Final Week of the “Climate Change” Course

Welcome to the Anthropocene

In 2000, scientists Paul Crutzen and Eugene Stoermer invented the word “Anthropocene” to denote the ever increasing influence of humans on Earth. It has since become a word popularly used in scientific literature to express the degree of environmental change on planet Earth, caused by humans. Never in the Earth’s history have humans caused as much environmental change as they do today. This information comes from The British Geological Society, where you can read about it in much more depth.

Landscape Impact

The impact on the landscape first started when prehistoric people started to dig through the earth for stone to make implements. Since then humans have modified the landscape through the excavation of rock and soil, the generation of waste and the creation of artificial ground. An estimated 57000 million tonnes of earth and rock is now shifted annually by humans, compared to just 22000 million tonnes of sediment annually transported by our rivers and oceans. As the population increases, so does the amount of earth and rock that is moved by humans. We directly move material in the following ways:

  • burial and defensive purposes
  • construction and infrastructure for settlement
  • industry
  • mining
  • processing of metal ore
  • waste generation

We also indirectly cause material to be moved. Humans expose soil through agricultural activities, and sediment is deposited as a result of dam construction. This material is then transferred through wind and water.

Atmospheric Alterations

It is not just the landscape that has changed through the actions of humans. Since the beginning of the Industrial Revolution, levels of carbon dioxide (CO2) and methane (CH4) in the atmosphere have soared.

Sea Level Rise

The next threat to humans is one of sea level rise. We are already seeing how our UK coasts are being battered by high winds and rising tides. This is only set to get worse as the Earth’s temperature rises and more and more Arctic ice melts and falls into the sea. According to the Intergovernmental Panel on Climate Change (IPCC), sea levels have risen some 3.1 mm per year since 1993. Around the world, we are seeing the effects of this already. Low-lying island nations, especially in equatorial regions, have been hit hardest and some are threatened with total disappearance. On Samoa, thousands of residents have moved to higher ground as shorelines have retreated by as much as 160 feet. Could we see this happening in other countries around the world, especially smaller islands, such as the UK? What would this cause? Could we see wars breaking out over the ownership of land?

What we do now will affect the future climate for years to come. So, as part of this week’s course, we asked what we, as individuals, can do to help our planet recover? After doing a little research and discussing the issue with other course members, I have come up with these suggestions:

  • Insulate your walls and loft
  • Turn off any lights or electric appliances that aren’t being used
  • Walk, cycle or use public transport where possible
  • Work online from home
  • Install double glazing
  • Lower the central heating thermostat
  • Recycle as much as possible
  • Try growing your own fruit and vegetables
  • Eat less meat
  • Switch off electronics at the wall
  • Buy energy efficient appliances
  • Reduce food waste

Your Carbon Footprint

A carbon footprint is described as the amount of carbon dioxide that enters the atmosphere because of the electricity and fuel you use. It mostly depends on:

  • how much energy you use to heat your home
  • the electronics and appliances you use
  • what kinds of transport you use day-to-day
  • how often you fly

You can calculate your carbon footprint at the DirectGov website. Mine came out as follows:

  • Home – 1.32 tonnes per year
  • Appliances – 1.29 tonnes per year
  • Travel – 0

Overall that is a carbon footprint of 2.6 tonnes a year. It was interesting to compare my total with others on the course and on the website. The national average is 4.46 tonnes a year. I found that my travel was low because I don’t own a car anymore and I rarely go out. When I do, I rely on lifts from other people. I am sure my score is more than 0, but it is a difficult one to calculate in my case. My appliance use was higher than the NA of 0.76 tonnes per year. I think this reflects my lifestyle. As I am ill a lot of the time and don’t go out much, I spend a lot of time at home watching television or using the computer. However, it is one a need to watch and could maybe lower if I remember to turn things off instead of leaving them on standby, or maybe unplug devices that I am not using.

