TOPIC 1: What climate change is about ?

TOPIC 1: What climate change is about ?

Comprehensive exposition of global climate change based on the current state of the science. 

We have been familiar with climate change as a term for quite a long time. At first, we heard the term global warming most often, but soon enough it became obvious that we were facing a much more complex threat to both the Earth’s living world and the systems created by mankind. Raising the average temperature is just one element of the story since the Earth is a system. On our planet, everything is nicely connected. So if one area is changing it could influence changes in all others.  Fortunately, over time, the voices denying the existence of climate change have become quieter and more emphasis has been placed on results and predictions backed by committed and credible experts and organizations with scientific backgrounds. 

More and more people are aware of the significance of the problem and want to learn more about the possible causes, and the options for intervention and, as responsible citizens and active members of the local community, take action to improve the situation.   

We look forward to supporting this great ambition in this module.

What is climate change?

There are many definitions of climate change. “Climate change is a long-term change in the average weather patterns that have come to define Earth’s local, regional, and global climates. These changes have a broad range of observed effects that are synonymous with the term.” (*) can be read on NASA’s Global Climate Change homepage. According to the UN Climate Action, “Climate change refers to long-term shifts in temperatures and weather patterns. Such shifts can be natural, due to changes in the sun’s activity or large volcanic eruptions.” (*). Recognizing that there can be natural causes for a changing climate, scientists agree that human activities have a main role in the process. 

Since the 1800s, our activities, primarily the burning of fossil fuels like coal, oil, and gas have generated radical changes in the Earth’s climate. Technological advances that make our lives more comfortable, predictable, and secure seem to threaten our long-term survival on the planet. 

Experts say that we’re in the midst of a sixth mass extinction. Mass extinction means a short period of geological time (which can span thousands or even millions of years) in which a high percentage of biodiversity (including distinct species) disappears from the Earth. Our planet has experienced five previous mass extinction events, the last one occurring 65.5 million years ago which abolished the last dinosaurs. Unlike the natural phenomena caused by previous extinctions, the Anthropocene extinction (6th or Holocene mass extinction) is not limited to, but mainly driven by human activity. The unsustainable use of land (e.g. intensive, monoculture industrial agriculture), water and energy use, and climate change as a whole have a tragically harmful effect on the Biosphere.

The biosphere is the thin life-supporting stratum of Earth’s surface, extending from a few kilometres into the atmosphere to the deep-sea vents of the ocean. It is composed of living organisms and nonliving factors from which the organisms derive energy and nutrients.

Source: downloaded: 25/07/2023

1. Causes of Climate Change

Generation of power 

The use of renewable energy sources has expanded rapidly in recent years, but the share of global electricity generation of renewables (solar, wind, hydro, biofuels, and others) is still just 28% of the total one. The transportation and heating sectors do not keep up with the pace of the energy transition and stayed at the position dedicated to one of the biggest emitting sectors in connection with greenhouse gas (reference to lesson 2) production. (*)


The manufacturing industry is responsible for the largest greenhouse gas emissions globally. Its emission comes from burning fossil fuels for energy production which is needed for making e.g. electronics, clothes, steel, iron, cement, plastics, and other products. Machines used in processes mostly run on oil, coal, or gas. Materials, like plastics are made of fossil fuels-sourced chemicals. 


Each and Every year around 12 million hectares of forest are disappearing from Earth. Destroying the forests for any reason (e.g. to create farms or pastures for livestock) endangers the natural, but vulnerable balance of the atmosphere. Trees are not just absorbing carbon dioxide, but doing the opposite when they are cut and burnt: releasing the carbon they have been storing. According to estimations, deforestation, unsustainable agriculture and other harmful land usage together are responsible for about 25% of global greenhouse gas emissions.


Transportation is a major contributor to the emission of greenhouse gases (esp. co2) with nearly ¼ of global energy-related carbon-dioxide emissions. According to the relevant tendencies, a significant increase in energy use for transport is predicted over the coming years. Majority of the cars, trucks, ships, and planes run on fossil fuels. Road vehicles have the leading role in emissions, but due to the emerging number of ships and planes contributing to global transportation, their emission rate is growing as well. 

Food production

Just as the previous ones food production causes emissions of carbon dioxide, methane, and other greenhouse gases in various ways. Almost all of the relevant activities in connection with it (through deforestation, changes of land for monoculture agriculture and grazing, production and use of fertilizers and pesticides, digestion by livestock, the use of energy to run machines and tools.) along with packaging and distribution of food makes this sector a major contributor to climate change. 


