Climate Change Basics

What is Climate?

• Climate refers to the long-term average of weather patterns in a particular region over an extended period, typically 30 years or more. It represents the average weather conditions, including temperature and precipitation, for a specific area. Climate gives a broader picture of the typical atmospheric conditions in a particular region over an extended period. 

Do not confuse Climate and Weather. 

While weather describes the short-term atmospheric conditions, climate encompasses the long-term patterns and averages of weather in a specific region. It's crucial to differentiate between the two when discussing topics related to Earth's atmosphere and environmental changes.

• Weather refers to the short-term atmospheric conditions in a specific location, including elements such as temperature, humidity, precipitation, wind speed, and atmospheric pressure. Weather describes what is happening in the atmosphere at a particular place and time.

Climate Zones  

Climate zone classifications are derived from the Köppen-Geiger climate classification system, which divides climates into five main climate groups divided based on seasonal precipitation and temperature patterns. The five main groups are: A (tropical), B (dry), C (temperate), D (continental), and E (polar). All climates except for those in the E group are assigned a seasonal precipitation sub-group (second letter). 

For RoM islands, the climate zones are all tropical:

1. Mauritius:   Af; Am
2. Rodrigues: Am
3. Agalega: Af
4. Cargados Carajos: Af
5. Chagos Archipelago: Af
6. Tromelin: Af 

where  Af signifies Tropical Rain forest and  Am signifies Tropical Monsoon Climate.

What is Climate Change?

It is difficult to talk about climate without mentioning the current climate change caused by human activities.

Climate change, as per the United Nations Framework Convention on Climate Change, (UNFCCC), refers to a change in the state of climate that alters the composition of the global atmosphere and that is in addition to natural climate variability observed over comparable time periods.   

Climate change stems from changing the natural climate balance. This natural climate balance is the permanent interaction between the atmosphere (thin gas envelope composed mainly of nitrogen at 78% and oxygen at 21%), continents, oceans and ice.

The relationships between these sets generate many physical, chemical and biological processes and influence temperatures, winds and precipitation. This climate complex is regulated by greenhouse gases (GHGs), which are present in small quantities in our atmosphere, they form a “barrier” around the Earth, and make it possible to retain the earth's heat emitted by the Sun. They allow an average temperature of 14 °C and for life to develop, and without them the temperature on Earth would be -18 °C.

However, since the end of the 20th century, greenhouse gases have increased considerably as a result of human intervention. This increase in greenhouse gases is leading to global warming.

(source: UK Met Office, Accessed 19/09/2024)

Since the 1850s, average global temperatures have increased by over 1°C. The years 2015 through 2020 rank as the warmest on record, underscoring a significant warming trend that began with the Industrial Revolution. 

As climate change progresses, many regions around the world may become increasingly difficult to inhabit. This could force people to leave their homes. While climate is just one of several factors influencing human migration, its impact is expected to grow in the future.

Understanding the Greenhouse Effect and Its Role in Climate Change

The greenhouse effect is a natural process where greenhouse gases like carbon dioxide trap heat within the Earth's atmosphere. These gases act like a blanket, allowing sunlight to pass through to the Earth's surface while trapping outgoing infrared radiation. This warms the planet and is essential for sustaining life by keeping temperatures at a livable level. 

However, human activities have intensified this effect by adding more greenhouse gases to the atmosphere, making the blanket thicker and trapping more heat. This enhanced greenhouse effect is causing the Earth to heat up, contributing to climate change.

Sources of Greenhouse Gases

Greenhouse gases originate from various natural and human-made sources:

Burning of Fossil Fuels: The combustion of coal, oil, and natural gas for energy and transportation is the primary source of carbon dioxide and a significant source of nitrous oxide.

Agriculture: Practices such as rice cultivation, livestock raising (which produces methane through enteric fermentation), and the use of nitrogen-based fertilizers (which emit nitrous oxide) contribute substantially to greenhouse gas emissions.

Deforestation: The removal of forests, particularly through burning, releases carbon dioxide stored in trees and reduces the planet's capacity to absorb existing carbon dioxide.

Industrial Processes: Certain industrial activities emit various greenhouse gases, such as the production of cement, which releases carbon dioxide, and the use of refrigerants, which release fluorinated gases.