It is an interesting thing to think about and as the UK aims to reduce carbon emissions by 80% below 1990 levels by 2050, we can all do our little bit to help. Many towns and cities around the world are joining the Transition Network. Our town, Honiton, has joined and we have made a start in making our town “greener”. There is now a herb wall in town, tended by volunteers and available to anyone who would like to stop by and try some of the home grown herbs. We have a gardening group that tends any patch of land they can find in the town, planting seeds and keeping our green areas looking good. They have also planted trees in some of our parks. They promote Fairtrade goods by having a regular fayre in the town’s Mackarness Hall where they also host many other fundraising events, and lots more. Check the Transition Network website to see if your town is linked and then see if there is anyway you can get involved.

That is the end of this course. I believe it will be run again later on in the year if anyone wants to join. It is well worth doing and you learn a lot about climate change and how it is affecting the Earth. I had never heard of snowball earth before I joined this course and it didn’t occur to me that carbon dioxide could so badly effect sea creatures. It has really opened my eyes and made me much more thoughtful about how I use electricity, for example. It has also posed many questions that I will continue to research. I would like to learn a lot more about the different forms of sustainable energy and what, if any, are being proposed locally. I am already looking at other courses on Future Learn and I intend to sign up for another one straight away!

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Solutions to Climate Change

Mitigation and Adaptation                           Olympic_rainbow_and_lake-3022012-6-2458 (300x169)

So, we have established that our climate is changing. To a certain extent there is little we can now do about it. It is too late to repair the damage already done, so we must learn to adapt and live in a world where we will see heat waves in some countries, while others are suffering snow storms or hurricanes. So, how do we adapt our lifestyles so that we can survive on a different, perhaps more unstable planet earth?

The other question we are now asking ourselves is how can we be kinder to our planet and stop damaging it further? The scientists describe this as “mitigation”. We need to change what we are doing and stop stripping the Earth of its natural resources. We also need to stop filling the atmosphere with carbon dioxide and other greenhouse gasses so that our planet doesn’t become completely uninhabitable to future generations. That means we need to find other forms of power to generate the electricity that we have all become so reliant on. We also need to find other ways of keeping warm in our cooling winters and staying cool in our warming summers.

Reducing Carbon Emissons

We can do this in two ways. Firstly, we can try and use less energy. Simple things like turning off lights when we leave a room, not leaving televisions and computers on standby, lowering the thermostat in our homes and instead wearing more clothes in the winter, insulating the walls and lofts in our homes so that less heat escapes. We could walk or try riding a bicycle instead of taking the car everywhere.

The other way we can reduce our carbon emissions is to find other sources of energy. If we can find renewable sources, such as water, solar or wind power, we can guarantee that our future generations can live as well, if not better, than we do today.

Adapting the Built Environment

The Technology Strategy Board released a comprehensive report called, “Design for Future Climate”. You can read the full report at their website, which is www.innovateuk.org.

The report is split into three main categories:

  • Designing for Comfort
  • Construction
  • Managing Water

Designing for Comfort

Our summers are going to continually get hotter. At the moment there is no statutory maximum internal temperature in the UK building regulations or health and safety guidance. Current norms are around 24 degrees Celcius, plus or minus 2 degrees. It is believed that above 26 degrees Celcius, people begin to feel uncomfortably warm and there are current studies looking at the effects of too much heat in buildings and what it does to people. Many of our current buildings overheat in the summer and this will only get worse if nothing is done.

There are four strategies identified for dealing with temperatures in our buildings:

  1. High levels of internal thermal mass to make use of lower night-time temperatures
  2. Very careful exclusion of solar gain
  3. Airtight construction and controlled secure ventilation
  4. High levels of insulation

We may need to adapt our lifestyles and look towards Europe for inspiration. Maybe we will start work earlier in the mornings and take longer lunch breaks? As temperatures rise this will have to be looked at.

Active cooling, such as air conditioning will become a necessity, but at the moment it is very carbon intensive. We need to develop carbon-efficient cooling techniques. Buildings that are not suitable for adaptation will become unusable and have to be replaced.

There are great opportunities for innovation as we will need to develop things like shading systems, glazing and film technologies to improve sun exclusion in windows, reflective solid materials, night-time ventilation systems and cooling control systems that use less energy.

Outside, shade will become essential. We will need to look at different plants and trees that need less water than some of our current species. Green and blue spaces that reduce the urban heat island effect will have to become part of our cities and towns. We will need more trees, plants, gardens and parks, as well as rivers, canals and lakes.

