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It’s all about balance. Too much CO2 for Earth to process.

Argument 1. “The climate has changed before throughout history – this is just part of the natural cycle and doesn’t have anything to do with humans”.

The Science: There have been several times that the Earth’s climate has warmed, each time due to increases in greenhouse gas emissions and each time proved highly destructive for life, caused mass extinctions, ocean acidification and rising sea levels.

So we KNOW that changes in greenhouse gases have a direct relationship on changes to the Earth’s climate. An increase in the gases, primarily CO₂ (carbon dioxide) and CH₄ (methane) heat the Earth, while a reduction in the gases sees the temperature drop. Before the onset of anthropogenic (caused by humans) emissions, these increases came from natural sources, such as massive volcanic activity on our young planet, but we don’t experience that now.

In the Eocene and Cretaceous periods  there were high levels of CO₂, but life flourished as the amounts of greenhouse gases were in balance with the carbon in the oceans. However, over the past 200 years, humans have emmitted massive amounts of CO₂ at a rate faster than can be balanced out.

The climate does change naturally due to the Milankovich cycles, which determine the angle of the Earth as it travels around the sun and has produced warm (interglacial) and cold (glacial) periods. But these are cycles are not related to greenhouse gases and we can relate them to the the planet’s transitional path.

Therefore: The current climate change is due to human activity by producing more greenhouse gases than our planet can handle.

Argument 2. “Periods in the past have been warmer than today – this shows the climate warmed even before humans started emitting greenhouse gases”

The Science: People here are probably referring to the Medieval Warm Period (950-1250AD). There is no debate that it occurred, but the causes for it are contested. It is generally agreed that the Warm Period was the result of a number of climate systems, including:

• changes in ice albedo (reflectiveness)
• changes in vegetation
• seasonal shifts
• a Dansgaard-Oeschger event (warming possibly due to changes in Atlantic ocean circulation)
• interaction between the NAO (North Atlantic Oscillation) and the La Nina phase of ENSO
• increase in solar radiation
• lack of ‘cooling’ volcanic eruptions (produces methane, but particles blot out sun)

Temperature reconstructions of the Medieval Warm Period show that average SST (sea surface temperatures) were within 1°C of current temperatures, but the latest IPCC report predicts a massive increase of sea temperatures, up to 6.4°C by 2100. Yikes!

In 2009, an answer was found in the annual growth rings of Moroccan atlas cedar trees and the stalagmites that grow in a Scottish cave beneath a peat bog. What they showed is just how wet it had been in these regions during the Medieveal Warm Period.

Morocco is affected by a strong high pressure system called the ‘Azores High’ whilst Scotland is affected by a low pressure system called the ‘Icelandic Low’. The pressure difference between the two meant there was a very strong positive North Atlantic Oscillation (NAO). This is an ocean current that drives warm winds from the Atlantic over Europe….so it got pretty warm at that time!

Now, there’s a bit more to this research, but it involves even more acronyms…and you’ve probably suffered enough. But what they did work out, was that Medieval Warm period was regionalised, meaning that it warmed in some areas, instead of producing a general world-wide warming.

Therefore: There was a previous period of warming, but we can prove what caused it, and it wasn’t humans. We can also prove that climate science is very complex and involves more anacronyms than is sensible!

Argument 3. “The sun is causing global warming”

The Science: This argument goes along the lines that there are an increasing number of sunspots, which coincide with periods of high solar activity and therefore the spots must contribute to warming the planet  – just like in the apocalyptic film ‘2012′.

This is a direct example of correlation does not equal causation. The sun is our dominant source of atmospheric heat, but has actually cooled slightly recently. This is occurring whilst global temperatures are increasing, so it doesn’t make sense to anyone that the sun could be causing global warming.  Climate deniers have cherry picked the data where increases in sun spots and temperature correlate, and ignore other periods where they don’t match up.

Earth getting warmer – Sun getting cooler.

Therefore: No, the sun is definitely not causing global warming as the sun is actually cooking slightly.…awkward.

Argument 4. “Scientists don’t agree on climate change”

This argument is one circulated by the mass media and often sponsored by organisations who benefit by perpetuating the argument. The ‘Petition Project’ is an example of this. It was set-up by a small group of scientists who aim for ‘health and longevity’ (reducing food intake cures cancer etc).

