Earth’s climate is changing, resulting in numerous effects on our environment and our well-being. For instance, heavy rains can lead to biodiversity loss and the spread of diseases, while rising global average temperatures can lead to ocean acidification. The effects of climate change are various, but all of them affect humans in one way or another.
What is climate change in simple terms?
Climate change is defined as long-term changes in temperature and weather patterns. It occurs due to human activities and natural processes, all of which increase the Earth’s average temperature. From the 1800s, human actions have been the primary cause of climate change due to the burning of fossil fuels.
See also: Top 10 world problems and their solutions
What causes climate change: Human impact vs nature
By far the biggest cause of climate change is the burning of fossil fuels, such as coal, oil, and gas. These are responsible for more than 75% of greenhouse gas emissions worldwide, according to experts from the United Nations.
By examining many indirect indicators of climate, including ice cores, tree rings, glacier lengths, and ocean sediments, as well as by tracking variations in the way the Earth revolves around the sun, researchers have managed to piece together a historical picture of the planet’s climate.
Although this data demonstrates that the climate fluctuates naturally over a broad range of time scales, the warming that has been witnessed since the 1950s is due to more than simply natural fluctuations.
Let’s examine how humans are causing climate change:
Greenhouse gases and albedo
Climate change has been significantly influenced by human activity through greenhouse gas emissions and the increasing albedo of Earth’s surface.
Greenhouse effect
The greenhouse effect occurs when heat becomes trapped on the surface of our planet by chemicals known as ‘greenhouse gases’ which contribute to climate change.
The Fifth Annual Climate Assessment states that today the levels of CO2, methane, and nitrous oxide in the atmosphere are higher than at any time over the last 800,000 years.
According to the National Snow and Ice Data Center, back then, based on high-resolution Antarctic ice-core data, the levels of carbon dioxide varied between 180 and 300 parts per million.
However, since the beginning of the Industrial Age (mid-18th and the beginning of the 19th centuries), the levels of CO2 have been on the rise, and data from the National Oceanic and Atmospheric Administration (NOAA) Global Monitoring Laboratory shows that, as of February 2025, CO2 emissions stood at 426.13 parts per million.
Source: EPA
By estimating the levels of greenhouse gases since pre-industrial times, scientists have found that human activities have:
- Annually, led to the emission of around 35 billion tons of CO2 into the atmosphere.
- Elevated methane levels to 1,922 parts per billion (ppb) in 2023 – over 2.5 times more than in the 18th century when this figure was at 722 ppb.Elevated the levels of nitrous oxide by 20%, from 270 ppb to 337 ppb in 2023.
Changes in land use, such as farming, desertification, and deforestation, impact Earth’s reflectivity (remember the albedo described above?)
See also: The effects of deforestation on humans, the environment and biodiversity
The Earth’s albedo on average is roughly 0.35. This indicates that roughly 65% of the energy from the sun that strikes the surface of planet Earth is absorbed, and the remaining 35% bounces back into space.
While changes in albedo can influence regional cooling or warming, the constantly growing concentrations of CO2 and other greenhouse gases in the atmosphere are the primary drivers of the Earth’s changing climate.
Farming, road construction, and forest destruction influence the amount of sunlight that the surface of our planet reflects or absorbs:
- Urban areas (called heat islands) tend to be warmer because various buildings and roads reflect less sunlight than forests or grassland.
- Aerosols – microscopic particles in the air – originate from both natural and man-made sources, such as the burning of fossil fuels.
Based on their type, aerosols either absorb sunlight (warming) or reflect it (cooling), which has an impact on the climate. Aerosols also affect clouds, altering their rainfall and reflectance.
Effects of global warming, or how hot will Earth be in 2050?
Today, scientists can collect enormous amounts of weather- and climate-related data from satellites, weather balloons, weather stations, and other devices and this data suggests clear evidence that the Earth is warming.
Scientists have found that:
- Since 1880, up to 2024, the average world temperature has risen by nearly 1.3 degrees Celsius and will continue to do so in the coming decades.
- By 2050, the average temperature is expected to rise by at least 2.4 degrees Celsius.
