Lesson 5:

Human Causes of Climate Change

What you should know by the end of this lesson:

Know the human causes of Climate Change

Climate Change as we know it is most commonly to be understood as the impact of humans over the last 120 years (or so).

Climate Change Causes Worksheet

Climate Change Causes Factsheet

Digital Workbook and Paper Jotter

Collect the Climate Change Causes worksheet
Using the information below or the fact sheet to fill in the boxes with information about how human factors affect the global climate

Burning carbon-based fossil fuels

Fossil fuel consumption has been on the increase for the last 250 years since the industrial revolution. Fossil fuels such as coal, gas and oil when burned release Carbon Dioxide (CO2). Power stations and factories release huge amounts of CO2 on an almost constant basis around the world.

The increase in car usage and heating homes has continued this usage through the 20th and 21st century. Air travel has also increased with large emissions coming from jet planes and rockets.

Greenhouse gases are the primary cause of trapped heat inside our atmosphere which warms our planet.

Nitrous oxides are another Greenhouse Gas which is increasing as it is released from car exhausts, power stations and nitrogen-based fertilisers (in farming)

Methane Product

Methane is the name for the chemical compound CH4

it is a very prominent Greenhouse Gas which disappears from our atmosphere fast than CO2. Despite being removed from the atmosphere faster than Carbon Dioxide it is 84% more efficient at trapping heat.

Several people last year chose to do this as their assignment topic, analysing if Carbo Dioxide or Methane has more of an impact on Climate change.

Methane is produced in three main ways

Animal Flatulence

Livestock such as cows, pigs, sheep and other animals produce 14.5% of the world’s methane. A single cow releases 30 to 50 gallons of methane every day, with an estimated 1.5 billion cows on the planet, livestock farming is a huge producer of methane gas.

Countries which previously had a vegetatian diet (India and China) are changing to a more meat based diet as they develop. Increasing the amount of livestock on the planet.

Rubbish Dumps

When we throw things away into landfill sites they begin to degrade and decompose, this process releases methane gas. As we throw more and more away landfill sites become more common and larger, creating more methane gas.

A secondary danger of this is in some cases this methane gas can become trapped and explode.

Food Waste & Production

Increasing population especially in developing countries has meant that landfill sites are becoming bigger and fuller.

In places like China and India, the 2 largest world populations, rice is a staple food grown in large quantities. To produce large quantities of rice, paddy fields need to be flooded which then decays organic matter producing methane gas.

In countries like the UK and USA, we throw away large amounts of food. 6.6 million tons of food is thrown away a year by UK households. 70% of this food is actually still edible and need not of been thrown away.

Deforestation

Deforestation is the process of clearing large areas of trees.

Trees absorb CO2 converting it into useful sugars it can use to grow, a by- product of this conversion is Oxygen. Carbon is then stored within the tree, when forests are cleared this is normally done through fire clearing, just burning down the trees.

As the trees are destroyed, they then release CO2 back into the atmosphere. Deforestation stops the absorption of greenhouse gases and releases more store gases into the atmosphere causing the planet to warm.

CFCs (Chlorofluorocarbons) & HCFCs (hydrochlorofluocarbons)

CFCs became famous as the cause of Ozone depletion. This caused the Montreal Protocol in 1987 and actually saw the phasing out of CFCs from most countries to protect the Ozone layer.

CFCs had quickly become a key part of society being used in refrigeration units (fridges), aerosols and air conditioning units. They were replaced by HCFCs, not so damaging to the Ozone but just as damaging to the Climate.

However, against Carbon Dioxide some HCFC combinations have a GWP (Global Warming Potential) of 1000+, so while they are not as common their potential over 100 years is far higher.