covers more than 11,000 power stations and industrial plants across the EU, as well as airlines operating within the region. How it works : The EU sets an overall cap on emissions for each year, which decreases over time. Companies receive or buy emission allowances, and if they emit less than their allowance, they can sell the surplus. If they exceed their allowance, they must buy additional permits or face fines. Impact : The EU ETS has been successful in reducing emissions from the power sector and heavy industry, although it faced challenges in its early years due to an oversupply of permits, which led to low carbon prices. Reforms have since strengthened the system.

36. Economic Control of Climate Change Economic Control Mechanisms Cap-and-Trade Systems (Examples) California Cap-and-Trade Program Region : California, USA Launch : 2013 Overview : California's cap-and-trade program is part of the state's broader efforts to reduce greenhouse gas emissions under its Global Warming Solutions Act (AB 32). It covers about 85% of the state’s emissions, including electricity generation, transportation fuels, and industrial sources. How it works : The program sets a cap on emissions that declines annually. Companies receive allowances through auctions or free allocations, and they can trade these allowances on the market. California also links its system with Quebec’s cap-and-trade program, allowing for cross-border trading. Impact : The program has helped California reduce emissions while maintaining economic growth. Revenue from the auctions is used to fund clean energy projects, public transportation, and other climate initiatives.

37. Economic Control of Climate Change Economic Control Mechanisms Cap-and-Trade Systems (Examples) China National Emissions Trading System (ETS) Region : China Launch : 2021 (pilot programs began in 2013) Overview : China launched its national ETS in 2021, making it the largest carbon market in the world by volume of emissions covered. Initially, the system focuses on the power sector, covering over 2,000 power plants responsible for about 40% of China’s total emissions. How it works : The Chinese ETS sets a cap on emissions for power plants based on their output and efficiency. Companies receive free allowances based on their historical emissions and production levels. If they emit less than their allowance, they can sell the surplus; if they exceed it, they must buy additional permits. Impact : While still in its early stages, the Chinese ETS has the potential to significantly reduce emissions from the power sector. However, critics argue that the initial caps are relatively lenient, and the system may need further tightening to drive more reductions.

38. Economic Control of Climate Change Economic Control Mechanisms Cap-and-Trade Systems (Examples) South Korea Emissions Trading Scheme (K-ETS) Region : South Korea Launch : 2015 Overview : South Korea’s ETS is the first nationwide carbon market in East Asia. It covers about 68% of the country’s total emissions, including industries such as power generation, steel, cement, petrochemicals, and aviation. How it works : The government sets a cap on emissions for covered sectors, and companies receive allowances through a combination of free allocation and auctions. Companies that reduce emissions below their allowance can sell their excess permits, while those that exceed their limit must purchase additional allowances. Impact : The K-ETS has contributed to modest emissions reductions, but like many new systems, it has faced challenges, including concerns about the stringency of the cap and the allocation of free permits.

39. Economic Control of Climate Change Complementary Economic Measures While carbon pricing is central, other economic instruments play important roles: Subsidies and Incentives Renewable energy feed-in tariffs Tax credits for clean technology Research and development funding Reforestation incentives Energy efficiency grants

40. Economic Control of Climate Change Complementary Economic Measures Regulatory Standards Minimum energy efficiency requirements Renewable portfolio standards Vehicle emission standards Building codes Forest conservation requirements

41. Different possible environmental ethics positions with regard to climate change Environmental ethics is the branch of philosophy that examines human responsibilities towards the environment. Climate change presents ethical challenges, as it affects current and future generations, non-human species, and ecosystems.

42. Environmental ethics 1. Anthropocentric Ethics (Human-Centered Approach) Anthropocentrism views humans as the central concern of ethics, valuing nature mainly for its usefulness to people. Climate change is a problem because it threatens human well-being, economic stability, and survival. Policy Implications : Climate action is justified if it benefits human societies. Economic growth and development should be balanced with climate policies. Technological solutions (geoengineering, carbon capture) are preferred over drastic lifestyle changes. Criticism : Ignores the intrinsic value of nature and prioritizes human interests over ecological health.

