4.3 Climate change

• Aardrijkskunde
• Middelbare school
• havo, vwo
• Leerjaar 3

4.3 Climate change

How does the Gulf stream affect the climate?

“If we continue to drive global warming, the Gulf Stream System will weaken further – by 34 to 45 percent by 2100 according to the latest generation of climate models,“ concludes Rahmstorf. “This could bring us dangerously close to the tipping point at which the flow becomes unstable.”

Learning objectives

After studying this section, you will be able to:

• Describe natural and human reasons of climate change;
• State the most important greenhouse gases.

What is a greenhouse gas?

1. Carbon dioxide
2. Methane
3. Water vapour
4. CFK

The Earth’s temperature record

• Since 1850 thermometers are used to keep a detailed record of temperatures, using standardised procedures.
• Estimates up to 2,000 years ago: Climate scientists now use tree rings for land temperatures and coral growth rates for seawater temperatures.
• Scientists analyse air bubbles trapped in ice cores on Antarctica and Greenland.
• All pointed to a similar conclusion: the global climate has been changing since the formation of the Earth and warm periods have been interspersed with ice ages.

Figure 4.17 The global temperature record of the past 800,000 years compared to the current average temperature. The right side is the present day.

Holocene

The current geological epoch, the Holocene, is a relatively warm period with a stable climate. Scientists say the Holocene started a little over 10,000 years ago.

Talking point: The Earth’s climate has always been changing. Should we be concerned about recent changes?

Intergovernmental Panel on Climate Change (IPCC) = the international organisation which investigates climate change.

Natural reasons for 

changing climates

• Volcanic eruptions > large ash clouds > less solar radiation > lower temperatures on a very short timescale.
• Incoming solar radiation (insolation) > the sun doesn't emit the same amount of solar radiation on a longer timescale.
• Shifting tectonic plates on a very long timescale.

Human interference

• IPCC concluded in its most recent report that “it is extremely likely that human influence has been the dominant cause of the observed warming since the mid-twentieth century.”
• Effects: Before 2100, the global temperature will be at least 1.5°C higher than in 1900. This will lead to more extreme weather events such as heat waves, floods and droughts (paragraph 4.4).

The natural greenhouse effect (left) and human enhanced greenhouse effect (right).

The (enhanced) greenhouse effect

Since the industrialisation of the 1850s, people have used a considerable amount of fossil fuels (coal, oil and gas) to run factories, cars and other machines > more CO2 in the atmosphere > enhanced greenhouse effect.

Biggest contributers per economic sector:

1. Energy sector (burning coal, oil and gas)
2. Agriculture (due to cultivation of crops and livestock) and slash and burn deforestation.

Carbon cycle
= Model of stores and transfers of carbon throughout the Earth’s system.

Homework 3HT

Homework for 9 March:

• Study 4.3
• Read 4.3 and do ex. 1 to 7
• Finish this before wednesday next week

4.4 Consequenses of climate change

I think a consequence of climate change is......because...

In my opinion climate change will result in...... because....

Even more climate change will lead to.......because.....

It seems to me climate change will cause.....such as.......

Consequences of climate change

Homework: 4.4

Class: 4+ 7+ 9 => Atlas

Home: 1-5+ 8+ 11

4.3: 3,4,5 and 7