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September 20, 2015 | by  | in Science |
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Is it getting hot in here?

A quick guide to all the climate change “hot words” that are constantly used, but barely ever explained. Apparently we’re all supposed to just happen to know this shit.

When I was a kid, every time I heard people mention “greenhouse gases” and the “greenhouse effect”, I thought the problem was harmful emissions from the greenhouses people used for growing plants. Fast-forward a few years, and I found myself taking a university paper on energy resources and use, and soon discovered that amidst the media outlet of the global warming debates, the growing use of climate change as a political weapon, and the financial gain for businesses by labelling their products “green”, not many people were taking the time to explain what the fuck it all meant.

The Greenhouse Effect and Greenhouse Gases

In some ways, you can think of the sun as a giant ball of energy. Because of space and the universe and big things happening, it sends a whole bunch of energy to Earth, mostly coming in the forms of heat energy and light energy.

When this hits the earth, the land and water on Earth’s surface absorbs a lot of the energy, while some of it is reflected right off the surface—like shining a light on a mirror and having it reflect back off.

Of this rejected energy, some of it goes back into space. A good chunk of it, however, gets trapped in a layer of the atmosphere made up of gases that trap heat, like a blanket around the earth. Because Earth absorbs energy, without the blanket to trap some, above the earth’s surface would actually be below freezing point.

The large amounts of anthropogenic (manmade) emissions produced are added to this “blanket”, making it thicker and thicker, so less heat can escape. This is the greenhouse effect.

To put it another way, think of a baked potato wrapped in tinfoil. The potato represents earth and the tinfoil is our blanket of atmospheric greenhouse. The heat comes in from the oven, and the potato absorbs some of it, but the rest is bounced off. The shiny tinfoil traps some of this heat, and sends it back to the potato, to keep it warmer.

In case you hadn’t guessed, the gases that make up this atmospheric layer around the planet are the greenhouse gases, like nitrous oxide, methane, and carbon dioxide.

Weather and Climate

Weather is the current, observable state of the atmosphere. If you look outside and it’s hot, cold, sunny, rainy, whatever it is—that’s the weather.

The climate is the average weather in a particular location over a period of time (usually measured in 30-year periods). This “average weather” can be measured in terms of many different features of the climate, like the average temperature or average rainfall over the time period. When people talk about the Earth’s climate, it’s the average of these features everywhere in the world. That’s why when talking about Earth’s average temperature, it may sound pretty high for a place like Antarctica, but rather underwhelming for the tropics.

Global Warming and Climate Change

While the phrases are often used interchangeably, climate change and global warming are not the same thing.

Global warming can be defined as the temperature increase produced by adding greenhouse gases to the atmosphere.

Climate change is a change in the typical climate of a location. This change in typical climate must be sustained over a long period of time. Climate change can be caused by global warming.

Why do people go on about carbon emissions?

Thinking back to greenhouse gases, I mentioned some of the key players:

  • Methane—a primary component of natural gas used for fuel, and also a byproduct of the cattle digestive system in agricultural practices; you may remember the 2003 “fart tax” proposal.
  • Nitrous Oxide—a byproduct generated from agricultural fertiliser production and use.
  • Carbon dioxide—the greenhouse gas of most immediate concern, largely produced by our excessive burning of fossil fuels.

While carbon dioxide isn’t the most heat-trapping gas, it’s present in the highest concentration in our atmosphere and has a long atmospheric lifetime of up to 200 years. Meaning the carbon dioxide you released driving to university today will still be chilling up in Earth’s gas blanket, glaring at your grandchildren.

The Carbon Cycle

All living things are made of carbon (and many non-living things, like rocks and minerals, have a large carbon component too). Carbon dioxide (CO2) is formed when certain reactions cause oxygen molecules to attach to carbon molecules.

The carbon cycle refers to the long-term and short-term natural processes in which carbon and CO2 is continuously exchanged between parts of the climate system. Short-term, CO2 is constantly being exchanged between plants, trees, animals, the atmosphere, and the oceans—like when we breathe CO2 out as waste, or when plants consume it to feed themselves.  

