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Climate change

“We are currently in the sixth mass extinction and this time we are the asteroid” - Joe Hanson

 
 
 
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GRAB A PENCIL

Write down the first 3 things that come to mind when you think of Climate Change


Let’s not ignore the giant, rapidly melting icecap in the room.

Understanding the largest dilemma of our generation is no easy task. In this lesson we will define climate change, explore it’s causes and impacts, as well as identify local action on what is a global problem to solve.


DISCUSSION

Are there arguments against learning about Climate Change?


what is Climate change?

Climate is the mapping and modelling of weather over a long period of time.

 
 
 
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Climate change, sometimes referred to as global warming, is exactly what it sounds like: it is the changing of the Earth’s climate. When discussing climate change in the Anthropocene (see Lesson 3 - History of the Ocean), we are generally referring to the impacts of human activity.

To really understand climate change, we must first define what climate actually is.  

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Climate is the mapping and modelling of weather over a long period of time.

This data helps scientists identify patterns. It’s the big picture and includes temperature, humidity, atmospheric pressure, wind and rain.

By identifying these weather patterns, we get an idea of what our climate has been doing and what it should be doing.

IT WASN’T UNTIL THE MID 19TH CENTURY THAT WE WERE COLLECTING ENOUGH DATA IN ENOUGH PLACES TO CALCULATE OUT AN AVERAGE TEMPERATURE FOR THE WHOLE PLANET.

Warming the atmosphere

 
 
 
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The Sun provides nearly all of Earth’s heat (thanks for that Sun!).

Our atmosphere naturally contains greenhouse gases, without them the Earth would be way too cold - averaging a rather chilly -18 degrees instead of the nice and cosy average of 15 degrees that it is today. So the greenhouse effect is a natural atmospheric process that helps regulate Earth’s climate and protect us from the Sun’s harmful rays (not like Joni’s cute rays).

The problem is that humans are adding extra greenhouse gases into the atmosphere. Since 1900 the average global temperature has increased by 1 degree - most of which has happened since the 1970’s.

The more greenhouse gases that are released into our atmosphere, the thicker this protective blanket gets, trapping the sun’s thermal radiation on Earth.


QUESTION

Which gas do you suspect is heating up our Earth the most?



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Water vapour traps the most heat. In fact 1 in 200 air molecules is H2O, enough to trap about 1/2 the heat given off by Earth.

The gas that is capable of raising temperature the most is…

Sulfur Hexafluoride (SF6) is one of the heaviest gases - you could actually float a tinfoil boat on it. SF6 only exists because we synthesised it for us as an electrical insulator and and in the medical industry. Luckily there isn’t a lot of it in the atmosphere - only around 1 in 100,000,000,000 (one hundred billion) air molecules.

Methane (CH4) is the key ingredient in natural gas and it is being added into the atmosphere at an alarming rate. The biggest source of CH4 emissions are... cow burps (and cow farts). CH4 makes up approximately 1 in 600,000 air molecules.

WITH SUCH HIGH DEMAND FOR BEEF, MILK AND CHEESE, OUR AGRICULTURAL PRACTICES HAVE HAD TO KEEP UP WITH THE SUPPLY. MORE CATTLE = MORE METHANE = A THICKER ATMOSPHERIC BLANKET.


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The winner of the “Global Warming Award for Heating Earth the Mostest” goes to…

Carbon Dioxide (CO2), the gas produced when we burn fossil fuels and chop down trees is famous for a reason - there is so much of it! By burning fossil fuels humans have increased CO2 levels from 1 in 3600 molecules to 1 in 2400.

Through out history when CO2 levels have gone up so too have temperatures and vice versa. All this extra C02 has caused 70% of Earth’s warming over the past 250 years.

CO2 is also that person that just wont leave the party when it’s over. It doesn’t like to disappear very quickly, in fact after a cloud of CO2 is emitted into our atmosphere it takes roughly 100 years for the first 40% to disappear. For that cloud of CO2 to be completely taken out of the atmosphere it can take up to 10,000 years.

SO, THE CO2 THAT YOU EMITTED IN THE CAR RIDE TO THE SHOPS TODAY WILL SEE YOUR LIFE COME AND GO AND YOUR CHILDREN’S AND THE NEXT 100 GENERATIONS AFTER THAT.



who is responsible?

 
 
 
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 whodunnit?

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There are a lot of factors that influence the climate of our planet. Here are just a few…

Suspect No. 1: The Sun

Earth’s orbit around the Sun is pretty wobbly and the Sun itself changes as it dims and brightens. History shows us that these changes in the sun have corresponded with temperature changes on Earth.

However in the past few decades the Sun has been cooling slightly. And as for the temperatures of Earth? Well they just keep getting hotter. Therefore solar activity is not causing our current global warming.

