Climate Change: Challenges and Solutions - reflections on week eight

Hey, it's the last week! This week we are... Looking Ahead.

8.1 Welcome to the Anthropocene - video

Another video presented by Prof. Tim Lenton of University of Exeter.

Key points:

• Humanity is on the threshold of a new geological epoch known as the Anthropocene.
• Exeter cathedral was founded in 1050 CE, when the mean global temperature was about 14 deg. C, and CO2 was 280 ppm in the atmosphere.
• May 2013 saw the 400 ppm level broken.
• If we were to burn all 4,000 billion tonnes of known fossil fuels, CO2 could rise to 1,500 ppm by 2300 CE.
• We could see global temperatures peak at 8 deg. C. higher than pre-industiral mean, and still be 6 deg. C. warmer by 3000 CE.
• CO2 is a more long-lived pollutant than radioactive pollutants, and it would take a million years for all the CO2 from fossil fuel burning to be returned to the lithosphere (solid part of Earth's crust and mantle) by silicate weathering.
• If we burn all the fossil fuels known, then we will break the approx 100,000 year ice-age cycle that has held true for the last 850,000 years, possibly entering a permanent hot period.
• This could see sea-levels rise by 10s of metres, and formation of a distinct new layer of sedimentary rock.
• But that assumes we actually burn all the fossil fuels!

8.2 Defining the Anthropocene - article

An article on the British Geological Survey's website on "The Antropocene".

Good bit to quote: Humans have caused a dramatic increase in erosion of the land surface and changes in sedimentation, through agriculture and construction, and also by other activities such as the damming of most major rivers. As well as these physical changes, the signal of chemical pollutants and radioactive waste that we have accumulated over the past 200 years will leave a signal that stretches into the distant future, and one which would be identified by geologists millions of years hence as identifying the Anthropocene. 

8.3 How might it affect you? - discussion

How might rising sea levels affect you? With a link to this article in New Scientist. Which should have been this one.
I live in Exeter, so wouldn't directly be affected by rising sea-levels, but many of the towns and areas nearby would be. This winter we have already seen extensive flooding on the Somerset Levels nearby, and the rather spectacular damage done to the coastal railway line at Dawlish. The rail link to Bristol has been affected by flooding, and the rail link to London Waterloo was closed briefly due to a landslide. There has been a lot of erosion of the cliff faces in Sidmouth, the sand dunes have almost disappeared at Exmouth, and there has been lots of flooding and damage to walks and parks on the Exe estuary banks in Topsham. All of these have accumulated effects in changes to property values, the ability of the local economy to function through it's connections to the rest of the country, and possible impact on the tourist industry, which is a large employer in the South West of England.

8.4 Action - video

Presented by Prof. Tim Lenton.

Not sure I got a lot from this video, it's mainly wrapping things up and urging us to take action on a personal level to limit our greenhouse gas emissions.

Key points:

• Kyoto Protocol signed in 1997 expires in 2020, commits to keeping climate change to below 2 deg. C. achievable though a 60% reduction in emissions.
•  This is a huge task, and for developing nations to continue developing, means those of us in developed nations need to cut back by even more.
• There is a bit of spiel from Exeter University Sustainability Manager - they have reduced carbon emissions by over 40% since 2005/6 - which is quite an acheivement I think.
• They have done this through technical fixes: draft-proofing, improving lighting controls, and improving the controls on boilers and adoption of renewable energy sources: ground source heat pumps and biomass boilers.
• We can reduce our footprint by flying less, driving less, using public transport and cycling more. Also doing things online and working from home over the internet.
• Can we de-couple economic growth from environmental degradation? Still unclear how to do this.
• Scientifically there is still much uncertainty around how much carbon will be taken up by vegetation, soils and the oceans.

8.5 Your carbon footprint - article

Article on the Energy Saving Trust website.

8.6 Take action: calculate your carbon footprint - discussion

A link to the the online calculator at the DirectGov website.

Using this my household may produce 1.2 tonnes of carbon (presumably this is per year?).
My appliances probably emit 0.49 tonnes of carbon per year.
My travel may emit 1.83 tonnes of carbon per year.
My total carbon footprint is 3.51 tonnes per year.

That sounds rather alarming to me, but the national average for my sort of household is 4.46 tonnes (1.99 home, 0.71 appliances, 1.76 travel) - I'm not convinced by that! I don't fly, or regularly commute by car or rail, our family car does a fairly low milage each year. Think I need to look into this a bit more!

8.7 Is the future of our climate still in out hands? - discussion

This has a link to an article in New Scientist. Think they've got this the wrong way round from the other New Scientist link in section 8.3 (the first obvious mistake in the course material!).

8.8 Test

15 out of 15 get in!

8.9 Final Test (Part 1)

Q10 climate impacts of sea ice melting - didn't work out the answer to this.

22 out of 30 without revision or reference to notes...

8.10 Final Test (Part 2)

24 out of 30 this time.

8.11 Reflect - discussion

Well the recommendation is to go back and review the course material if you get less than 25 out of 30 for the to tests. Some of the questions recollection of obscure facts from several weeks ago, and felt a bit arbitrary! Anyhow, the thing is done and I enjoyed it. I shall write up a proper reflection another time, as it's getting late...

Climate Change: Challenges and Solutions - reflections on week seven

Wow week seven, on the home straight, but I'm also running a week late, so this one might be a bit rushed...

