Climate Change and Global Warming Explained

What is climate change? What is the definition of global warming? What are the consequences of climate change?

You don't have to be a scientist to understand - we have broken down the most important bits and pieces for you.

If you're a teacher or parent, you can check out our Climate Change for Kids learning infographic. [coming soon]

Climate Change Definition

Climate Change refers to the long-term warming of our planet (global warming) as well as its resulting consequences, including sea-level rise, extreme weather, melting glacier and polar ice and the impacts that those changes have on humanity and natural ecosystems.

The world is warming and weather is becoming more extreme due to emissions of greenhouse gasses into the atmosphere from burning fossil fuels.

Causes of Climate Change

The cause of climate change is human activity - primarily due to the burning of fossil fuels, which generates greenhouse gasses. The Earth has always had a greenhouse effect, but the unnatural addition of greenhouse gasses to the atmosphere has disturbed the longstanding balance of the climate.

Greenhouse gasses, such as carbon dioxide (CO2), trap heat in the Earth's atmosphere. Without the natural greenhouse gasses in the atmosphere, planet Earth would be a big snowball - so having some greenhouse gasses in the atmosphere is a good thing. However, too many greenhouse gasses emitted from human activities is causing the planet to get hotter and changing many aspects of the global climate system.

The main greenhouse gasses are:

  • Carbon Dioxide (CO2)

  • Methane (CH4)

  • Nitrous Oxide (N20)

  • Chlorofluorocarbons (CFCs)

  • Water Vapor (H2O)

Global CO2 Emissions

Global CO2 (Carbon Dioxide) Emissions from 1900 to 2016 for the entire world are provided below. This data includes fossil fuel sources, cement production and flaring.

For more information on emissions by country, see our full report on carbon emissions from each country.

Climate Change Evidence: Global Warming is Caused by Carbon Dioxide and Other Greenhouse Gas Emissions

Carbon Dioxide emissions from human activities accumulating in the atmosphere are causing global temperatures to rise. This is easily observable in the data from the National Oceanic and Atmospheric Administration below, which shows atmospheric increases in CO2 and average global temperatures since 1959.

Demonstrating CO2 Cause and Effect - you can do it at home:

Carbon dioxide and other gasses producing the greenhouse effect is a well established fact - and is in no way considered speculative (although some media outlets have falsely stated so). In fact, it's possible to recreate this effect in a home laboratory experiment as demonstrated by Bill Nye:

So essentially the planet went from a stable equilibrium to humans burning a lot of fossil fuels (as seen in the graph above) - and this is what has destabilized the climate and triggered the climate to change. For approximately 400,000 years the concentrations of Carbon Dioxide have remained in a stable band between 170 parts per million and 300 parts per million.

Today the concentration of Carbon Dioxide in the atmosphere is 410 parts per million.

It is these emissions of carbon dioxide from burning fossil fuels that is causing the amount of carbon dioxide in the atmosphere to increase. Makes sense. If we are putting in millions of tons of carbon dioxide into the atmosphere every day, then we would expect to see a rise in the total concentration of atmospheric carbon dioxide.

That's exactly what is taking place.

Climate Change is More Than Just Global Warming

The globe is warming due to the increased amounts of trapped heat in the atmosphere and in the oceans. As we saw, this increased heat is caused by emissions of CO2 and other greenhouse gases.

The graph below shows that the annual temperature anomalies since 1880, when reliable annual records began. It's easy to see that the globe is significantly hotter today, with an increasing upward trend. Compared to the baseline of the 1950s to 1970s, the globe has warmed about 1.3 degrees F, on average. However, compared to the early 1900s, it's easy to see that the average temperature in 2017 was approximately 2 degrees F hotter.

Effects of Climate Change

For an infographic on the consequences of climate change if we don't act, click here.

Climate change has many consequences, ranging from the clearly demonstrated Global Warming to increased frequency and intensity of storms.

  • Global temperature rise - also known as global warming - is one of the most well known consequences of the changing climate. This means that the average temperature across the globe is increasing over time.

17 of the 18 hottest years have happened since 2000.
  • Warming Oceans - the oceans have absorbed a large portion of heat that has been trapped on Earth. The National Oceanic and Atmospheric Administration (NOAA) tracks many data points about the global oceans - including temperature and sea level rise.