43. Environmental ethics 2. Biocentric Ethics (Life-Centered Approach) Biocentrism extends moral consideration to all living beings, not just humans. Climate change is an ethical issue because it threatens all forms of life, not just humans. Policy Implications : Policies should protect biodiversity and ecosystems. Deforestation, habitat destruction, and pollution are unethical. Humans should adopt sustainable lifestyles that minimize harm to other species. Criticism : May conflict with human development needs and economic priorities.

44. Environmental ethics 3. Ecocentric Ethics (Ecosystem-Centered Approach) Ecocentrism values entire ecosystems, not just individual species or humans. It views nature as having intrinsic worth, independent of human needs. Climate change disrupts ecological balance and is therefore morally unacceptable. Policy Implications : Strong support for conservation, reforestation, and ecosystem restoration. Calls for reduced reliance on fossil fuels and large-scale industrial activities. Advocates for lifestyle changes such as reduced consumption and minimal ecological footprint. Criticism : May limit economic and technological development.

45. Environmental ethics 4. Deep Ecology A radical form of ecocentrism, deep ecology emphasizes a deep spiritual and philosophical connection between humans and nature. Climate change is a result of human arrogance and overconsumption. Policy Implications : Advocates for drastic population reduction and simple, eco-friendly living. Opposes consumerism and industrialization. Encourages ecological activism and grassroots movements. Criticism : Seen as extreme and impractical in modern society.

46. Environmental ethics 5. Social Ecology Links environmental problems like climate change to social injustices, capitalism, and power imbalances. Climate change is caused by political and economic systems that exploit both nature and marginalized communities. Policy Implications : Advocates for systemic change, such as shifting to eco-socialist economies. Calls for environmental justice, ensuring poor communities are not disproportionately affected. Supports policies that address both social inequality and environmental protection. Criticism : Focuses more on social structures rather than individual responsibility.

47. Environmental ethics 6. Theocentric Ethics (Religion-Based Approach) Views nature as sacred, created by a divine being, and emphasizes human responsibility as stewards of the Earth. Humans have a moral duty to protect the environment as part of religious and ethical responsibility. Policy Implications : Religious institutions advocate for sustainability and climate action. Encourages ethical consumerism, conservation, and respect for nature. Many faith-based organizations promote climate justice. Criticism : Relies on religious beliefs, which may not be universally accepted.

48. Environmental ethics 7. Ecofeminism Links environmental issues with gender equality, arguing that the exploitation of nature is connected to the oppression of women. Climate change disproportionately affects women, particularly in developing countries. Policy Implications : Calls for the empowerment of women in climate decision-making. Supports sustainable agriculture and community-based conservation. Criticizes corporate and patriarchal structures that harm the environment. Criticism : Some argue it overemphasizes gender while discussing environmental issues.

49. Climate Models Climate models are mathematical tools used to simulate the Earth’s climate system. They help scientists understand past, present, and future climate conditions by representing the complex interactions between various components of the Earth system, such as the atmosphere, oceans, land surface, ice sheets, and biosphere. Climate models are computer-based simulations that use equations derived from physical, chemical, and biological principles to represent processes in the Earth’s climate system. These models operate on a grid system, dividing the Earth into three-dimensional cells to calculate changes in temperature, precipitation, wind patterns, and other variables over time.

50. Why do we need Climate Models ? To create an understanding of the climate processes. To create reasonable-scenarios, reflecting the current state of scientific understanding. To plan for the future. “a simplified description, esp. a mathematical one, of a system or process, to assist calculations and predictions”

51. Components of Climate Models Atmospheric Models : Simulate the behavior of the atmosphere, including air circulation, cloud formation, and greenhouse gas concentrations. Oceanic Models : Represent ocean currents, heat storage, and carbon uptake. Land Surface Models : Focus on vegetation, soil moisture, snow cover, and interactions between the land and atmosphere. Cryosphere Models : Study ice sheets, glaciers, and permafrost dynamics. Biosphere Models : Include ecosystems like forests, grasslands, and wetlands, which play a role in carbon cycling and energy exchange.