Week 7: Solutions

7.1 Mitigation and Adaption - video

Dr. Tristran Kershaw returns with a brief video, looking at the two key approaches to tackling greenhouse gas emissions - mitigation and adaptation.

Main points:

• Two ways of tackling greenhouse emissions:
• reduce - use less energy, be more efficient, switch off lights, turn down heating etc
• de-carbonise our energy sources - use renewables rather than fossil fuels, UK currently generates 11% from wind, solar and tidal power

1. mitigation - cut back what we do now and attempt to minimise our emissions
2. adaptation - change the way we do things in order to survive what will change anyway

• "locked-in" climate change is inevitable due to greenhouse gases already emitted
• Montgomery Primary School, built in 2011 with PassivHaus energy efficient guidelines, is the first zero-carbon school in the UK
• generates all it's own energy needs
• cleaver ventilation schemes moves hot air from classrooms to cool corridors
• heavy weight structure mitigates against warming, stays cooler during the day, cools at at night through roof vents
• problem is, we won't rebuild all our buildings from scratch, some need to be adapted

7.2 Adapting The Built Environment - article

A rather large document about new building designs.

7.3 Building Design Near You - discussion

We're invited to take a picture of a local building and discuss how has been built with climate change adaption in mind.

The sustainable and environmental components of the constructions are all emphasised for the Exeter and East Devon Growth Point. I found a 3D fly-through of a number of proposed developments happening nearby, including homes, offices and hotels, changes to the local airport, construction of a rail freight point, and a community energy generation plant, and a Science park. So the housing can all be seen to be surrounded by open green spaces, built to high energy efficiency standards, and utilise a purpose-built nearby combined heat and power plant.

7.4 Not In My Back Yard! - video

Prof. Patrick Devine-Wright presents this, there is also a linked article about the Climate Change Act.

Main points:

• interested in social dimension of de-carbonisation of energy supplies
• wholesale changes to energy generation means changes to our land and seascapes etc. - e.g wind turbines and farms
• governments and companies have dealt with "nimby-ism" in a number of ways
1. move away from peoples back yards, i.e. away from where people live and are affected, e.g. off-shore wind generation
2. information - presume that better informed people will be more receptive to having things built near them
3. deal with presumption of selfishness - e.g. community benefits packages - ensure profits to stay locally, often seen as a bribe
• so these responses don't always work
• two important concepts
• "procedural justice" - what people are told when, and how much involvement they have in the decision process affects likelihood of acceptance
• "place attachment" - refers to bonds from people to where they live and how they define themselves
• change needs to be "bottom up" rather than "top down"
• can we develop power supplies within communities?, will the existing big companies prevent this

7.5 Community Benefits Packages - article

On the Renewable UK website, which provides "the voice of wind and marine energy", there is a linked document "Onshore wind: Our Community Commitment", and a statement that "Under the Protocol, developers in England with qualifying projects commit to provide community benefits of £5,000 per MW of installed capacity, or equivalent benefits-in-kind, directly to host communities".

7.6 NIMBYs in Action - discussion

One protest that interested me, as I grew up and lived near Fairmile which became one of the more infamous anti-road building campaigns back in the 1990s. I ended up reading a few pages of this book Direct Action in British Environmentalism on how the protesters were themselves portrayed. In one way they were perceived not as NIMBYs (i.e. by definition concerned local individuals) but as "unemployed outsider activists rejecting the values of 'normal' people". But as the press was largely supportive of the cause, (being against unfettered road-developments, and reflecting that of it's readership), then the personal portraits of the protesters were then constructed to "normalise" them. E.g. Swampy is put in an Armani suit and Animal's GCSE results, membership of MENSA and middle-class background emphasised.

7.7 Test

15 out of 15 again this week!

7.8 Reflections

There was nothing too difficult to understand this week, I've just got behind with stuff. The differences between mitigation and adaptation are something I need to get straight in my mind, mitigation is trying to stop it getting worse, adaptation is accepting climate change is happening and dealing with it.

Climate Change: challenges and solutions - reflections on week six

Week six, goodness me, on the home stretch now, this week we are learning about... Impacts on Human Systems.

6.1 Human health and the built environment - video

Presented by Dr. Tristan Kershaw

Another new topic for me. So keys points of interest were:

• The building industry accounts for over 50% of CO2 emissions in Britain, and is even higher in some other economically-developed countries.
• Three concepts were introduced:

1. Urban Heat Islands
• Concept first noted by Luke Howard 200 years ago - temperature difference between London and the surrounding countryside about 2 deg. C.
• In the 1960's - about 4 deg. C.
• By hot summer of 2003 difference was 9 deg. C.
• Factors that create heat islands:
• The built environment is good and absorbing and reflecting heat back on to surrounding buildings
• buildings block wind - hence less convective cooling
• better drainage - dry environment with no evaporation going on
• extra heat comes from industry, vehicles and air conditioning systems
2. Heat Waves
• a period of hot weather prolonged over several days
• the heatwave of 2003 killed 70,000 people across Europe
• the causes were mainly dehydration and hyperthermia (heat stroke)
• majority of deaths were in buildings, at night, on the upper floors
3. No name given for the third concept - but your body is an engine that produces heat
• you typically burn about 100W just watching a video
• you know how you cool down (behaviours, and sweating etc)
• if you're unable to cool down at night, any heat built up in the body during the day may mean you cook (?)
• rate of heat loss is dependent upon environmental conditions including temperature, humidity and air movement

• So in the 2003 heat wave across Europe, the vast majority of deaths were in high-rise buildings. Opening windows failed to cool people as the heat wave was calm weather with little wind, heat island effect increased the temperature even more as a result.
• If everyone was to install air-conditioning this would mean more CO2 emissions and more heat waves!