Waste Management: Landfills produce methane as organic waste decomposes anaerobically. Additionally, wastewater treatment can also emit methane and nitrous oxide.

Water Vapour: While not directly emitted through human activities, water vapour is the most abundant greenhouse gas and plays a critical role in the climate system. As the Earth’s surface warms, more water evaporates, increasing atmospheric water vapour, which in turn traps more heat and enhances the greenhouse effect in a positive feedback loop.

These sources combine to increase the concentration of greenhouse gases in the atmosphere, intensifying the greenhouse effect and contributing to global warming.

Key Impacts of Climate Change

Human activities, including the emission of greenhouse gases and aerosols along with changes in land use, are the main catalysts of climate change. This phenomenon has profound impacts on climate systems, ecosystems, and human communities globally, leading to changes that threaten the balance necessary for both natural environments and human societies to thrive.
The widespread and pronounced impacts of climate change necessitate immediate and collective global action in mitigation and adaptation efforts. These strategies are crucial not only for the survival and well-being of affected communities but also for the conservation of global biodiversity and environmental health.

Impacts on the Climate System

Rising Ocean Levels: Melting glaciers and ice sheets, exacerbated by rising global temperatures, cause seawater to expand thermally, leading to higher ocean levels that threaten coastal regions worldwide.
Increased Temperature and Heat Extremes: Various regions are experiencing rising temperatures that amplify heat-related illnesses, disrupt traditional lifestyles, and pose serious risks to biodiversity.

Impacts from Natural Disasters

Increased Frequency and Severity: Climate change contributes to the increased frequency and intensity of natural disasters like cyclones, hurricanes, and floods. These events lead to significant immediate and long-term economic impacts due to damages and the costs associated with recovery and reconstruction.

Impacts on Ecosystems

Ocean Acidification: The oceans' increased absorption of carbon dioxide results in greater acidity, negatively impacting marine life, often described as the 'evil twin' of climate change.
Coral Reefs and Marine Ecosystems: Increased coral bleaching events and ongoing ocean acidification damage marine ecosystems crucial for biodiversity and as natural barriers against storm surges.
Water Resources: Altered rainfall patterns and increased drought frequency exacerbate water scarcity. Rising sea levels and storm surges also contaminate freshwater reserves with saltwater.
Natural Habitats: Disruption in natural habitats due to altered climates leads to species migration, adaptation challenges, and potential extinctions.

Impacts on Human Communities

Extreme Weather Events: The intensity and frequency of extreme conditions such as heatwaves, droughts, and severe storms disrupt lives and infrastructure.
Food Security: Dependencies on global food supply chains make many regions vulnerable to fluctuations in food availability. Local food production faces threats from extreme weather, soil salinization, and broader impacts on fisheries due to ocean acidification.
Flooding and Displacement: Elevated sea levels heighten flooding risks in coastal areas, endangering infrastructure, residences, and lives, and leading to displacement and significant economic losses.
Conflict and Climate Migration: Exacerbated resource scarcity can trigger conflicts and compel populations to migrate in search of more favorable environments.

Are Extremes becoming more frequent?

Trends Observed

• Munich RE's Topics Geo Natural Catastrophes report reveal the following trends:
• Increasing Frequency: The overall trend shows a clear increase in the total number of loss events over the decades. This rise is most notable in meteorological, hydrological, and climatological events.
• Stability in Geophysical Events: The number of geophysical events appears relatively stable over the years. This suggests that such events are less influenced by climate change compared to weather-related events.
• Significant Rise in Meteorological and Hydrological Events: There is a marked increase in meteorological and hydrological events starting in the early 1990s, continuing to rise through 2016. This could be attributed to the increasing impact of global warming on weather patterns, leading to more frequent storms and flooding.
• Climatological Events: There is a noticeable increase in climatological events, particularly from the mid-2000s onwards. This aligns with global trends in rising temperatures and more frequent droughts and wildfires, which are exacerbated by climate change.