They claim to have 31 000 signatures of American scientists who don’t support the idea of human-caused climate change. Now at first, this might sound startling, but they’re pretty liberal with who they include as ‘scientists’. In fact most are engineers, they also include food and computer scientists, who lets face it, don’t exactly have a curriculum full of climate studies.  The only scientists with enough knowledge on the matter to make a legitimate statement of fact, are climate scientists…of which they had just 39, and of course, it’s impossible to check and validate these entries.

However, even if we did believe that the 31,000 were scientists with climate knowledge, compared to the number of those with graduate degrees in these areas, this means that only a minute ~0.3% of scientists in the US don’t believe climate change is caused by human industry. Awkward!

In reality, 97% of published climate science research papers agree that climate change is real and primarily caused by humans, specifically the burning of fossil fuels. Remember that there are scientists producing papers on climate change who are sponsored by climate-denier organisations.  These papers come under great scrutiny of peer review, meaning that it has been determined as legitimate by many qualified and independant scientists.

Therefore: 97% of scientists agree that climate change is produced by man. The 3% are possibly employed by climate-denier organisations and need to adhere to those sentiments, or have not read the research papers on climate change.

Check out http://theconsensusproject.com/ for more information on how climate scientists agree on climate change and this hilarious segment on Last Week Tonight:

Argument 5. “The climate is cooling, not warming”

The Earth switches between cold (glacial) and warm (interglacial) periods. Currently, we’re about 18,000 years into an interglacial period and heading towards the next cold snap. However, we’ve a while to wait as this change to cooler climate will be occurring in thousands of years, but the focus on climate change looks at the present and into the next hundred years.

Thorough examinations of the Earth’s past and current climate show evidence of global warming; air temperatures (over land and sea) are increasing, snow cover is decreasing, ice is melting, sea levels rising and sea surface temperatures increasing. Sceptics tend to take selected evidence where cold records are being broken in comparison to the recent past, whereas heat records are being set over all time. The evidence is overwhelming.

Therefore: The climate is due to cool in thousands of years time…but right now, all evidence proves the Earth is warming.

Argument 6. “Climate models are unreliable”

Climate models are incredibly complex mathematical representations that consider all interactions between the atmosphere, oceans, surfaces and incoming solar radiation….can you imagine the massive amounts of data that produces! Models use data recorded from the past and present to project trends about the future (not specific events).

These models are heavily tested by a process called ‘Hindcasting’, where the models use data from previous times to see if they can accurately predict trends. Models which incorporate additional amounts of CO₂ successfully map current trends of warming, whereas those who do not include extra CO₂ don’t fit the data readings – this shows that CO₂ is a major contributor to climate change.

Models have successfully predicted the climate recovery after the Mt. Pinatubo eruption, where large amounts of gas and aerosols (tiny particles in the atmosphere) cooled the climate. They have also correctly predicted warming over the Arctic areas.

One of the main arguments against climate models is that they take the worst-case scenario and over-exaggerate things, but so far actual data is proving closer to the ‘worst case scenarios’ than milder predictions. Models are constantly being improved with new satellite data and climate scientists constantly investigate ‘uncertainties’ in their models, but so far they’re doing a pretty good job.

For example, this is a model based on sea level rise – it’s clear to see just how well the predictions of the model fit with data from the tide gauge. It’s more than a bit scary that the actual observations fit the upper ‘worst case scenario’ of IPCC (Intergovernmental Panel on Climate Change) projections.

Therefore: Climate models are proving accurate…and getting better.

Argument 7. “The ‘hockey stick’ is wrong”

Not so Jolly Hockey Sticks!

The ‘hockey stick’ refers to the sharp incline in global temperature recordings in the past 100 years in comparison the previous 1000 years – the shape looks a bit like a hockey stick (well it does to climate scientists!). These readings were based off ‘proxies’ (ie, not direct climate data like atmospheric samples) such as corals, stalagmites, tree rings, boreholes and ice cores.

Climate sceptics determine the trend as nonsense and full of errors, where in actual fact the data from the proxies proved that the climate cooled over the past 1000 years and took a sharp upturn in the 20^th century as temperatures continually broke heat records.

Studies confirm the original hockey stick model; that the climate dramatically warmed after 1920 (when the effects of the Industrial Revolution kicked in).