Natural causes of climate change, according to NASA
However, our planet’s climate can also change due to natural factors. Volcanic eruptions, variations in solar radiation, tectonic movements, and even minor adjustments to our orbit have collectively had noticeable impacts on patterns of global warming and cooling throughout Earth’s history.
NASA experts explain that although these natural causes still play their role in climate change, they take place too slowly to provide an explanation for Earth’s rapid warming over the recent decades.
Some of the natural causes that lead to climate change include:
Volcanic activity
The climate has been significantly influenced by volcanoes, the eruptions of which have emitted significant amounts of carbon dioxide and aerosols.
- The emitted CO2 plays its role in warming the planet although humans produce 50 times more CO2 than volcanoes.
- Significant amounts of aerosols (ash, dust, sulfur dioxide) block sunlight and can then cool the Earth for one to two years.
Orbital changes (Milankovitch Cycles)
Long-term changes in Earth’s tilt and orbit impact how much sunlight reaches various regions:
- Eccentricity – the orbit’s shape changes every ~100,000 years
- Obliquity – the tilt of Earth’s axis shifts every ~41,000 years
- Precession – Earth’s axis wobbles like a spinning top every ~23,000 years
These shifts can cause ice ages or warmer periods, particularly when they overlap in specific ways.
Variation in solar radiation
Because of sunspots which occur in an 11-year cycle, the amount of energy that the sun produces varies.
- More sunspots mean somewhat more solar energy, which ultimately can warm the planet.
- Fewer sunspots mean less energy and thus can have a cooling effect on the planet.
Movement of tectonic plates
Continents have been moving on Earth for millions of years, and this movement leads to the formation of volcanoes and mountains.
We already know about the impact of volcanic eruptions but the large mountain chains can impact the global circulation of air, ultimately affecting the climate. For instance, mountains may deflect warm air to colder areas.
El Niño-Southern Oscillation (ENSO)
The ENSO represents a natural climate pattern that takes place every two to seven years. It involves variations in ocean temperature and has an impact on the atmosphere above the Pacific Ocean. ENSO has three phases:
- El Niño – this is when the ocean warms, and less cold, nutrient-rich water rises in the vicinity of South America.
- La Niña – the temperature of the ocean drops, and east-to-west winds increase in strength.
- Neutral – conditions are normal.
See also: What are the potential impacts of El Niño on the weather and socio-economic situation in 2023-2024?
The global mean temperature may rise when the climate changes from La Niña to El Niño and, if coupled with climate change, this can lead to extreme heat.
What are the consequences of global climate change?
The past 100 years have witnessed a serious transformation climate-wise, with numerous pieces of evidence illustrating changes in our planet’s weather, as well as changing oceans and ecosystems.
The World Health Organization has reported that in the last 10 years, floods, droughts, tropical cyclones, heatwaves, and powerful storms have accounted for 80–90% of all natural catastrophes that have been reported.
Here’s how climate change continues to impact our planet:
🔹 The effects of climate change on water
With the increase in global temperature, more water evaporates, and thus more precipitation occurs.
Rain and snow are vital for the planet as they provide water for drinking, farming, and industry.
However, too much precipitation has some serious consequences:
- Increased precipitation can lead to flooding.
- Snowfall, rainfall, and the time of snowmelt can all impact the quantity of groundwater and surface water.
- If rainfall patterns change too quickly, this can harm ecosystems that cannot adapt in time.
Climate change also affects wind and ocean patterns, which means that some regions may lack rainfall.
🔹 The effects of climate change on food
Farmers face difficulties due to heatwaves and rising temperatures, diseases, and water shortages.
Here’s how climate change affects the food-chain:
- Extreme weather conditions, changes in rainfall patterns, and temperature rise can all lower the amount of food that farmers produce.
- Certain countries’ food supply issues can have a negative impact on other countries, causing price increases, a higher chance of crises, and even national security issues.
- Weather variations can also cause delays in the delivery of food:
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- Roads can become impassable due to flooding, hurricanes, ice, and/or strong winds.
- Heat can impact food.
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🔹 Climate change impact on flora and fauna
Although not equally, all living creatures and the environments in which they reside are impacted by climate change, particularly through rising sea levels, storm surges, soil erosion, droughts, warming waters, and ocean acidification.