What about keeping warm in our colder winters?122111-208 (300x169)

We will need very effective insulation, and new heating systems will need to be developed that use solar, tidal or wind power.

2. Construction

Building design should be robust enough to withstand the anticipated extremes in weather that we will experience. For example:

  • Drier summers could crack and shrink clay foundations.
  • Trees may wilt in the hotter climate. This could affect the foundations of buildings built nearby.
  • Dry land could lead to subsidence.
  • Peat soils could be permanently damaged by drought
  • Older, rigid underground pipework may crack in dry soil.
  • Slopes and retaining structures such as embankments, drainage systems, flood defence berms and landscaped mounds may become unstable in particularly dry or wet weather conditions, especially in the dry, wet, dry, wet patterns we are seeing.
  • It is unclear how our current buildings will withstand stronger winds as there is not enough data to model predictions. We can only go by historical records at the moment. It is believed that older buildings are more at risk from strong winds.

3. Managing Water

  • The construction industry plans to use 20% less water.
  • Drinking water will be in increasingly short supply, so this will have to be addressed.
  • Most houses will be metred as it is proven that they use less water.
  • Grey water systems will become the norm.
  • Blue amenity space will become more important.

Drainage

Some issues when it comes to future drainage are identified in the report and will hopefully be addressed:

  • Larger capacity building gutters, downpipes and drainage may be needed to deal with projected increases in extreme rainfall.
  • Opportunities to store water at high levels should be explored as it helps gravity, rather than using pumps for underground water tanks.
  • As we use less water to flush toilets, foul sewers may fail to function properly.
  • Drains may be overwhelmed by extreme rainfall. This combined with the fact that grassy areas are being concreted to create parking in front gardens could cause problems.

Flooding

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The increase in rainfall and flash flooding could cause problems, so the Technology Strategy Board have identified these issues:

  • Sustainable urban drainage systems (SUDS) design parameters may need reviewing.
  • Design teams need to consider urban flash flooding.
  • Ground water levels may change.
  • Flood defences may increase ground water level.

Eco-friendly Housing

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To be an eco-friendly or “sustainable” house, it must ideally do two things:

  1. Be built with kindness to the environment in mind. For example, use recycled or sustainable, locally sourced materials and insulate to trap heat in the winter, and ventilate to let heat escape in the summer.
  2. Use sustainable resources to generate energy for heating, cooking etc.

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There are many examples of eco-friendly houses on the internet. On the course we were encouraged to look at local buildings that are making use of sustainable resources. I have found it difficult to find any in Honiton so far, but I will keep it in mind next time I am out and about in the town.

Cropthorne House (300x208)

During my internet search I found a house in Worcestershire that was self-built and very eco-friendly. “Cropthorne Autonomous House” is completely ‘water neutral’ and ‘carbon negative’. All the materials were sourced locally whenever possible and it contains a whole host of innovative, eco-friendly features.

Not In My Back Yard

There has been a lot of coverage on the news about groups that have come together to protest about wind farms, “fracking” and nuclear energy plants in their local area. Everyone wants renewable power sources, but it seems that they don’t want to have to see it or hear it. These people are sometimes referred to as NIMBYs (Not In My Back Yard). However, we are going to need new resources and they have to come from somewhere. Some of these power companies have offered money to local communities to encourage them to be more accepting. They call these ” Community Benefits Packages”. A lot of people have just seen these as bribes and it makes them more angry and resistant.

People need information right from the start. Nothing should be hidden as there needs to be trust on both sides if these energy companies are going to be able to go ahead.

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For example, what do we really know about nuclear energy? Would there be any danger to our residents, especially the elderly and young children?

These websites tell you more about Nuclear Energy:

The Pros and Cons of Nuclear Energy

The Guardian Article

World Nuclear

What about fracking? All over the world, people have reported problems with things like water supplies after fracking, or, “Hydraulic Fracturing”, has taken place nearby. Some have noticed that dangerous gasses have escaped from the earth, and tremors have been felt near to fracking sites. Some people have become very ill and blamed fracking for it. No wonder we are all scared!

These sites give you more information on Hydraulic Fracturing:

BBC News

What is Fracking?