52. Types of Climate Models Energy Balance Models (EBMs) : Energy Balance Models represent the simplest class of climate models, focusing on the fundamental principle of energy conservation in the Earth's climate system. These models analyze how different factors affect the Earth's energy budget and, consequently, its temperature. Fundamental Principle: first law of thermodynamics: Incoming solar radiation (shortwave) Outgoing terrestrial radiation (longwave) The difference between incoming and outgoing radiation determines whether the Earth warms or cools

53. Radiative forcing is the change in amount of energy in minus the amount of energy out due to external drivers such as increased greenhouse gases and aerosols. Positive radiative forcing means the planet warms and negative radiative forcing means the planet cools. This graphic displays some of the factors that can influence this energy balance on the planet. Graphic by Janelle Christensen.

54. Types of Climate Models Energy Balance Models (EBMs) : Fundamental equation can be expressed as: dE /dt = Rin – Rout Where: dE /dt represents the rate of change of energy in the system Rin is the incoming solar radiation Rout is the outgoing terrestrial radiation

55. Types of Climate Models Energy Balance Models (EBMs) : Types of Energy Balance Models Zero-Dimensional EBMs The simplest form treating Earth as a single point: Represents Earth as a uniform body Calculates global average temperature Assumes uniform distribution of energy Useful for understanding basic greenhouse effect principles

56. Types of Climate Models Energy Balance Models (EBMs) : Types of Energy Balance Models One-Dimensional EBMs Adds spatial variation in one dimension: Usually varies by latitude Accounts for north south heat transport Better represents pole-to-equator temperature gradients Includes ice-albedo feedback mechanisms

57. Types of Climate Models Energy Balance Models (EBMs) : Types of Energy Balance Models Two-Dimensional EBMs Incorporates both latitude and longitude: Represents land-sea contrasts Accounts for continental effects Models basic atmospheric circulation patterns Better represents regional temperature variations

58. Types of Climate Models Energy Balance Models (EBMs) : Advantages Computational efficiency Clear physical principles Easy to understand and implement Useful for approximations Limitations Simplified representation of complex processes Limited spatial resolution Cannot capture detailed dynamics May oversimplify important feedbacks Limited ability to represent regional effects

59. Types of Climate Models 2. Radiative-Convective Models (RCMs) simplified climate models that help understand the vertical temperature structure of the atmosphere by balancing radiative and convective processes. The atmosphere is divided into several (about 50) vertical layers. Each layer can either represent the global average conditions at that altitude or the average conditions over some particular location on Earth at a particular time. The radiative convective models are key to more complex models.

60. Types of Climate Models 2. Radiative-Convective Models (RCMs) RCMs consider two primary processes: Radiative Transfer: The absorption, emission, and scattering of radiation (both shortwave solar radiation and longwave infrared radiation from the Earth's surface). Convection: The vertical transport of heat due to buoyancy-driven motion, which helps maintain thermal equilibrium in the atmosphere. When the atmosphere becomes unstable (i.e., temperature decreases too rapidly with height), convection redistributes heat to restore stability.

61. Types of Climate Models 2. Radiative-Convective Models (RCMs) Advantages RCMs provide a fundamental understanding of vertical temperature distribution in the atmosphere without the complexity of full General Circulation Models (GCMs). Useful for studying the effects of greenhouse gases, cloud feedback, and radiative forcing on atmospheric temperature. Accounts for both radiative transfer and convective adjustment , making it more realistic than purely radiative models. Requires less computational power compared to GCMs, allowing for quick simulations and sensitivity analyses. Provides a basis for more advanced climate models, such as General Circulation Models (GCMs) and Earth System Models (ESMs).