Ice loss
NASA experts state that since 2002, Antarctica has lost around 136 billion tons of ice every year while Greenland has lost 267 billion, all of which leads to rising sea levels and the loss of habitat for the animals that live there.
Ocean acidification
Around 30% of the carbon dioxide generated by the burning of fossil fuels is absorbed by the ocean, which makes the ocean waters more acidic, thus harming marine life.
Coral reef bleaching and destruction
Thousands of species can be found in coral reef environments. Strong hurricanes can damage reefs, and warming oceans can cause coral bleaching which involves the algae that live in the tissues of corals being expelled, turning the coral white.
See also: Coral bleaching at highest rates ever: Marine life, environment and livelihoods at risk
Invasive species
To adapt to the changing conditions, some species migrate to new geographical areas. Although this may help them to survive, it can negatively impact the native species in those ecosystems.
Wildfires
Numerous animals suffer the effects of wildfires, losing their habitats and facing chronic stress due to a lack of food and shelter and a higher chance of predation.
How does a changing climate impact our health?
Both our health and that of the planet are intertwined. Based on BC Centre for Disease Control Data, here are some of the health concerns associated with climate change and how to mitigate these:
🔹 Extreme heat events
Heat events can:
- Increase the risk of heat-related problems such as heatstroke and dehydration
- Intensify existing medical issues such as lung and heart diseases.
- Lead to fatalities due to extremely high temperatures.
🔹 Flooding
Flooding can cause fatalities and serious injuries and can also result in a higher chance of contracting infectious diseases from contaminated food and water. Abundant precipitation can also cause mold to grow indoors.
🔹 Wildfires
Not only do wildfires pose a death risk to all living things, but their smoke also pollutes the air, impacting our health, even if we are far from the fire.
🔹 Infectious diseases
Various factors such as extreme temperature fluctuations and an increase in or a lack of precipitation may force some insects and animals to find another place to live, sometimes near humans, which increases the chances of being exposed to certain diseases they carry.
🔹 Food safety
Due to rising temperatures and shifting ocean chemistry, humans are at greater risk of coming into contact with marine pollutants and diseases in seafood. In addition, power disruptions due to extreme weather events can lead to food spoiling.
See also: Drought and famine: their causes and relationship
🔹 Mental health
Both individuals at risk and those without a history of mental illness experience an increase in mental health issues after disasters. CDC says that such a phenomenon is called “common reactions to abnormal events.”
🔹 Pollen
A higher level of CO2 in the air, along with higher air temperatures and fewer frosty days, can impact the pollen season, namely its duration. People exposed to pollen are at risk of developing hay fever, or allergic rhinitis, and other allergic reactions.
Responding to climate change through mitigation and adaptation
We can react to climate change in two complementary ways: mitigation and adaptation, according to MIT experts. But what do these two terms mean?
- Mitigation refers to reducing greenhouse gas emissions to limit future warming.
- Adaptation means adjusting to the climate change’s effects of today and tomorrow.
How does climate change mitigation work?
Dealing with the excess of greenhouse gases in the atmosphere can be achieved by:
- Shifting from fossil fuels to renewables and nuclear energy
- Keeping forests safe and capturing methane from landfills
- Planting new trees
- Employing new technologies such as Direct Air Capture (DAC) which although helpful, would need to be accompanied by a cut in emissions
According to the Intergovernmental Panel on Climate Change, renewable energy sources (bioenergy, solar and wind power, geothermal energy, hydropower, and ocean energy) have the ability to reduce greenhouse gas emissions from the burning of fossil fuels and contribute to climate change mitigation efforts.
We need adaptation.
How does climate change adaptation work?
Adaptation may vary from region to region, but generally, it involves:
- Upgrading infrastructure: building more storm drains, flood-control systems, etc.
- Focusing on natural solutions: creating new, more resilient food crops and restoring wetlands to act as storm buffers.
Final word
The climate continues to change, and much more action is needed from individuals, businesses, and governments alike. Without meaningful efforts, the situation may worsen, especially in the most vulnerable regions. Continued inaction may result in more extreme droughts, heavier rainfall, loss of biodiversity, and rising health risks for people around the globe.