Downwards slant, then sharp upturn = the hockey stick

Therefore: The ‘Hockey Stick’ model is jolly hockeysticks correct – the climate suddenly got hotter

Argument 8. “It’s been really cold – so much for global warming”

There is a difference between weather and climate. Weather refers to atmospheric conditions over a short period of time, whereas climate looks at trends which develop over many years.  Long-term trends over the past 100 years show that the climate is warming significantly.

Temperature fluctuates all the time on a seasonal basis and especially with the effects of the ENSO (El Nino Southern Oscillation). Climate scientists read the long-term trends from temperature graphs and do not take into account short-term temperature fluctuations. It’s easy to manipulate temperature readings to present data to show the climate cooling by pulling out data ofs hort durations – climate sceptics generally cherry-pick data to portray the climate as cooling in this respect.

However, the fantastic thing about science is that you can’t argue with facts. NASA data shows since 1998, the temperature has been the hottest in all recorded temperature history, and that a strong and significant warming trend is evident over all data records.

Definitive global temperature rise

Therefore: Global temperatures are steadily warming, but there are still seasonal and local variations.

Argument 9. “Human emissions are insignificant compared to natural emissions”

The Earth functions with a natural carbon cycle that transports carbon around the environment between the land, sea and atmosphere in sources and sinks. This cycle is naturally kept in balance, but humans upset this balance by continually adding CO₂ without removing any.

A build-up of gas is never good!

Looking at gases trapped in air bubbles in ice cores, we know that carbon dioxide levels have remained about 180-300 ppm for the past half a million years. However, in recent centuries as humans started burning fossil fuels, carbon dioxide levels have risen to about 380ppm.

The natural carbon cycle emits and absorbs massive amounts of CO₂ (about 750 giga-tonnes), in comparison to human emissions which are about 29 gigatonnes. So…what’s the problem? About 40% of extra CO₂ emitted is absorbed by the oceans, which are a massive carbon sink. The rest hangs around in the atmosphere and contributes to the greenhouse effect because the carbon cycle can’t process all this extra CO₂ – humans are upsetting the carbon cycle. As a result, CO₂ levels are now the highest they’ve ever been in 15 -20 million years.

Therefore: The amount of CO2 we produce is more than our Earth can absorb. It’s as simple as that. We MUST massively reduce our CO2 emissions.

Argument 10. “But…water vapour is the biggest greenhouse gas”

Water vapour is technically the most dominant greenhouse gas. There’s an awful lot of water on our planet, when temperatures warm, water evaporates (converts to a gas). You can see some water vapour in the form of clouds.

Fluffy white cloud turns eco-killer!

You’d have noticed that if there’s a lot of cloud cover at night, it’s not as cold as if it was a clear sky. This is because the clouds act as a sort of blanket to our lower atmosphere, trapping the warm air in. But if you add more CO2 and other greenhouse gases than our Earth can handle, the global warming that is produced, causes more heat, which means more water evaporates into vapour, which means even more heat is trapped in our atmosphere. This is called a positive feedback system. 

The IPCC doesn’t really classify water vapour as a greenhouse gas because it is part of this system, and not just a forcing agent. But we do know that any increase in temperatures produced by CO2, can dramatically snowball once enough water vapour is produced as not only will it further increase global temperatures, but it also has the potential to affect weather patterns.

Therefore: It is….and it isn’t. Either way, the more CO2 and methane we produce, the more water vapour will be in our atmosphere to further heat our planet – so it’s really important we dramatically reduce our CO2 emissions.

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Having said that, there is an awful lot that scientists DO know and can prove. Unfortunately, there are many who choose to ignore the science for various reasons. We’re guessing these include:

1.  Think they’re clever: Skeptics feel special because they believe they’re more intelligent than the general public and can see through stated facts. This arrogance is actually built upon insecurity; they try to puff themselves up to be something they are not. Most skeptics are generally just repeating other skeptics viewpoints and rarely check things out for themselves. How clever does this make them?

2. Political self preservation: Stating that climate change is not happening, or is not man-made, suits some people politically. Politicians have to stick to whatever their party believe in. The same goes for those working in organisations where there is a climate (ha ha!) of skeptism towards man-made climate change.

3. Self-interest: They either work for, or benefit in some way from the fossil fuel industries or those that produce most emmissions (gas, oil, electricity, mining, manufacturing). These organisations can afford, through media campaigns, to discredit the scientists involved, dispute their findings and create controversy by promoting claims that contradicted scientific research.