6.2 Urban Heat Islands - article

This article on the NASA website, and this article on the NASA Earth Observatory.

The first article is mainly around a study done of north-western American cities, attempting to determine what factors lead to the greatest heat island effect. Points of interest:

• Method: comparison and use of various satellite images including surface type, temperature, and visible images.
• Cities surrounded by forests show the greatest heat island effect - this is due to the contrast between city and surrounding land, cities in deserts may actually be cooler than the surround deserts.
• The distribution of building types in the city also affects the strength of the effect - denser city centres lead to more pronounced heat islands.
• Shocking fact: "The U.S. Environmental Protection Agency estimates that, between 1979 and 2003, heat exposure has caused more than the number of mortalities resulting from hurricanes, lightning, tornadoes, floods, and earthquakes combined".
• Mortality rates are affected most in the elderly and weak.
• Use of air-conditioning may lead to a rise of external temperatures - the heat presumably is pumped out into the surrounding streets.

The second article compares two images of Baltimore - land surface temperature, and land development intensity. The presence of large areas of parkland with cooler temperatures is really noticeable.

Q. How do you think the land use planning in urban heat islands could be used to reduce the scale of such islands?

A. So from these two articles it seems having smaller cities, more even distribution of development, with areas of open planting and naturally draining surfaces would all contribute to reducing the heat island effect. There are also corrective actions that can be taken, such as reducing use of air-conditioning, and painting roofs white to lead to less heat absorption. Lining streets with trees and creating green roofs would also lead to more shade and transpiration where it is needed the most. Also, positioning buildings to funnel air-flow through the city would help keep it cooler.

Interesting fact: Someone on the discussions pointed to this article - a cool car needs a 13% smaller air-conditioner, leading to a 1% improvement in fuel-efficiency overall!

6.3 Climate Change and Food Security - video

Presented by Prof. Sarah Gurr.

Key points for me:

• World population now approx. 7 billion, expected to reach 9.2 billion by 2050.
• 40% of the worlds agricultural land produces just three crops - wheat, rice and maize
• rice accounts for the main source of calories for 50% of the worlds population
• the main threat to these three crops are three particular fungi
• potato blight caused loss of 15% of Irish population during the potato famine
• distribution of harmful pathogens is shifting due to climate change - in a warming world they are moving toward the poles
• research is being carried out in three forms to protect against these effects: i) breeding varieties with stronger resistance, ii) using bioprotection using microbes found in the soil, iii) more "rational" ways to protect crops with antifungal chemistries - I guess this means better anti-fungicides(?)

6.4 The Global Food Security Programme - article

Website with lots of articles, including an FAQ, including, Does climate change affect food security?


6.5 Tackling Food Security - discussion

Q. With a growing population and improving diets there is a need to double our food supply by 2050. Identify three measures you would take meet this demand. Identify one of your measures from your list and post your solution into the discussion - be prepared to defend your choice!

A1. Be more efficient with what we already have - reduce waste either through the way food is distributed through markets and in individuals homes and shops in the developed nations.

A2. Be more effective in production - that means grow the most appropriate crops in the most appropriate ways, e.g. choice of varieties, use of fertilisers, fungicides and herbicides etc. Continue the "green revolution" to produce more food.

A3. Diversify our food sources - make ourselves less dependent upon just three food types - rice, maize and wheat, that may be at odds with the answer above!

6.6 Test

15/15 again this week, woo-hoo!

6.7 Reflect

I think on the whole I found this week slightly less engaging, I'm not sure why. I guess these two topics are more about the impacts of climate change on people, whereas up to now I've been primarily interested in the identification and prediction of climate change in itself. It took less time than some other weeks for me. Interesting topics all the same.

Climate Change: challenges and solutions - reflections on week five

So here we are in week five, over half-way through... this week we are looking at: Impacts on Natural Systems.

5.1 Impacts on land systems - the cryosphere (video)

Presented by Dr. Damien Mansell.

There was a lot of material in this video, on a subject matter I was unfamiliar with, so there was a lot to take in. This is the first video I have had to re-watch, and pause to make notes in, some key points:

• The cryosphere is that part of the Earth's surface that is under ice.
• 99% of the Earth's glacier ice is over Greenland and Antarctica - this has potential (not forecast) to contribute to 65m of sea-level rise (Exeter cathedral in the video is 44m high).
• The last two decades have seen the glacial ice reduce in three ways over Greenland - thinning, less extent (frontal retreat) and increase in glacial flow speeds.
• For Greenland - half of the loss is from surface melt, the other half from blocks breaking off at the edges (calving).
• More snow will cause the glaciers to grow, but if the melt-rate increases to more than the rate added by snow, the net change will be less ice.
• If the glaciers spread more - you will have more ice at the edge - more melting and more "calving".
• On an average summer half of the surface will melt - in 2012 it was 97% and for two months longer than average.
• Surface water at high elevations mostly refreezes in place. At the edges, melt water either flows into the ocean (adding to sea level rise) or stays in place by forming lakes.
• These lakes can be up to 9km^2 in area, are darker and absorb more heat.
• Meltwater reaching the bed of the glacier and acting as a lubricant to make it flow faster is called Basel lubrication.
• So sudden releases of melt water contribute to more rapid spreading of the ice, and transport heat into the ice - which may soften it or cause it to spread more rapidly.
• Floating ice-shelves acts as a "flying buttress" and holds back the edge of the glaciers, slowing down their flow. If the over-sea-ice melts, it doesn't contribute to sea-level rise (it's mass has already been displaced), but it no longer holds back the ice over the land, which then flows out at a faster rate, which does contribute to sea-level rise.
• Something I realised later: sea-ice is ice formed at sea, whereas an ice-shelf is glacial in origin.

5.2 Ice Sheets - article

This is an interesting website showing daily reports on the extent of the Greenland ice-sheets, with reports on where the surface is melting, and the glacier front positions, and a total mass of the ice sheet, showing how it varies through the year, and has seen consistent loss in recent decades. 2012 was an extreme year with the rate of ice loss being outside two standard deviations of the mean.

There is a link to a second article on the marine ice sheet instability hypothesis which is a low probability / high impact scenario where a large part of the Western Antarctic ice could melt and contribute up to 3.3m in sea-level rise. This also links to an easy to read Discovery piece.

5.3 Glacial Retreat - article

Key bit on the GlacierWorks website is this video of the worlds highest photo exhibition, where we are talked through the "then" and "now" photos, where there are modern photos taken to reproduce the views of photos taken by some of the earliest expeditions to the Himalayas. The difference in the extent of the glaciers is truly shocking.

There is also a rather funky tool for comparing one photo with another with a slider to move and reveal one photo against another.

5.4 Calving Events - video

A time-lapse from Swansea Glaciology showing a large calving event at the Helheim Glacier in Greenland in 2010. Apparently this is the biggest calving event caught on camera, and was so large it was picked up by seismologists.

We are also asked to discuss how factors such as air temperature, water temperature, glacier speed and the fjord topography can control calving. Also to identify what are the key controlling processes?

So from what I've learnt above:

Rising air and water temperatures would lead to the melting of sea ice. This acts as a buttress to glaciers, so when this is removed the rate of flow of ice out of the glaciers increases. Warming of the ocean melts ice shelves (part of the glacier over water) from below, making them thinner and more prone to collapse or calving events.

Rising air temperatures also means more surface melting, some of which will flow out, some of which will be trapped in surface lakes. These lakes will also absorb more solar radiation/heat, warming the surrounding ice, making it weaker, and causing it to spread further. If the meltwater reaches the glacier bed it can act as a Basel lubricant increasing the rate of flow of the ice - this leads to more loss through calving as the ice sheet spreads out further. 

The direction of the gradient and whether or not the bed below the glacier is above or below sea-level are also important. Ice melt from above sea-level leads to a rise in sea level. The grounding line is the boundary between the floating ice shelf and the grounded ice feeding it. This line can retreat if warmer ocean water melts the underside of the shelf or there is a major calving event. 

This page ice-shelves is good at explaining ice shelf collapse.

5.5 Ocean Acidification - video

Presented by Dr. Ceri Lewis.

Another fact filled video, on a subject I know next to nothing about, so key points for me are:

• 70% of the planets surface is ocean, this is actually 99% of the living space for animals, as they are so deep.
• 1/3 of our oxygen comes from phytoplankton living in the oceans
• marine inverterbrates make up 76% of the 250,000 known species in the oceans, they are important to us because they are at the bottom of the food chain
• CO2 is really soluble in water, and 1/3 of atmospheric CO2 is absorbed
• CO2 + H20 = H2CO3 (carbonic acid), which dissociates into H+ and HCO3- ions, the concentration of H+ ions means the pH of seawater is about 8.1
• other carbonate ions enter the sea through natural weathering of rocks, or come from the shells of dead marine animals, this creates the "carbonate buffer", which soaks up excess H+ ions keeping the oceans pH stable for millions of years
• we're now adding more CO2 into the atmosphere, and this is getting absorbed by the oceans at a faster rate than the carbonate buffer can cope with, leading to ocean acidification
• pH of ocean has fallen 0.1 (30% increase in H+ ions on logarithmic scale) since the start of the industrial revolution, expected to drop by 0.3 to 0.4 pH units (120% increase in concentration of H+ ions) by the end of the century if we continue to emit CO2 at same rate
• calcium carbonate makes the shells and skeletons of many sea animals, calcification is the precipitation of calcium carbonate into the solid shell form, this is sensitive to dissolution (dissolving) again if the sea becomes under saturated with carbonate ions  
• in colder Arctic and Antarctic waters, where CO2 dissolves more readily we're already seeing under saturation of carbonate ions and some small creatures showing signs of dissolution processes
• larger active animals (such as crabs) produce more CO2 so have better mechanisms for dealing with variations in CO2 levels, but smaller less active animals (such as limpets) can't cope as well and so are more sensitive to CO2 changes
• lots of marine animals reproduce with eggs and sperm released directly into seawater, then form small larvae which in turn develop calcium carbonate skeletons when growing
• this is very sensitive to acidification and exposing sea urchin larvae to acid levels expected at the end of the century show that the larvae don't develop as well, significantly fewer make it to adulthood
• this raises important questions about how can animals adapt sufficiently quickly, and what other stresses will be interacted with in polluted oceans