Popular Mechanics

Wind farms may seem harmless enough, but a lot of people have complained that they are noisy. Some say the wind farms have caused illnesses, such as chronic headaches. Other people just don’t want to see them ruin the local landscape that they have grown up with.

These sites tell you more about Wind Farms:

The Guardian Article

Energy.Gov

Clean Energy Ideas

What about Off Shore Wind Farms? This article tells you about a group called Slay the Array, who managed to stop plans for an off-shore wind farm off the coast of eats Devon:

BBC: Atlantic Array Wind Farm Rejected

So, would off-shore wind farms be appropriate anywhere as a source of energy, or would the harm to local wildlife always be too much of an issue? What are the advantages and disadvantages of off-shore wind farming? The following sites give you more information:

Renewable Energy Articles

Energy and Technology Magazine

Renewable UK

Reflections on Week 7

The most important themes I have learned this week are mitigation and adaptation, and the challenges and some solutions to the issues of climate change.

I found the amount of content a little overwhelming this week. It is not easy to address all the solutions to World climate change in just one week. It definitely got me thinking, though. I found it difficult to find examples of eco-friendly buildings in my area. Perhaps that is because it is such an old town. I am sure there must be some, I just need to get out and look, although, not easy when you find walking hard!

I found looking at the new eco-friendly houses really interesting. I love all the new innovations and I am amazed at how you can make a kitchen worktop from old vending machine plastic cups as they did in Cropthorne House!

I did a lot of research on eco friendly housing and ended up looking at small communities of people that have started living completely self-sufficiently, like these people in Wales http://www.youtube.com/watch?v=U3FAlByYnoE

A really interesting week. I can’t believe that next week is our last! Still, the course has taught me a lot and it touched on many things that I would like to investigate further.

Urban Heat Islands and Global Food Security

 

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Urban Heat Islands

City Skyline

City Skyline

In week six of the course, we have been learning about so called “urban heat islands”. Two hundred years ago, a scientist called Luke Howard measured the difference in temperature between the city of London and the surrounding rural areas. He noted a difference of 2 degrees Celcius. Studies in and around London in the 1960s noted a difference of around 4 degrees Celcius.  In 2003, that figure reached 9 degrees Celcius, although this year in particular saw above average temperatures.

Why are cities so much hotter than the countryside?

  • Buildings absorb and reflect heat
  • They block wind, inhibiting cooling by convection
  • Sewers carry away water, preventing cooling by evaporation
  • Waste heat from buildings and cars also increases the temperature

The dangers of these urban heat islands were seen in the 2003 heat wave. It is estimated that up to 70,000 people died across Europe as a result of dehydration, hyperthermia and heat stroke. Most deaths occurred in cities and especially on the upper floors of buildings where the temperatures were at their highest.  Also, most of the deaths occurred at night because people tend to close doors and windows for security purposes and they cover up to go to sleep. Although, even if they had left their windows open, it wouldn’t have helped much as there would have been very little convection due to the still air surrounding the buildings.

Air conditioning is a great way to keep cool in a hot, city building, but sadly it also increases the heat outside and adds to the emission of CO2. Other ways of cooling cities are being looked at across the World. In New York there is a scheme that encourages people to paint their roofs in a light colour so as to increase the albedo effect of the city and reflect some of the heat back into space. Other ideas are the green roof schemes that look at using flat roofs to grow grass and rooftop gardens.

Other ideas are to paint all dark surfaces in lighter colours, for example roads, pathways and car parks could be painted or a lighter colour surface could be used when designing a new city.

Lighter coloured cars also reflect heat, unlike darker cars that soak it up. If people were taught about urban heat islands and the albedo effect, they could be encouraged to buy a lighter colour car. It is more comfortable for the driver and passengers, too, as it stays cooler in the car park than a dark car would.

These websites tell you more about urban heat islands and what cities around the world are doing about them:

Sustainable Cities Net

NASA

NYC Cool Roofs

London Urban Heat Island

Wikipedia

Global Food Security

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Our population today is around seven billion. It is estimated that by 2050, it will reach 9.2 billion. 86% will live in less economically developed countries. The question is what will these nine billion people eat? To feed them all, our food supply needs to double over the next fifty years. However, with climate change, a lack of a good water supply, and disease all threatening our crops, that is going to be a hard task.