  • Global Sea Level Rise - there are two components contributing to global sea level rise: primarily the amount of water in the ocean has increased due to melting of glaciers and land-based ice. When the total amount of water in the ocean increases, the sea level will rise - just like a bath tub getting filled up. The second cause of global sea level rise is the warming of the oceans - when substances are heated, they expand. As the ocean gets hotter, the total amount of space the water takes up increases - causing the ocean levels to rise.

  • Extreme Storms - extreme storms are increasing in number and power. Picture a pot of water on the stove. Now picture that water boiling. Which has more turbulence inside it? The boiling water of course. As the oceans and atmosphere increase in temperature, they act like the boiling water on the weather - the amount of energy for the average storm increases. That means larger storms, more frequent storms and more powerful storms.

In fact, 2017 was a record for total damage due to storms with damage exceeding $300 Billion from extreme weather events.
Climate Change has caused the number of huge storms with over $1 Billion in damage to increase - the number of storms causing over $1 Billion in damage are shown above. 2017 was a record year with over $300 billion in total damage from 16 storms which each caused more than $1 Billion in damage.

  • Ocean Acidification - because the ocean absorbs a large amount of carbon dioxide, the carbon emissions actually make the ocean more acidic. In the past two centuries, ocean pH has decreased 0.1. This might seem like a minor change, but because the pH scale is logarithmic, this represents a 25 to 30 percent increase in acidity, which affects all species in the oceans to varying degrees. One famous example is the bleaching of the Great Coral Reef in Australia - huge sections of it have turned white and are in danger of dying because of increased ocean acidity.

  • Changing Rainfall Patterns - Rainfall patterns are driven directly by the cycle of evaporation, condensation and precipitation. As the Earth get hotter, the atmosphere holds more water and evaporation is more likely, which means that rainfall gets bigger and faster. The impacts from changing rainfall patterns are already seen across the globe increased flooding and increased draughts.

And then there are many more - too many to outline in such detail - including:

  • Shrinking Ice Sheets

  • Shrinking Glaciers

  • Declining Arctic Sea Ice

  • Decreased Snow Cover

Now let's talk about what we can do about all this.

Climate Change Solutions

Each stage of the climate change system has its own set of solutions, which are broken down into 5 stages here.

Solutions to the core problem of fossil fuel-caused emissions are:

1. End fossil fuel use

2. Maximize renewable energy to provide long-term sustainable energy

3. Reduce energy demand

Solutions to additional sources of greenhouse gas emissions include:

1. Industrial CO2 management, often called Carbon Capture and Sequestration

2. Implement sustainable agriculture, which requires fewer resources and releases less carbon from the soil

3. Prevent deforestation, which is also a large cause of greenhouse gas emissions globally

Solutions to deal with the changing climate ecosystem are based on reversing the core changes in the climate system, particularly high CO2 levels and reflectivity of the Earth:

1. Allow natural carbon sinks to do their job - protect forests and oceans

2. If required, humanity may need to implement carbon removal technology on a large scale

3. Increase reflectivity by mandating white roofs, green roofs and light-colored manmade structures - these have benefits for reflectivity while also improving conditions inside the building by preventing the need for some air conditioning.

Adaptation to Climate Changes

Because of the changes in climate, cities and countries will need to adapt to the changed conditions. One example of this is taking into account sea-level rise when building city infrastructure.

Critical pieces of infrastructure often have long timelines of use, but could be greatly impacted by higher sea level. Think about your nearest coastal city's infrastructure, like roads, water treatment, electricity, railroads. It was most likely built to withstand the largest likely flood foreseeable based on sea levels from the 1960s. However, since the sea level has risen, there are changes that must take place to prepare for flooding based on the new, higher sea level.

Coastal cities are just one example of obvious impacts of sea-level rise, but all cities globally will have to adapt to new weather patterns including heavier rains and deeper draughts. That means we need better infrastructure to deal with extreme weather.

Getting prepared to deal with stronger weather is most easily done today, when the cost of preparation is low rather than paying to clean up after a disaster.

Lower Your Carbon Footprint

We each have a responsibility when it comes to the cause of climate change: carbon emissions.

Read our guide on how to lower your carbon footprint and take individual action to reduce carbon emissions.

Read about carbon offsets and why they are a good way to take individual action to reduce carbon emissions.

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