Links to two more documents

1. FAQs about Ocean Acidification - includes an Ocean acidification chemistry 101 and a neat little PDF 20 Facts about Ocean Acidification.
2. Acid test: the global challenge of ocean acidification - a documentary with Sigourney Weaver (not watched)

5.6 More about ocean acidification - article

• An article on the NASA website, it explains in plain English about ocean acidification, and gives a couple of examples of the impacts.
• It highlights that coral reefs in particular, which are some of the most biologically diverse places on Earth will suffer on account of the reduction in availability of carbonate ions needed to build them, but acidification could contribute to the dissolving of the reefs. 
• Pteropods are small marine snails which support small fishes, and in turn, larger fishes, penguins and whales and seabirds. Ocean acidification strips seawater of carbonate ions needed to build their new shells, and damages their existing ones.
• Ocean acidification will continue even if we stop putting more CO2 into the atmosphere, and the pH could potentially reduce to a level not seen in 20 million years. The rate is happening so fast, it is unclear how marine life and systems will react and how well they can cope with this rapid change.
• NASA has some satellite instrumentation that uses the colour of the ocean to provide information about ocean biology and chemistry.
• There is also a really big question about whether the oceans will become saturated with carbon dioxide and eventually cease to be a sink.

5.7 The impact of ocean acidification - discussion

Two questions to answer:

Q. Will marine organisms be able to adapt to ocean acidification given the time scale for the predicted changes?

A. Well this is an unknown, as the oceans have not been this acidic for maybe 20 million years or more. The discussion groups highlight that major changes to the carbon and sulphur cycles in the past have coincided with mass species extinction events. Ceri Lewis' video explained that creatures higher up the food chain were likely to be more able to cope with these changes, but they are ultimately dependent upon creatures lower down the food chain which are more susceptible. From my limited understanding of natural selection is that evolution can effectively make leaps when situations change, so the question should really be, are there sufficient species able to adapt and maintain sufficient bio-diversity. 

Q. Increased carbon dioxide in the atmosphere is likely to lead to sea level rise. Are rising sea levels more of a threat to humanity than ocean acidification?

This is a tricky one. I think we can see the direct impact of rising sea-levels and quantify these in a reasonably straight-forward way by identifying which parts of the globe will become less habitable and more prone to coastal weather events, and in turn determine the potential social and economic impacts. The impact from ocean acidification acts in two ways, one on the food-chain, of which it is difficult to make an assessment - and what proportion of the worlds population depends upon fish from the sea? The second is how this in turn affects the carbon cycle itself. It "feels like" rising sea-levels are more of a threat, but we don't really know what the full effects of ocean acidification could be, so it's difficult to quantify these. 

5.8 Test

Wow! 15 out of 15 this week, a first!

5.9 Reflect

• Lots of things learnt this week, I knew next to nothing about glaciers or ocean acidification, and now feel I have had a good introduction to both.
• I think this is the first time I've used my A'Level Chemistry knowledge in a long time - all those chemical reactions and equilibriums taking place with ions in the ocean has made me think about things long-dormant.
• I found the glacier video very fact heavy and had to re-watch it - a lot of material appeared to be crammed in to 8 minutes, but the following articles helped to reinforce some of the content. I think a few good diagrams would have conveyed the main points to me in a fairly concise way. That may be my learning style.
• The thing I struggled with the most was the concept of the grounding line and whether or not it's moving to and fro was a bad thing in itself - so maybe more time spent on the Antarctic Glaciers website is in order. I'm not sure that was a key point, but I spent a lot of time mulling it over.

5.10 Feedback video

This weeks feedback video is on YouTube.

Climate Change: challenges and solutions - week four

This week... Future Projections

Section 4.1 Making Future Projections - video

I enjoyed this video of Prof. Peter Cox wandering around the Met Office buildings - where I work!

Key points:

• Similar models are used for forecasting weather and climate - but climate models run over longer time-periods, so different effects (which last over longer time-periods) will play a greater part in modeling the climate rather than predicting the weather.
• These effects include changes to ocean current flows and the change in rates at which the oceans and plants absorb carbon.
• Fingerprinting - is the term for attributing effects to contributions to observations.
• We can have confidence in the validity of the models by seeing how well they coincide with the observation record.
• When forecasting though, this is more difficult because there are still lots of unknown effects that are difficult to model - such as how the carbon sinks effectiveness may change.
• Scenarios are defined to show how human activity may change in the future, such as different rates of population growth and how much CO2 we release - models are then run against these scenarios and the amount of global warming is predicted based on these scenarios.
• I think the use of scenarios is a key point for me, until recently I'd assumed climate models were producing actual forecasts over long time-scales (possibly with different components being includes). When in fact things like the amount of CO2 being put into the atmosphere is not predictable either - it's down to things like the economic cycle, and how we behave as a species going forward. So climate models aren't producing forecasts, they're looking at the effect of different scenarios.

Section 4.2 How much more will the Earth warm - article

A good article on different types of feedbacks and scenarios.