40% of agricultural land produces just three main crops. These are rice, wheat and maize. Rice provides the main calorie intake for half the world’s population.

Since the 1960’s, we have had a massive increase in global food production thanks to fertilisers, herbicides, pesticides and fungicides, as well as greater farm mechanisation and intensification. This has lead to a trend of growing large amounts of one particular crop. This means that if a disease were to hit that particular variety of crop, a lot of our food would be wasted. Over the course of history we have seen pests and pathogens destroy miles of our crops and lead to human poverty and hunger.

Currently, fungi challenge our three main crops and cost the global economy $60 billion US every year. As our climate changes, new diseases are being found in new locations. For example, these fungi and pathogens are moving over 7 kilometres per year Northwards from the equator. They are challenging crops that have never seen them before. Scientists are working hard to find ways to protect these crops from attack by the travelling pathogens. They are facing this challenge in three ways:

  • Boosting the immunity of plants
  • Using bio protection
  • Developing antifungal chemistries

We need to raise the awareness of the public and our politicians to the plight of our plants with respect to crop disease. The following link will take you to the Global Food Security Programme website where you can find out more about how climate change and other factors are affecting our food security in the future.

Global Food Security Programme

Reflections on Week 6

The most important themes I have learned this week are the challenges of urban heat islands and of global food security.

I found all the facts and figures relating to global food security very difficult to get my head around. The Global Food Security Programme site had so much information on it, I wasn’t sure where to focus my attention. I feel that this subject could do with its own course! There is so much involved, I found it quite overwhelming.

I found the first part of this week the most interesting. I enjoyed learning about urban heat islands as I had never heard of them. I am impressed that so many countries around the world are starting to do something positive to cool their cities down. I loved the New York City Cool Roofs project very inspiring and I hope this idea spreads across other parts of the world. I enjoyed dreaming up my own environmentally friendly, cooler city, too.

Both topics prompted me to do my own research. I found many different websites on urban heat islands and I have listed some of them further up the page under the section of that name. I found a lot of you tube videos on global food security and the growing population. I thought videos might help me understand better, rather than looking at pages of facts, figures and endless percentages!

I found these videos and websites most interesting and got caught up in Dr Evan Fraser’s work “Feeding Nine Billion”. He has a website and a series of You Tube videos. You can find them by following these links:

Feeding Nine Billion

Feeding Nine Billion Video

This film about the increasing global population was a bit off topic, but was interesting, nevertheless!

Hans Rosling: Don’t Panic!

Climate Change – Future Learn – Week 5 Reflections

This week we learnt about the Cryosphere, which is the ice and snow, and looked at how the glaciers in Antarctica and Greenland are melting.

We also looked at Ocean Acidification and learnt about how CO2 is changing the pH levels in our seas and oceans.

 

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            The Cryosphere – Main Points

Antarctica and Greenland’s glaciers make up 99% of the glacier ice on Earth. If it were all to melt, it would cause the sea level to rise by 65 metres.

An “ice sheet” is a mass of glacier ice that covers surrounding terrain and is greater than 50,000 square kilometres. The only current ice sheets are in the Antarctic and Greenland.

Masses of ice covering less than 50,000 square kilometres are termed an “ice cap”.

Prior to 2000, it was believed that the precipitation in the middle of the glaciers would make up for the amount of ice melt around the edge. This has not been the case. The small amount of precipitation cannot keep up with the rate that ice is melting into the sea, causing a negative mass balance.

Huge blocks of ice at the edge of the glacier are breaking up and falling into the sea, forming icebergs. This is called calving. It is a natural process, but it is happening far too rapidly.

2012 saw above average melt extent across the whole of  the Greenland ice sheet. It was the largest in the satellite era, extending up to 97% of the ice sheet surface and lasting two months longer than the 1979 to 2011 mean.

Lakes are created by melting snow and ice. The sun heats these lakes and causes them to flow down to the bed, where the meltwater has a lubricating effect on the ice sheet flow, causing it to move more quickly into the sea.

High spots on the sea bed, or ice shelves are used as buttresses to stop the snow and ice sliding into the water. If the ice shelf melts, there is nothing to stop more of the ice sheet from falling into the water. This happened at Jakobshavns Isbrae, Greenland, one of the fastest flowing glaciers in the world. Since measurements were first taken in 1850, the glacier has gradually retreated and added to the sea level.