Suspect No. 2: Volcanoes

Those volcanoes do look pretty shifty! And they do burp out a whole load of Carbon Dioxide into the atmosphere. In fact Geologists have measured how much and it turns out that human activity releases about 100 times more CO2. The concentration of C02 has increased 40% since the Industrial Revolution in 1790.

STUDYING ICE CORES SHOWS US THAT CARBON DIOXIDE LEVELS IN THE ATMOSPHERE ARE CURRENTLY THE HIGHEST THEY HAVE BEEN IN ONE MILLION YEARS!

Suspect No. 3: Humans

We can measure the levels of different isotopes - or the different kinds of Carbon - that are in the atmosphere. Fossil fuels come mainly from old plants which prefer to use the lighter isotope Carbon-12 rather than the heavier Carbon-13.

When humans burn fossil fuels we can see that the percentage of C12 in the atmosphere increases.

impact on the ocean

 
 
 
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QUESTIONS

  • What percentage of a human body is water?

  • What percentage of the Earth’s surface is water?

  • Is your mind blown? 


Many of the effects of Climate Change are not happening on land, but in our ocean.

Since 1955 the ocean has absorb 90% of the Earth’s excess heat and it’s estimated it has absorbed half of the CO2 emissions since the Industrial Revolution (thanks ocean).

Water expands as it warms. Due to this the ocean is rising 2.5mm per year and since 1901 has risen 20cm overall.

C02 dissolves in the ocean and is converted into Carbonic Acid (H2C03) which raises the pH of the ocean, making the water more acidic. This is known as ocean acidification.

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Coral

Coral are only one example of thousands of species that are at risk due to climate change. Corals are made up out of calcium carbonate, but for calcium carbonate to be formed it needs to be just the right pH. If we continue to pour more CO2 into our atmosphere it only makes it harder for these corals to grow.

These acidic changes along with increasing water temperatures and pollution are putting strains on the symbiotic relationships that exist within healthy ecosystems. Coral reefs cover 0.1% of the ocean floor but are home to 1/4 of all ocean species. If we loose coral reefs we will loose the most diverse ecosystems on our planet.


DISCUSSION

How will Climate Change impact on humans?


ClimATE ACTION!

 
 
 
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GRAB A PENCIL

In your notebooks, complete this sentence: “Climate Change makes me feel…” 


What can I do?

Walk more, ride a bike, think about whether or not you actually need to get into the car to go 5 minutes down the road. Reduce your electricity by turning off lights, eat less meat, support businesses that support sustainability, educate others around you.

These are seemingly insignificant steps but if everybody contributed, we can change the way things are. Acting this way is also about the mentality that you nourish. When you learn to think in this way you are teaching yourself to be environmentally conscious - a mindset that is too often absent.

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sustainable energy

 
 
 
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Sustainable energy refers to creating energy in a way that does not depleting a natural resource - the resource is therefore renewable.

Some alternatives to using fossil fuels to generate electricity are:

Hydro

Hydroelectric power is generated using gravity. The movement of water downstream powers a generator that creates electricity.

Wind

Wind turbines are very similar except, they use wind to power their generators.

Geothermal

Geothermal energy is harvested by digging into the Earth’s crust until we reach high temperature lava. Countries such as Iceland and the Philippines are located on thinner crust and are able to harness this energy more easily.

The Sun, photovoltaic cells & thermal energy

Conventional solar power works by converting the Sun’s light energy (or photons) into electricity but recently Australian scientists - here in Newcastle! - have been able to start using the Sun’s heat energy by focusing large mirrors towards a centre tower. Inside this centre tower are a series of tubes that carry steam. When the steam is heated even further by the Sun’s energy, it turns into a state known as supercritical steam. This supercritical steam can then be used to power generators that create electricity at the same rate fossil fuel generators create electricity - but for a fraction of the cost!

The Ocean

The ocean is full of energy! Most of which is generated by the wind. Energy can neither be created nor destroyed and when the wind’s energy is transferred into a liquid medium - such as the ocean - it becomes far more predictable and visual.

There are many different ways water moves around the ocean and humans can harness the energy of each process.

Tidal

The tide comes in and out. It is just as reliable as the Sun coming up*! Tides are the result of the Moon’s gravitational pull. By designing two-way rotating turbines it would be very simple to harness this water movement. This method does require tides of more than 5 metres to be feasible, but this is no problem in countries closer to the equator.

*Note: the Sun does not really “come up”.

Wave

Waves pass through regularly and are three times more predictable than moving air. By harnessing their directional movement in generators we can also produce electricity.

Currents

Just like tidal and wave movement, currents can be used to harness the physical movement of water. 

Thermal

Harnessing the thermal energy of the ocean is a relatively new concept and works by passing warm surface water (over 20 degrees celsius) through a station which then warms an extremely volatile liquid. As this liquid evaporates it creates high pressure that is able to turn a turbine which powers a generator that creates electricity.


QUIZ TIME!

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