Key points for me:

• I always though more warming would lead to more low level clouds due to more water vapour being present, and this would further contribute to warming as low level cloud would have a blanket effect (compare night-time temperatures when low level cloud isn't present). However this article says low level cloud is close in temperature to the surface temperature, and hence doesn't really effect the overall balance whether they are present or not, due to them re-emitting a similar amount of energy to the surface (similar temperature). But in some parts of the globe, they re-emit energy into abundant water vapour above them, so the energy is absorbed here.
• I always thought high-level clouds contributed to global cooling because they help increase the albedo and reflect radiation back into space. This article says they absorb heat from lower in the atmosphere (that would otherwise escape from the atmosphere), but re-emit less due to their lower temperature, hence contributing to global warming.
• Clouds are confusing and their net effect is difficult to model! I need to think about them a bit more.

Section 4.3 (Optional Step) Run your own climate model - article

• Climate prediction website here
• Alternative Java Climate Model here
• Prof. Peter Cox provided some problems, excel model, and answers.

This all looks really good, but quite time-consuming, and I feel I'm behind schedule again, so I'll move swiftly on to...

Section 4.4 IPCC Fifth Assessment Report - discussion

Read this press release from the 30th January 2014 (topical or what?) from the IPCC Fifth Assessment Report.

Wow, this strikes me as a strongly worded statement about the increasing confidence in the attribution of global warming to human activity and greenhouse gases - phrases such as extremely likely and very high confidence are used at various points.

The discussion point though is "Does the recent change in global temperatures reflect the predictions of climate models?" - the relevent section of the release says that:

"Climate models have improved since the AR4. Models reproduce observed continental-scale surface temperature patterns and trends over many decades, including the more rapid warming since the mid-20th century and the cooling immediately following large volcanic eruptions (very high confidence).

Observational and model studies of temperature change, climate feedbacks and changes in the Earth’s energy budget together provide confidence in the magnitude of global warming in response to past and future forcing."

This article from the Skeptical Science website is rather good for answering the question How reliable are climate models? http://www.skepticalscience.com/climate-models-intermediate.htm

And someone else on the course has done a lot more homework than me http://takvera.blogspot.co.uk/2014/02/exclimate-are-recent-global.html 

Section 4.5 The Geoengineering Dilemma - video

Prof. Jim Heywood introduces us to "Geoengineering".

Main points:

• There are two approaches to mitigating the effect of greenhouse gas emissions - CO2 removal mechanisms and solar radiation management. One seeks to remove CO2 from the atmosphere, the other to reflect more of the suns energy back out to space.
• With CO2 removal mechanisms you need to ensure you expend significantly less CO2 in the activity than you remove in order to make an impact. The best bet seems to be biofuel burning with carbon capture. I was interested to learn that half the turbines at the DRAX power station have been converted to burn bio-fuel. Bio-fuel creation also competes with food production on the same land.
• Solar radiation management introduces small particles into clouds to make them brighter and more reflective. This already happens on a small scale due to pollution from ships creating "ship tracks" above the ocean.
• Any approach taken to geoengineer the climate introduces risk - one, doing it in one hemisphere or the other may cause the tropical rain bands to move - creating droughts in some areas. Failure, or an inability to sustain the geoengineering methods may lead to a sudden jump in global temperature which would be harder to adapt to. The social consequences of these actions would be hard to predict.
• Any geoengineering done would only reduce the impact of global warming unless it could extract more CO2 from the atmosphere than all our activities across the planet add to it.

There are also links provided to two more articles:

• Why we'd be mad to rule out climate engineering
• Why has geoengineering been legitimised by the IPCC?

Section 4.6 Are ideas to cool the planet realistic? - article

Nice little article, I like the quadrant chart showing potential effectiveness versus costs of different solutions.

Section 4.7 Should we geoengineer our climate? - discussion

A link to another article on the BBC website: Geoengineering: Risks and benefits

Q. What is your view on geoengineering? Should it be used to prevent our planet warming?

A. Having read the articles above, my initial reaction is that these methods are in the realms of fanciful science fiction and wouldn't actually solve the problem anyway. I think limited local carbon capture might work as part of an overall carbon emission reduction strategy but there is no "geoengineering silver bullet". There seems to be an interesting debate around the ethics of research into geoengineering - some people find the idea of deployment morally repugnant, and conclude that therefore research shouldn't take place. This strikes me as a rather dogmatic approach, and no area of potentially useful knowledge should, in my opinion, be considered "off limits". However, there is the valid point that the existence of research into geoengineering distracts the eye from the main issue, which is the rising rate of CO2 emission, and we should be focussing our main efforts on collectively reducing these emissions. I think the research should take place, but in a limited way appropriate to the anticipated benefits. I'm wary of widespread deployment of these techniques, as it seems that they introduce lots of risk and the consequences of which may not be entirely predictable - the idea that engineering our climate would have some direct "winners and losers" makes it a very contentious approach to attempt.

Section 4.8 Test

13 out of 15 this week - Gah! got the number of grid boxes in the Hadley Centre coupled model version 3 wrong - not really convinced that demonstrates a greater or lesser level of understanding of the subject. And I needed a second go at answering how far back in time does the validation of climate models run to check the modelled climate matches that of the past? I assumed the point of paleoclimate modelling is to validate our understanding of climate models and feedback mechanisms!
Section 4.9 Reflect

So the main themes this week were climate models are validated and checked, and account for most things we have been able to observe. The second half was about geoengineering, about which I had no previous knowledge. That was all new to me, and very interesting.