“Jakobshavn Isbrae alone has contributed nearly 1mm to global sea level over the period from 2000 to 2011”   (Howat et al., 2011)

Scientists have noticed that the melting and calving of the glacier has sped up in summer but not replenished itself in the winter:

“Since the loss of this ice tongue, the glacier’s speed has varied, seasonally slowing down with the terminus advance in winter and speeding up with terminus retreat in summer.”  (Joughin et al., 2012)

These websites have some interesting further reading:

Polar Portal

Antarctic Glaciers

Glacier Works

Helheim Glacier : Time lapse of calving event

National Snow and Ice Data Centre

Ocean Acidification – Main Points

Ocean’s cover 70% of the Earth’s surface.

Ocean’s contain 99% of the living space for animals on Earth.

There’s about 250,000 species living in the ocean, that we know about. There are plenty that we haven’t yet discovered because of the depth of the oceans and the difficulty in exploring them.

One in every three breaths that we take comes from oxygen produced by phytoplankton living in the oceans.

Marine invertebrates make up 76% of the species in our oceans.

About a third of all atmospheric carbon dioxide is absorbed by the ocean and it is causing a series of chemical reactions, leading to ocean acidification. Carbon dioxide combines with the sea water to create carbonic acid. The carbonic acid dissolves into bicarbonate and hydrogen ions. The concentration of hydrogen ions in seawater determines its pH level. At the moment it is about 8.1. So, as carbon dioxide levels increase, the hydrogen ions increase and the pH level falls.

Ocean Acidification (300x205)

Since the Industrial Revolution, the pH level has fallen by about 0.1 of a unit. That is a 30% increase in hydrogen ions, which is a shock to the marine animals.

If we carry on as we are, there will be a 120% increase in hydrogen ions by the end of this century. That is about 0.3 to 0.4 of a pH change. It is changing faster than any other time in the last 300 million years.

The pH level of the ocean has remained stable for millions of years because carbonate ions have  acted as a natural buffer by soaking up hydrogen ions and keeping the pH level stable. However, they are no longer able to keep up with the rate of hydrogen ions in the water.

Shells are made out of calcium carbonate, as are skeletons. As ocean acidification continues, there will be less carbonate ions in the ocean to form shells and skeletons. Those already formed will start to dissolve.

In the cold polar waters, where there is more carbon dioxide dissolving in the water, there is evidence of dissolving shells already.

Many marine invertebrates reproduce by releasing their eggs and sperm straight into the ocean. As they are so small, they will be directly affected by the seawater conditions. It is likely that many marine invertebrates will fail to reproduce successfully under these new conditions.

Scientists are researching ocean acidification in research aquariums, like the one in Exeter. They are looking at the impact of ocean acidification (OA) on commercially important shellfish species, such as native oysters.

Scientists bubble air that is at the level expected in 100 years time, into the seawater, to mimic OA conditions. They study the animals to see how they will react.

Other factors, such as environmental pollution and chemical contamination are also affecting marine life.

Coral reefs are dissolving as the water becomes more acidic.

Many people around the world depend on fish for food and livelihood. As the smaller creatures disappear, the larger fish will have no food and so they will also begin to die out.

These websites provide interesting further reading:

Climate and Capitalism

NRDC- National Resources Defense Council

NASA

Reflections on this week:

I enjoyed this part of the course, especially learning about marine life. I would like to learn more about how climate change is affecting sea life. I would also like to learn about how it is impacting on land dwelling animals, too.

Future Projections

Making Future Projections

This week on Future Learn: Climate Change, we have been looking at how scientists use climate models to predict the future of the Earth’s climate. They use extremely powerful computers that do two million calculations every twenty minutes. Nature is much easier to predict than human influences. For example, they can simulate how the temperature, humidity, and wind in the atmosphere will change. They can also predict the temperature and the salinity of oceans and how their currents vary through time. However, scientists cannot know how human influence will affect the climate. They can’t predict how much more carbon the sea and the vegetation will be able to absorb if we don’t do something about the amount of carbon dioxide we pump into the air every day. At the moment they soak up half of the carbon dioxide that floats around in the atmosphere. However, they may reach a saturation point, which means that all that extra carbon dioxide will end up back in the atmosphere, thickening the blanket of greenhouse gases and increasing the Earth’s temperature.