62. Types of Climate Models 2. Radiative-Convective Models (RCMs) Limitations RCMs are one-dimensional (1D) , considering only the vertical structure and ignoring horizontal variations such as winds, ocean currents, and geographical differences. The convective adjustment is often a highly idealized process, typically assuming a fixed lapse rate rather than fully resolving convective dynamics. RCMs do not simulate complex interactions like Hadley cells, jet streams, or storm systems, which are critical for understanding regional climate variations. Typically, RCMs do not include detailed ocean-atmosphere interactions or the role of vegetation, making them less useful for studying fully coupled climate systems.

63. Types of Climate Models 3. Statistical Dynamical (SD) Models Statistical Dynamical (SD) Models are a sophisticated class of climate models that blend statistical analysis with simplified dynamical representations to simulate and predict climate system behaviors. Unlike purely physical models that attempt to simulate every detailed atmospheric and oceanic process, SD Models leverage statistical relationships derived from observational data to understand and project climate dynamics. SD Models rely heavily on empirical data and statistical techniques. They analyze historical climate records to identify patterns, correlations, and probabilistic relationships between different climate variables. While incorporating statistical insights, these models also include simplified dynamical representations of physical processes.

64. Types of Climate Models 3. Statistical Dynamical (SD) Models Advantages of SD Models Computational Efficiency: They are less computationally expensive than fully dynamical models. Improved Regional Accuracy: They can better capture fine-scale climate patterns compared to GCMs. Flexibility: Can be adapted to different climate variables and regions. Limitations Dependence on Historical Data: The statistical component relies on past observations, which may not always hold under changing climate conditions. Simplifications: SD models may not fully capture complex feedback mechanisms present in purely dynamical models.

65. Types of Climate Models 3. Global Circulation Models A Global Circulation Model (GCM) is a complex mathematical representation of the Earth's climate system that divides the planet into a three-dimensional grid of interconnected cells. These models numerically simulate the physical processes that drive climate dynamics, using fundamental laws of physics, fluid dynamics, and thermodynamics. Resolution of between 250 and 600 km, 10 to 20 vertical layers in the atmosphere and sometimes as many as 30 layers in the oceans.

66. Types of Climate Models 3. Global Circulation Models Fundamental equations solved in GCMs Conservation of energy (the first law of thermodynamics) i.e. Input energy = increase in internal energy plus work done 2. Conservation of momentum (Newton’s second law of motion) i.e. Force = mass x acceleration 3. Conservation of mass (the continuity equation) i.e. 4. Ideal gas law i.e. Pressure x volume is proportional to absolute temperature x density

67. Types of Climate Models 3. Global Circulation Models Components of GCMs Atmospheric Component (Radiation transfer, Cloud formation and precipitation, Atmospheric chemistry, Wind patterns and circulation) Oceanic Component (Ocean circulation and heat transport) Land Surface Component (Vegetation dynamics, Soil moisture, River runoff, Snow cover, Surface albedo)

68. Types of Climate Models 3. Global Circulation Models Types of GCMs Atmospheric Global Circulation Models (AGCMs) A numerical model that simulates only the atmosphere's physical and dynamical processes using prescribed sea surface temperatures and sea ice conditions. Ocean-Atmosphere Global Circulation Models (OAGCMs) A coupled model that simulates both atmospheric and oceanic processes, including their interactions and feedbacks, providing a more complete representation of the climate system. Earth System Models (ESMs) The most comprehensive type of climate model that incorporates OAGCM components plus biogeochemical cycles, ecosystem processes, and human influences to simulate the complete Earth system.

69. Types of Climate Models 3. Global Circulation Models Types of GCMs Regional Climate Models (RCMs) A high-resolution model focused on a limited geographical area, nested within global models to provide detailed climate simulations for specific regions. Earth System Models of Intermediate Complexity (EMICs) Simplified climate models with reduced computational requirements, designed for long-term simulations and multiple scenario analysis while maintaining essential climate system processes. CGCM (Coupled Global Circulation Model) Similar to OAGCM/AOGCM, representing models where multiple components of the climate system are coupled together for interactive simulation.