I've skipped the running your own model step, but have made a note of the resource URLs and would hope to revisit those pages at a later date.

I think I'm going to make a habit of visiting of the Skeptical Science and Real Climate websites to stay informed about the on-going debates.

Climate Change: challenges and solutions - reflections on week three

Section 3.1 - Video "Signs of Climate Change"

Presented by Prof. Mat Collins (I taught him on a course once - not sure I taught him anything he didn't know already though!).

Key points for me:

• There has been a massive increase in the accuracy and number of measurements of the weather during the 20th Century.
• Lots of analysis shows that both land and sea temperatures both have a rising trend (yearly and decade-to-decade variations still take place though).
• The Arctic polar region has seen the largest rise in temperatures.
• Sea levels have been rising since the 1880's.
• Don't confuse melting sea-ice with rising sea-levels - sea ice is floating and has already displaced the water, it's land ice from glaciers melting that have contributed to this.
• The GOES-R satellite video was rather over-blown - but the satellite program has a web site at http://www.goes-r.gov and a PDF trifold here.

Section 3.2 - Read this Met Office web page about climate change indicators.

Lots of people in the discussions are looking at this page summarising the key indicators, which includes these two images:

and this one:

Section 3.3 - State of the Climate - extreme events - discussion

Pointed us to Cimate.gov extreme weather analysis - the nearest to me (Exeter, UK) was that 2012 was the second wettest year on record for the UK, only narrowly behind 2000.

We were also asked to read this press release from NSDIC which is about Arctic sea ice extent (not as much as in the past, with a 33 year downward trend) and Antarctic sea ice extent (near record extent, due to increased westerly winds in those latitudes making it cooler). 

The fact that 2012 was the second wettest year on record isn't in itself an indication of climate change, but lots of other indicators over a longer period (typically 30 years) provides evidence of climate change.

Section 3.4 - Your warming world

A discussion piece, using the CMIP5 Global Climate Change Viewer

CMIP5 is Phase 5 of the Coupled Model Intercomparison Project

Q. What places on Earth have experienced the largest warming from 1980-2004? 

A. Mean model annual mean temperature rises are greatest over Russia and Canada, the former having some models show a 7 deg. C. increase.

Q. Are the areas that are experiencing the most warming also showing the largest variability in temperature and or precipitation?

A. No, greatest increase in annual mean precipitation appears to be over Papua New Guinea, Ecuador and Indonesia.

Section 3.5 - Urgent Action

Read this statement from the American Geophysical Union.

Q. Having read the statement what would you consider the largest threats to where you live?

A. Living near the coast in South-West England, I think the biggest threats to this area are likely to be the effects of any increases in coastal high waters  - this is very topical at the time of writing with lots of storms and damage to nearby coastal areas taking place, increased rates of coastal erosion and a large proportion of the Somerset Levels being flooded for more than a month now. Some of these may be due to changes in the historical pattern of variability and storminess or increases in the amount of precipitation.

Section 3.6 - Our changing carbon cycle

A video from Prof. Pierre Friedlingstein.

Key points:

10 petagrams of carbon, that's 10 to the power of 16 grams of carbon, are released to the atmosphere every year due to human activities. 

In 2013, the Mauna Loa Observatory in Hawaii recorded a milestone concentration of atmospheric CO2 of 400 PPM, a value not rated over about a million years (Keeling Curve)

90% of the emission of CO2 comes from the burning of fossil fuel

The remaining 10% comes from deforestation. 

For fossil fuel emission of CO2, the main countries emitting CO2 are developed countries, such as USA, Europe, Japan, although emerging countries like China and India are also becoming more and more important. 

For deforestation, the main emitters are developing countries in the tropics such as Brazil or Indonesia. 

The net increase in the atmosphere though is 4.5 petagrams of CO2 per year - the rest is "sunk" over the oceans and land.

Over the deep oceans - more CO2 in the atmosphere means more CO2 in contact with the surface of the ocean, and then for more export of carbon through the deep ocean. This is the largest proportion.

Over land - more CO2 in the atmosphere means more photosynthesis, more plant growth, more biomass, and therefore, more land sinks.

Section 3.6 - Global Carbon Emissions

 Playing with the World Bank data indicator graph tool I drew two graphs.

1. http://data.worldbank.org/indicator/EN.ATM.CO2E.PC/countries/CN-GB-US-IN-BR-AU-DE?display=graph - shows that some developed nations produce significantly more CO2 per capita than others, but these may be falling, but are still way in excess of developing nations
2. http://data.worldbank.org/indicator/EN.ATM.CO2E.KT/countries/CN-GB-US-IN-BR-AU-DE?display=graph - shows that due to the development and large populations of the developing nations, the largest increase in emissions will come from these developing nations.

The conclusion is that to reduce the overall level of CO2 emissions, further reductions will be necessary in developed nations - where the trend is beginning to move in the right direction. But action needs to be taken to stem the growth in emissions per capita in the developing nations.