4. Cowardly Custards: They are frightened of change. Climate Change is scary. Like a child who keeps repeating ‘there’s no such things as ghosts’ when feeling scared in the dark, well, this is the Climate Change version of that. For some, this behaviour is easier than facing the reality of change.

5. Plonkers! Let’s face it, when nearly every scientist on the planet says something is real and has the evidence to prove it, you’d have to be a bit lacking in grey matter to disagree.

6. Fence Sitters: To be fair, there are some scientists who whilst they agree that climate change is happening and caused by man, they don’t agree with the data, or rather the methods used to collect the data – they believe the models are too simplistic. They also might not believe in the proposed remedies, or simply think we should just put our money towards more immediate issues, such as malaria, AIDS etc.

Here’s what real climate scientists say…in rap!

How to spot a climate denier? You might want to remember these facts in case you come across a climate denier. Use our handy guide to spot them.

Known climate deniers….add your own to this; there’s lots of ’em out there.

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Average global temperatures had been steadily rising, then after a record high in 1998, global warming stalled and many thought this was proof that global warming was just a natural climate cycle and global warming due to greenhouse emissions was just a big fat silly lie.

This pause in global warming is called the Climate Hiatus. The climate hiatus is thought to be entering its 16th year; temperatures haven’t risen significantly since 1998 despite heavily increasing amounts of greenhouse gases. Because of this, climate models have been difficult to adjust and currently don’t match previous data and temperature predictions. Climate models anticipated that the Earth would warm at 0.21°C per decade from 1998-2012, but instead it’s been warming at 0.04°C per decade.

When the climate just doesn’t match the model…

Some scientists believed the hiatus was due to volcanoes, pollution from China, atmospheric aerosols and even the Sun as potential culprits. But climate scientists were worried as they knew that the effects of greenhouse gas emissions had to be building up somewhere.

During 1998, the year that broke temperature records, the Earth was undergoing an El Nino period, which then switched to a La Nina period. During La Nina, sea surface temperatures drop releasing heat into the atmosphere. This cooling of the oceans may have changed the normally warm Pacific region into a cooler state,  which then balanced out the warming caused by greenhouse gases. This climate system is called the Pacific Decadal Oscillation. Climate scientists predict that in the coming years, this will switch back and the Earth will experience very rapid warming.

There’s more; the Sun waxes and wanes on an 11 year cycle, and around the climate hiatus period the sun entered a prolonged lull in the weakest solar maximum in a century. This not only helps explain the climate hiatus, but also why some climate models have over-estimated global warming as they factored in a stronger solar output.  Particles released by volcanoes, such as ash, reflect sunlight back into space and an increase in these can result in a mass cooling effect. This was seen after the volcano, Mount Pinatubo erupted in 1991 lowering global temperatures about 0.5°C. An increase in stratospheric aerosol particles are another factor in keeping the Earth cool.

An important part of understanding the climate hiatus is the Pacific Decadal Oscillation (PDO). Different phases of its cycle either favours the atmosphere-warming El Nino (positive phase), or the cooling La Nina (negative phase). These phases switch around every 15-30 years. In 2011, researches at the National Centre for Atmospheric Research (NCAR) led by Gerald Meehl showed that when they took into consideration the PDO when constructing climate models, it showed decadal breaks in global warming…which sounds an awful lot like the climate hiatus we’re experiencing!

The research team flipped the PDO to positive, which showed decades of rapid warming. We’re currently in the negative phase, so this gives an idea that when the PDO flips back to negative, we’re headed for rapid warming.

Another team showed similar results by incorporating tropical trade winds into models, which help promote cool water to upwell in the eastern Pacific equatorial region in the La Nina period. In the extreme La Nina of 1998, these winds helped push the ocean into the cold phase of the PDO, which counteracted global warming caused by our increasing greenhouse gas emissions.

However, here’s the twist; a study recently published in the Royal Meteorological Society suggests that the climate hiatus might be more due to incomplete data than aerosols, solar flares or polar jet streams. Oops! Apparently the HadCRUT4 model only considers data from 84% of the globe. The remaining 16% are basically tricky to get to places. Unfortunately, this includes the poles and Africa. Kind of important places when it comes to climate change. Which is why the authors, Kevin Cowtan and Robert Way, used data from satellites to ‘fill-in the gaps’.