Long-term, 99.9 per cent of carbon is stored in reservoirs in rocks and as fossil fuels. This carbon is slowly released through natural processes such as rock erosion, resulting in carbon movement into the ocean and atmosphere. Most of our oil reserves are the result of plant and animal remains being buried in sediment millions of years ago, then being subject to heat and pressure over time. By extracting and burning these fossil fuels, we’re releasing excess carbon from long-term storage reservoirs at increasingly rates—much faster than it can be returned to storage.

For millions of years, Earth has tightly regulated the levels of atmospheric versus stored carbon dioxide, encapsulating the natural carbon cycle. However, carbon dioxide emissions have dramatically increased since the industrial era, destabilising this natural cycle.

How do we know the problem is manmade?

Through ice core extraction, we’ve been able to analyse the gaseous compositions of air bubbles trapped in ice formed as far back as 800,000 years ago. Such research has allowed us to trace changing atmospheric gas levels, showing that atmospheric concentrations of greenhouse gases were largely consistent until the industrial era, where they began to rise sharply. Today, atmospheric CO2 concentrations are nearly 40 per cent higher than preindustrial levels.

Sea Level RisingMore than meets the eye, you see?

Rising temperatures can cause sea level rises in two key ways: the expansion of water as it heats, and melting of land-based ice sheets and glaciers—both of which are implicated in a range of unfavorable climatic repercussions.

Rising sea levels can push cause seawater further inland—contaminating our soils, causing destructive erosion, and jeopardising the habitats of fish, birds, and plants. Higher sea levels can also increase intensity of powerful storms, and bring them further inland. Even a rise of just one metre puts coastal habitats at high risk of devastation.

When Weather Gets EXTREME

The weather system is filled with complex interactions, and any adjustment can have a range of repercussions. Observable weather events occur primarily from air pressure differences between two locations, which can be caused by variations in air temperature and air moisture content. For example, the angle of the sun can influence pressure contrasts. As the sun is angled more directly at the tropics, locations further from the sun receive less direct sunlight and are, on average, cooler. The contrasting temperature can influence air pressure.

Rising temperatures can cause increased evapotranspiration—the total water evaporating from plants, soils, and water bodies, influencing the intensity and frequency of droughts. Conversely, a warmer atmosphere can hold more water vapour, which increases risk of extreme rainfall events.

For Fuck’s Sake, No, Colder Winters Don’t Disprove Global Warming

While it sounds counterintuitive, rising average temperatures can in fact influence the intensity of our winter seasons in both temperature and storm incidences. There are multiple weather systems in place that account for temperature variations throughout the seasons, and destabilisation of any of these can result in extreme temperature events. For example, destabilisation of polar vortexes. These are large pockets of very cold air, positioned above the North and South Poles. As global temperature rises, snow cover and ice coverage decrease and the ocean temperature increases, yielding a subsequent increase in evaporation and transpiration, altering pressure and temperature gradients across these polar vortexes and destabilising them. When strong and stable, the vortexes contain their cold air. Weakening of them can result in some of the freezing air breaking out and travelling into regions not accustomed to such cold.

Ocean AcidificationIt’s not as trippy as it sounds

As carbon dioxide emissions continue to offset the natural carbon cycle, the excess carbon is stored both in the atmosphere and in the ocean. Ocean absorption of CO2 is a natural part of the normal carbon cycle, however the rate of CO2 being absorbed is causing the ocean water to become more acidic. This is because of a natural reaction between CO2 and seawater. CO2 reacts with water molecules, and forms a weak acid called carbonic acid. Excess CO2 absorption results in higher levels of acidity, which can completely destroy marine habitats.

Well, that sucks then.

Yes, yes it does—but fortunately, experts are ensuring us that it’s not too late to, you know, fix the planet and shit. Basically, after hearing all the ads telling us to have shorter showers and walk more and actively save energy, rather than rolling your eyes because “yes, I KNOW ALREADY”—actually try to adjust your habits. Put the car keys away and save on the fuel bill. And next time you’re panting your way up Devon Street in the rain, when it’s easy to pity yourself and wish you were driving, just catch your reflection in the windows of the poor people on display that keep forgetting to close their curtains and remind yourself—you’re Captain Frickin’ Planet.

When all is said and done, I don’t see why we don’t steal some climate terminology for the 420 world. Goodbye hotboxing, hello greenhouse gassing.

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