Implications

• The data suggests a correlation between the increase in certain types of natural disasters and climate change, particularly in the case of meteorological, hydrological, and climatological events. The consistent number of geophysical events underscores that not all types of natural disasters are influenced by climate change but rather by geological factors.

source: Munich RE's Topics Geo Natural Catastrophes report

(This graph underscores the increasing frequency of climate-related natural disasters over time, highlighting the need for enhanced disaster preparedness and adaptation strategies to mitigate these risks.)

Addressing climate change

Addressing climate change requires a multifaceted approach that spans policy, technology, and individual actions. There are numerous approaches to achieve this, and governments, businesses, organizations, and individuals globally can all play a role:

1. Reduce Greenhouse Gas Emissions:
   • Transition to Renewable Energy: Shifting from fossil fuels to renewable energy sources such as solar, wind, and hydroelectric power can significantly reduce carbon emissions.
   • Enhance Energy Efficiency: Improving energy efficiency in buildings, vehicles, and industries can lower energy consumption and reduce emissions.
2. Adopt Sustainable Practices:
   • Sustainable Agriculture: Implementing practices like crop rotation, organic farming, and reduced tillage can decrease emissions from agriculture.
   • Responsible Land Use: Preserving forests and natural habitats, and promoting afforestation and reforestation help sequester carbon dioxide.
3. Innovate and Deploy Carbon Capture Technologies:
   • Technologies that capture carbon dioxide from the atmosphere or directly from industrial sources can help reduce overall atmospheric CO2 levels. These technologies need scaling and economic integration.
4. Waste Reduction and Management:
   • Reducing waste through recycling, composting, and improving waste management systems can lower methane emissions from landfills.
5. Regulatory and Policy Measures:
   • Implementing policies that promote carbon pricing, emissions trading systems, and strict emissions standards can incentivize reductions in greenhouse gas emissions.
   • International Cooperation: Global problems require global solutions. International agreements like the Paris Agreement are crucial in setting and achieving emission reduction goals.
6. Education and Awareness:
   • Raising awareness about climate change impacts and solutions through education can empower individuals and communities to take action.
7. Invest in Research:
   • Funding research into new technologies and methods for reducing emissions and removing greenhouse gases from the atmosphere is essential for ongoing progress.
8. Lifestyle Changes:
   • Individuals can contribute by reducing air travel, using public transportation, consuming less meat, and conserving energy at home.

What is Net Zero?

"Net zero" refers to achieving a balance between the amount of greenhouse gases emitted and the amount removed from the atmosphere. Essentially, net zero is reached when the activities within a country, sector, company, or individual produce net zero carbon emissions, meaning that any emissions are counterbalanced by absorbing an equivalent amount from the atmosphere.

The key components of net zero:

Reduction of Emissions: The first step toward net zero is to drastically reduce greenhouse gas emissions across all sectors, including energy, transportation, agriculture, and manufacturing. This involves transitioning to renewable energy sources, enhancing energy efficiency, and adopting cleaner technologies and practices.

Carbon Removal: Any remaining emissions need to be neutralized through natural or technological solutions that remove carbon dioxide from the atmosphere. This can involve reforestation or afforestation projects, soil carbon sequestration practices, or technologies like direct air capture and carbon storage.

Sustainable Development: Reaching net zero is not only about reducing emissions but also ensuring sustainable development that does not compromise the ability of future generations to meet their needs.

Net zero targets are crucial for limiting global warming to well below 2 degrees Celsius, a goal of the Paris Agreement to mitigate climate change impacts. Countries, regions, cities, and companies around the world are setting net zero goals, aiming to achieve this balance by specific dates, typically around mid-century.

Adaptation and Resilience Strategies for SIDS

• Ecosystem-based Adaptation: SIDS are encouraged to integrate natural solutions such as mangrove restoration and coral reef conservation to enhance resilience against storms and erosion.

• Water Resource Management: Innovative practices like rainwater harvesting, desalination, and efficient irrigation are essential to manage scarce water resources.

• Sustainable Agriculture: Developing climate-resilient crop varieties and farming practices can help maintain food production.

• Infrastructure Resilience: Building and retrofitting infrastructure to withstand extreme weather events is crucial.

• Community Engagement and Policies: Strengthening local capacities and implementing forward-looking policies are key for long-term sustainability and resilience.