What they found is, to cut a long story short, that there hasn’t been a climate hiatus at all. In fact the actual rate of global warming, 0.12 °C per decade, nicely ties in with the UN’s Intergovernmental Panel on Climate Change predictions.

There…problem solved.

Background image: CorbisCorporation

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Sad polar bear

In every article about climate change, it’s pretty much guaranteed you’ll see a picture of a sad polar bear balancing on a small piece of floating ice….see right for ours.

Climate research clearly proves that polar ice (including glaciers, pack-ice and glaciers) are melting. Also, the sea level is rising and snow cover is decreasing…but why is this all happening?

The science behind melting ice caps.

So Elsa managed to unfreeze her icy home town…but this isn’t exactly the case in the poles. All the finger-pointing comes back to yet again greenhouse gases and how they trap heat from the sun in the Earth’s atmosphere. Check out our article on climate change for the low down on how this works.

It all comes down to something called ‘albedo’. No, it’s not a fancy Italian cheese, it’s the fraction of solar energy (which is short-wave) that’s reflected from the Earth back into space. Essentially, it’s how ‘reflective’ the Earth’s surface is.

Some surfaces are more reflective than others – paler surfaces have a high albedo and will reflect light, whereas something darker has a low albedo and will absorb heat more. This is why black tarmac roads get really hot in the summer (as you’d know if you attempt to go barefoot in Summer).

Snow has a very high albedo so it reflects approximately 95% of sunlight (so its albedo is 0.95). Water reflects less sunlight – about 10% (its albedo is 0.10). Hence, the less a surface reflects the sun’s radiation, the more it absorbs and is therefore easily heated-up.

Arctic Sea Ice melt contributes to climate change by reducing the Earth’s overall reflectivity

Great…so how does this fit into climate change?

As temperatures  rise with global warming, more ice (high albedo) is melted into water (low albedo). So there’s more water to heat-up, which in-turn, melts more ice…and so on. This is a positive feedback climate process. As more and more ice melts, so the sea level rises causing flooding and loss of habitat for animal life which live on the polar ice, such as Arctic fox and polar bears.

Polar ice sheets are melting approximately 9% each decade, and could have ice-free in summers by the end of the century. The largest single block of ice in the Arctic (the Ward Hunt Ice Shelf) has been around for about 3000 years and began cracking in 2000 – within two years, it’s completely split in two and is breaking apart.

Albedo Positive Feedback Loop

It’s not just the poles who are at risk because of albedo. Urban environments such as cities experience something called the ‘urban heat island effect’. Highly developed areas tend to have less vegetation and more infrastructure with darker surfaces (asphalt roads, buildings, etc.) which absorb and trap heat, especially during the summer months.

This causes problems as people in cities are at a greater risk for heat-related illnesses. The good news is that we can use albedo to our advantage- by building paler buildings and planting more vegetation with a higher albedo to reflect heat back into space.

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When we talk about climate change, pollution or the greenhouse effect, we tend to first look to the changes that our atmosphere and land will experience. But perhaps a bigger threat is brewing in our oceans.

Marine ecosystems are vulnerable to even the smallest changes and whilst a sturdy group of scientists and eco-activists are trying to draw our attention to these issues, to a certain extent, their cries are falling on deaf ears.

So is ocean acidification caused by the oceans becoming more acidic? Well, durrrr…..yes, of course. It’s all down to carbon dioxide – CO2.  The concentration of CO2 in our atmosphere is 30% higher than 150 years ago, which was around the time that man turned to burning whacking great amounts of coal, otherwise known as the ‘industrial revolution’. This is because we burn fossil fuels, like coal and oil, for our heating, transport and industries.

The oceans act like a big sponge and are great at absorbing gases through process called ‘the ocean carbon cycle’, CO2 gets into the sea water as it’s dissolvable. In fact of all the CO2 emitted into our atmosphere, 25% is absorbed by plants and trees, and another 25% is taken up by our oceans. Most of the remaining 50% remains in the atmosphere. So far, half of all the CO2 produced by man since the Industrial Revolution has been absorbed by our oceans.

When CO2 is combined with salt water it produces carbonic acid – H2CO3. Carbonic acid is essentially a solution of carbon dioxide…yup, a bit like Coke. It’s a weak acid made of two salts:
1. Carbonates – naturally occurs in caves, disolving limestone. Think of all the ‘use Coke to clean your car’ videos.