Most of the human activities contribute to greenhouse gas emissions. The way how you use power at home, how you move around, or what and how you eat, etc. influence greenhouse gas emissions. So the consumption of any kind of things such as plastics, electronics, machines, clothing, etc. make pressure on our environment. Our lifestyles have a significantly big impact on our planet since our private households emit large amounts of greenhouse gases. 

Powering buildings

Who is responsible for consuming more than half of the global electricity? The residential and commercial buildings.  As they continue to draw on coal, oil, and natural gas for heating and cooling, they emit significant quantities of greenhouse gas emissions. More and more energy is needed for heating and cooling. The rising number of air-conditioners, lighting, appliances, and connections need electricity. Obviously, it increases the energy-related carbon-dioxide emissions of buildings.

2. Effects of Climate Change

The consequences of climate change are not just topics of scientific conversation. Some of them are experienced in our private life while others frequently show up in the headline of the News. Rising sea levels, bush and forest wildfires, melting polar and glacier ice, droughts leading to water and food scarcity, flooding, never seen storms, and declining biodiversity. These are those phenomena we have to face almost every day.  


According to the global surface temperature, each decade of the period since the 1980s has been warmer than the previous one. The rising concentration of greenhouse gases in the atmosphere makes the Earth a hotter place. The last decade was the warmest one on record so far. Melting ice surfaces decreases the albedo (a unit indicating the reflectivity of the earth’s surface) which has a direct influence on the global greenhouse effect. Almost all land areas have more hot days and longer heat waves, which increases heat-related illnesses and makes outdoor-works more difficult. 

Destructive storms

Storms have become more intense and frequent in many regions of the Earth. Destructive storms have a direct connection with rising temperatures. The warming ocean influences the frequency and extent of tropical storms. Cyclones, hurricanes, and typhoons are responsible for deaths and huge economic losses, destroying homes and communities.

Drought and famine 

The ecosystem of Earth has become highly vulnerable. There is no life without water. Climate change caused problems in the availability of water in already water-stressed regions and is leading to an increased risk of agricultural droughts affecting crops everywhere. Droughts can also excite sand and dust storms moving billions of tons of sand all over the continents. Expanding deserts reduces the size of land for growing food. Millions of people face the threat of not having enough water and food on a regular basis. Behind the increasing hunger and poor nutrition, we can find the changing climate as the main reason. The productivity of livestock, crops, and fisheries is decreasing. Changes in snow and ice cover in many Arctic regions and the melting permafrost complicates the food supplies from herding, hunting, and fishing. 

A warming, rising ocean

The ocean covers more than 70 % of the surface of the Earth with an enormous heat capacity, soaking up most of the heat from global warming. The ocean is warming faster over the past two decades. The warming ocean’s volume increases since water expands, and the sea level is rising. Melting ice surfaces also makes sea levels rise, threatening coastal and island communities. In addition, the ocean absorbs carbon dioxide, keeping it from the atmosphere. But more carbon dioxide makes the ocean more acidic, which endangers marine life and coral reefs.

Loss of species

Our world is losing species at a rate 1,000 times greater than ever before in recorded history. 1 million species are at risk of extinction within the next few decades. Species on land and in the ocean are fighting for their survival in extreme weather conditions, frightened by invasive pests and diseases.   

More health risks

Environmental factors take the lives of ca. 13 million people annually. Extreme weather events, heat waves ,air pollution, various diseases, forced displacement of people,pressures on mental health, and increased hunger and poor nutrition make our lives harder. These risks increase deaths and put enormous pressure on healthcare systems. 

Poverty and displacement

Over the past decade, climate-related events displaced approx. 23 million people on average yearly. Climate change has direct connections to the factors that put and keep people in poverty. Droughts, water scarcity, floods, etc. worsen the living conditions of the most vulnerable groups in society. Climate-related refugees mainly come from those countries that are the most vulnerable and least ready to adapt to the changing climate.

The temperature in the Arctic warming up at least twice as fast as the global average.

The global ocean has absorbed 90 % of the warming of decades due to increasing greenhouse gases.

267 million people live on land less than two meters above sea level worldwide at risk from sea level rise and this number is predicted to increase to 410 million by 2100. 

The agricultural land area is approximately 5 billion hectares (38 %) of the global land surface, and just 1/3 of this is used as cropland. The remaining 2/3 is for grazing livestock.