To check that the climate change models are accurate enough, scientists used the computers to calculate the past 150 years and see how true the predictions were. They found that the predictions and the actual climate were very close up until 1970 when the climate was predicted to cool, but instead warmed up. Scientists have to produce different models to predict the next hundred years, depending on the human input. It has been calculated that 90% of global warming has been caused by humans. If we continue in this way, the temperature of the earth could rise another 6 degrees Celsius over the next one hundred years. This would be very dangerous and mean that we could reach tipping point, where the warming will get out of control completely and sea levels could rise by ten metres or more due to the collapse of the Greenland and West Antarctic ice sheets. If we change our ways, the earth may only warm by one or two degrees. So, the scientists make predictions on a number of different scenarios.

These websites describe climate projection much better than I am able to with my basic knowledge! They are all an interesting read, although it is the numbers and formulas that I find difficult to get my head round!

The Carbon Brief

Hadley Centre

BBC; Climate Change

Skeptical Science

This documentary shows what could happen to the Earth depending on how much it warms up over the next hundred years It is called Six Degrees Could Change the World and I recommend everyone watch it.

The Geo-engineering Dilemma

If we don’t reduce our carbon dioxide levels by changing the way we live. For example, recycling, using cars less, cutting back on deforestation etc., then the scientists could resort to geo-engineering, sometimes called climate engineering. This means they would use technology to control the climate. There are two ways to do this:

1. Carbon dioxide removal mechanisms

  • Lock carbon away from the atmosphere in the form of calcium carbonate.
  • Use physical and chemical processes to capture carbon dioxide from the atmosphere.
  • Use biofuel
  • Biochar – heat biomass in a low oxygen environment and create charcoal which captures and locks up the carbon for much longer than normal biological plants.

However, there is a problem with bio-energy. To generate enough biomass for burning in power stations would take a huge amount of land for growing trees. This is in direct conflict with food production. Also, removing the carbon dioxide from the atmosphere would only reduce global warming, it wouldn’t reverse it.

2. Solar radiation management

Brighten the surface of the planet so that it reflects more solar radiation.

  • Use aircraft or giant stratospheric balloons attached to pipes to disperse a few megatons of sulphur dioxide into the high atmosphere, where it would form tiny reflective droplets of sulphuric acid
  • Use ships that already leave tracks of bright cloud behind them. Ship tracks are formed by the emissions of millions of tiny aerosol particles. Cloud droplets condense on these, forming smaller droplets.
  • Clouds with more small particles are brighter and more reflective to sunlight. Sea salt or other aerosol particles could be injected into susceptible clouds, brightening them up.

Although geo-engineering is technically feasible, it could be quite dangerous. If we ever stopped doing it for some reason, the climate would rise in temperature so quickly that many ecosystems would not be able to adapt in time and, therefore, would die out. There are also many other problems with geo-engineering as we don’t know what other effects it might have on the Earth.

I enjoyed learning about geo-engineering, but I have to say, I find it quite frightening and wouldn’t want to resort to messing around with the climate. We could do more harm than good. Surely it is better to change our ways now and try and reduce the amount of CO2 and other gases in the atmosphere? Some people think that by mentioning geo-engineering, people will see it as an easy option and so not bother changing things now. However, I think that people should know about it because I think others would also find it a bit scary and so do something positive now, so that it doesn’t come to that.

These are some websites that explain and debate geo-engineering:

BBC: Geo-engineering

Climate Central

The Guardian: Why has geo-engineering been legitimised?

The Guardian: Why we’d be mad to rule out geo-engineering

How Has Our Climate Changed?