2. Bicarbonates. You’ll find calcium bicarbonate in many limestone features such as stalactites and stalagmites.

Interestingly, this process reduces the capacity of the ocean to absorb CO2. Good for our oceans…but not for our atmosphere or land plants as all this CO2 has to go somewhere.

CO2 plus H2O = carbonate, which also produces bicarbonate = ocean is screwed

All this extra carbon dioxide has caused an increase in PH of about 0.1 from pre-industrial levels. It’s estimated that by the end of this century, surface waters could be nearly 150% more acidic; a level not seen in over 20 million years.  Now 0.1 might sound much, but it represents a 30% increase in acidity at the oceansurface. Plus, our marine environments are incredibly sensitive. This process and state is called ocean acidification.

This process lowers the pH (increases acidity) and therefore affects the marine organisms that need calcium-carbonate to make their shells and skeletons. this is because this chemical reaction ‘uses up’ the calcium carbonate…which is bad news for  these types of marine life (e.g: coral and shellfish) who may no longer be able to form shells to protect them. Already marine biologists are finding that some marine species are not able to properly grow shells.

Sea urchins are needed by coral to clean them of algae growths, but biologists are finding many have mis-shapen shells and spines and are growing too slowly. Pteropods are teeny marine snails known as the potato chips of the sea – this is because everything eats them. But their thin shells will disolve and all marine life dependant on eating them, will crash.

Ocean Carbon Cycle producing Acidification

Marine life is affected in other ways –

• Ocean acidification impares the ability to absorb oxygen, so marine life that relies on bursts of speed, such as squid, will not escape prey, or catch food.
•  Egg larvea and sperm will not survive the acidic environment
•  Some fish experience a reduced sense of ‘smell’ in acidic conditions causing eratic and risky behaviour resulting in x 9 times more fish dying
•  Some marine species, such as brittle stars, lose muscle mass in adicidic conditions

 Right now coral is particularly at risk. The Australian Great Barrier Reef may be completely destroyed by 2050 due in part to ocean acidification. This is because acidic conditions reduce the growth rate of coral and this significantly impacts the coral as it needs to continually grow to combat ‘bioerosion’ from reef-dwelling critters that constantly break apart pieces of coral for food or habitat construction, so the coral have to grow quickly to counteract this.

Nom nom…coral-chomping fish.

An increase in acidity means that new coral formed is weaker and will not survive in harsh conditions. This leads to a decrease in biodiversity, where only the hardier coral species will survive. Biodiversity is a term you’ll often hear thrown around when talking about conservation. Nature is a delicate balance and it’s important to protect our natural environments so that balance can be maintained. Removing just one species can have dire results for dozens that may rely on it.

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Map showing temperature change in Australia since 1910

Image: IPCC: Note how the amount of CO2 is much higher than had been originally predicted (by thin black line)

Everything on our planet is interelated – what happens to our atmosphere affects our land, and what happens to our land affects our oceans and so on.  We depend on our environments for the food to feed us, our fuel to heat and transport us…and everything depends on water. These necessities for life are also essential for our economic survival. The effects of climate change will be far reaching, but the most immediate effects will be seen in our natural environments. Here’s the most obvious ones:

Global Climate change produces visible and significant changes to our environment but will affect different places around the globe in varying ways.

The IPCC (Inter-governmental Panel on Climate Change) states that the way that climate change will affect individual regions will vary over time and will be dependant on the ability of different societal and environmental systems to mitigate or adapt to change. What this means is that some plants and animals will be able to cope with the change in the environment where they live. Also, some countries will be more adept and motivated to invest money into projects which may reduce the effects of climate change.

Climate scientists cannot predict the future with 100% certainty. Our planet has never been in this situation before, so they have nothing to compare against. However, using models (complex computer programs) and data recordings, they have a pretty good idea of what to expect. So far, the outlook isn’t good.

Where do you live? How will our changing climate effects you?
(These are the regional impacts of global change forecast by the IPCC.)

Prepare for increased inland flash floods, more frequent coastal flooding with sea level rise. Increased erosion from storms meaning a reduction of crop productivity in Southern Europe (from a loss of nutrient-rich top soil). Glacial retreat in mountainous areas, reduced snow cover (goodbye ski season) and extensive species losses.

Loss of snow in western mountains, increase in rain-fed agricultural yields (by 5-20%). More frequent and intense heat waves in cities.

Forests drying out to become savannahs in Eastern Amazonia resulting in a loss of biodiversity (also due to human deforestation activities). Significant changes in water availability for human use in consumption, agriculture and generating energy.

Increase in dry conditions- the IPCC estimates that by 2020, approximately 75 – 250 million people will be exposed to increased water stress. Agricultural yields that rely on rainfall will reduce by up to 50% in some regions – access to food and water will be compromised.

Access to freshwater will decrease in Central, South, East and Southeast Asia by 2050, coastal areas will be at risk to increased flooding. This carries issues of increased disease associated with floods and freshwater droughts in some regions.

Increase in drought, and an increase in frequency and intensity of bushfires, extreme heat waves. Sea level rise threatens coastal societies and environments, and increasing temperatures lead to more mass coral bleaching events in the Great Barrier Reef. Climate scientists predict there will be fewer cyclones, but they will be more intense.

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The first Irish famine was caused by an intense prolonged frost

Throughout history, the Earth’s climate naturally fluctuates due to Milankovich cycles. The climate switches from cool (glacial) to warm (interglacial) periods which last  between 15 000 to 20 000 years.

 The last ice age was the dubbed the ‘Little Ice Age’ of 1400 to 1860. Although temperature only dipped globally about 0.5 C, it caused some serious problems for humans throughout time such as the demise of medieval Viking colonies in Greenland, where the cold weather meant their lifestyle became more Inuit than Viking,  and the Irish Famine of 1740 to 1741 where mild Winters were followed by an intense frost which killed crops, froze lakes solid killing fish and people were forced to burn firewood that only lasted a few weeks leaving them to freeze to death in their beds.

Right now, we’re in an interglacial period about 18 000 years in, heading for another ice age a few thousand years. In fact, there were fears about global cooling as we approach the next ice age, but these fears have rapidly changed to those about the warming of our climate.

There has been natural fluctuations in temperature – but nothing like what we’re about to experience.

In the last couple of hundred years, temperatures have been rising abnormally, due to the release of large amounts of greenhouse gases which trap more solar radiation within the Earth’s atmosphere and increase temperatures. These gases include carbon dioxide, water vapour, nitrous oxides, methane and ozone. These arise both naturally and from anthropogenic (produced by humans) emissions.

Natural greenhouse gas emissions arise from plant and animal processes, marsh and swamp lands which emit methane and volcanoes, which emit such large amounts of greenhouse gases and aerosols that they actually cool the climate – (see volcanoes and aerosols).

Greenhouse gases are also emitted by humans (anthropogenic emissions). Since the start of the late 18th century when the  Industrial Revolution got underway, humans started burning massive amounts of fossil fuels, such as coal and oil, which emit large quantities of CO2 into the atmosphere.

Fossil fuels have been burnt heavily since the Industrial Revolution of 1780

The effect of this was first noticed in the 1890s by people such as Swedish chemist Svante Arrhenius, who calculated that a doubling of atmospheric CO
2 would cause the climate to warm by 5 to 6 degrees Celsius. (‘proof of climate change’). However, we’ve done little since then to reduce the amount of CO2 we produce, even though the voices of climate scientists is now a deafening roar. They are falling on the deaf ears of our politicians in countries around the world (see, countries embracing alternative energies)

The sun emits short-wave radiation to the Earth, which is scattered, absorbed and reflected by the ground, particles and gases in the atmosphere and clouds. Radiation that is reflected from the Earth’s surface is long wave radiation. Short-wave radiation can be easily transmitted through the Earth’s atmosphere, but long-wave radiation is easily absorbed by carbon dioxide, and so the heat becomes trapped underneath the ozone layer and cannot escape out into space. This thickens the ozone layer which in turn traps more radiation, and the cycle continues, warming the planet.

There is a distinct correlation between increases in greenhouse gases and temperature increases due to this relationship. Scientists know that temperatures are rising through looking at ice core records and measure radiative forcing using specific instruments. Click here to learn more about how scientists measure climate change.

Concentrations of CO2 in 2012 – at 392 parts per million from the Mauna Loa Observatory in Hawaii.

The EPA (Environmental Protection Agency) of the USA say that increasing greenhouse gas emissions will produce many changes to our environments and will:

These changes will impact our food supply, water resources, infrastructure, ecosystems, and even our own health.

See (Climate Change – what’s in store)

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