There are 11 key indicators of a warming climate:

  • Global surface temperature has risen 1.6 degrees over roughly the past century.
  • Glaciers have been shrinking and losing mass worldwide. The melt of ice sheets has also accelerated.
  • Water vapour has increased by 4% since the 1970s. As we continue to warm, this will increase the contrast between dry and wet regions. Most regions will be vulnerable to increases in heavy precipitation events.
  • Snow cover is decreasing.
  • Global average sea level has risen 7.5 inches over the past century, with the rate of rise accelerating over the last two decades.
  • The oceans are absorbing a large amount of the additional CO2. Carbon dioxide interacts with ocean water to form carbonic acid, lowering the ocean’s pH. This reduces the ability of marine organisms with shells or skeletons made of calcium carbonate to survive, grow and reproduce.
  • The extent of Arctic sea ice is decreasing. Sea ice is important because it reflects the sun’s radiation and helps cool the planet.
  • The ocean’s ability to store and release heat gives it an important role in stabilising the climate. Upper ocean heat content has increased significantly over the past two decades. While the atmosphere has been spared the full extent of warming for now, heat already stored in the ocean will eventually be released, resulting in additional warming in the future.
  • Permafrost is soil that is at or below freezing for two or more years. Observations indicate that permafrost is shrinking due to increased temperatures. As the Arctic warms, methane and carbon dioxide trapped in permafrost is being released into the atmosphere, increasing its concentration of greenhouse gases. Permafrost thaw in coastal areas increases the vulnerability of coastlines to erosion, infrastructure damage and ecosystem changes.
  • From 1901 to 2012, sea surface temperatures rose at an average rate of 0.13 degrees per decade. Water expands as it warms, contributing to sea level rise.
  • Seasons are shifting meaning a broad impact across the entire ecosystem. Flower buds are emerging earlier when frost is still a high risk, translating into fewer wildflowers and butterflies. It is also affecting migration patterns and causing snow to begin melting earlier.

 

This information was all taken from Climate Central.

Week Two Questions

  • What are climate change records?

Climate change records are used to monitor the temperature of the Earth. The records date back to the seventeenth century and, over that time, scientists have used a number of different ways to collect the data. These include taking sea surface temperatures, using buoys just below the sea, tree-rings, ice cores, temperatures down oil well bore holes and, most recently, weather balloons and satellites. Today, when instruments are updated, there is a period of overlap. For example, when new satellites are sent up, the old one will continue to monitor weather for a while. This makes the process more expensive but also more reliable.

Some of the earlier data may not have been completely accurate, so scientists have developed complex statistical theories to estimate the uncertainties in weather data and global averages.

  • How do volcanoes affect climate change?

Volcanic eruptions can alter the climate of the Earth in two ways. When a volcano erupts, it emits gases and dust particles into the atmosphere. This includes ash and sulphur dioxide which sits above the Earth and reflects the sun’s radiation back out into space. This reduces the temperature of the Earth and this affect can last for a number of years.

In the long term, volcanoes can warm the Earth’s climate. Along with the ash and sulphur dioxide, volcanoes release carbon dioxide into the atmosphere. This sits above the Earth and absorbs heat radiation, holding it in the atmosphere and eventually increasing the Earth’s climate.

  • How is today’s warming different from the past?

We know from climate change records that the Earth has experienced natural climate change in the past. Scientists have used ice layers from glaciers to give them a history of greenhouse gases that stretches back more than 800,000 years. The chemical make-up of the ice provides clues to the average global temperature. Using ancient evidence, scientists have built a record of Earth’s past climates, or paleoclimates. However, the climate is warming far more rapidly than it has ever done in the past.

Models predict that the Earth will warm between two and six degrees Celsius in the next century. In the past two million years it has taken the planet, on average, about 5,000 years to warm 5 degrees during periods of global warming. The predicted rate of warming for the next century is at least twenty times faster than that. This is very unusual.

  • How have trees been used to reconstruct different climate variables across the world?

Every year a tree uses sugars produced by photosynthesis to build a new layer of wood around itself. Therefore, when a tree falls you can count the number of rings that make up the trunk to tell its age. The wider the ring, the better the conditions for growth that summer. Usually this would mean lots of sun and rain. To assess the rings on living trees, scientists use an incremental borer to take a core sample without harming the tree too much. They count back through the rings to get some idea of the weather in that year. To make it a fair assessment, scientists take a number of samples from different trees so that they can compare them. For example, things such as termite infestations can also influence the health of a particular tree. By taking a few samples from each area they can isolate the effects of temperature and rainfall alone.