Reflections on this week

• I got through the material quicker than last week, just two sittings to get through all the sections.
• I was interested in the variety of sources out there on the internet, and the number of tools it is possible to access to play around with the data.
• I got my best score so far in the end of section quiz (14/15).
• I was struck by the number of indicators that all show the same message - the Earth is warming.
• I was prompted to think about the impact of this - and came to the rather selfish view that living in a developed nation we'd probably cope OK with this, it was elsewhere that the effects would be felt the worst.
• Interesting nuggets picked up - melting sea-ice doesn't contribute to rising sea levels and explanations of why the Arctic is getting warmer, but the Antarctic sea ice is becoming more extensive (ice-albedo feedback, and increased wind speeds respectively).
• I'm proud that my blogging skills are getting better with more links and pictures in the blog - I hope you like these!

Climate Change: challenges and solutions - week two

This week I shall compose this blog post as I work through the weeks material. Last week I ploughed through everything in one session - which meant the kids were ignored, didn't do their homework, and had a late tea. This week, I will attempt to pace myself through the material.

Topic for this week: Past climate change - we're looking at both ancient, and more recent natural climate change.

Section 2.1

First off is a video about ancient climate change, and the two conflicting  feedback cycles that act against each other.

One is the fact that the sun is getting brighter, and hence the planet should be warming - but it isn't. This is due to chemical erosion over land, taking carbon dioxide out of the atmosphere in rain, forming carbonic acid, and this then becoming trapped at the bottom of oceans by organisms absorbing this in their shells, and eventually being deposited at the bottom of the ocean as carbonate rocks (sedimentary?). This is a negative feedback loop as the increase in temperature due to the increasing brightness of the sun has been counter-acted by the increase in the rate of weather erosion taking more carbon dioxide out of the atmosphere.

The other feedback cycle explains the concept of "snowball earth", the Earth being on two occasions completely covered in ice. As the polar ice caps extend, the albedo goes up, the earth cools more, until a tipping point is reached (when the ice caps go beyond 30 deg. latitude) and a positive feedback cycle takes place, causing the Earth to cool even quicker. Once the Earth is completely covered in ice though, chemical erosion tails off, and volcanic activity releases more CO2 into the atmosphere, which then starts to heat the planet up again, leading to the end of the "snowball" period.

Section 2.2

The second section this week is a page and series of snippets from an episode of Horizon from 2001 showing the development of the snowball earth hypothesis.

I watched the TV programme in it's entirety.  It was fascinating, showing how the global distribution of "drop stones" in the geological record from 600 million years ago indicated that there been global glacial activity. Mathematics indicated that this was possible, but would have been catastrophic and would have wiped out all life on the planet at that time. Then came the realisation that volcanic activity would continue, pumping out lots of CO2, and a severe greenhouse effect would cause the planet to go from one of it's coldest periods to one of it's hottest. The violence of this change caused extensive deposits of cap carbonate rocks immediately above the levels containing the drop stones - explaining this geological phenomenon. The whole theory was then shot-down by biologists pointing out that an extended global ice-age would have mean the extinction of all life, until it was discovered that certain forms of life are capable of  survival under ice sheets, which would have been formed very slowly, and hence are nearly transparent and free of impurities. The explosion in the evolution of life forms into multi-cell organisms following a sudden end of snowball earth also fits in with this.

A fascinating programme, and I feel I've learn a lot this evening, it't taken a bit more time than I hoped though.

Section 2.3

Exercise to produce some feedback diagrams - I didn't do this, thinking my text above explains this. I looked at a couple of examples posted in the discussions to check my understanding, and registered on the conceptboard web site - but didn't put any time into having a play with this tool (which I think I ought to check out some other time).

Section 2.4

Recent past climate change video with Prof. Dan Charman and Dr. Ewan Woodley.

I liked the fact that parts of this video were on nearby Hound Tor and the Medieval settlement nearby as well as on Exeter University campus.

Main parts of this are - natural variation in solar forcing is due to three factors identified by Milutin Milankovic, these are:

• E - Eccentricity - variation between circular and elliptical of the Earth's orbit - period 100,000 years
• T - Obliquity - variation in the tilt of the Earth's axis - period 41,000 years
• P - Procession - variation or wobble of Earth's axis - period 23,000

Each of these means that the Earth gets different amounts and distributions of solar energy, leading to natural climate variability, and differences in levels of seasonality.

There was a demonstration of taking a tree ring sample, and explanation that aligning these with other tree sources, including those preserved in peat bogs meant it was possible create a climatology going back in time. Reading the transcript it says the last millennia and even further, and that we can recreate variables such as temperature and precipitation - I wonder how? That impresses me!

The next section was about the influence of volcanic activity on the atmosphere. Big volcanic eruptions throw lots of ash and aerosols into the atmosphere, which generally lead to global cooling in the short-term, as seen by the 0.5 deg C drop in temperature following the eruption of Mt. Pinatubo in 1991.

Then pulling it all together - these factors explain the main causes in climate variation, but don't explain what has happened in the last 100-150 years - when man-made CO2 has been pumped into the atmosphere.

Section 2.5

Was some recommended reading to answer one of the following 6 questions:

1. What are climate change records?
• The Met Office has a useful link summary 


A mixture of direct measurements - which need to be quality controlled for biases in the methods and tools used, plus "proxies" which are other measurements that can be used to infer properties of the climate. E.g. tree rings, coral growth, ice cores and temperature profiles of oil-drilling holes.


2. How do volcanoes affect climate change?
• NASA’s Earth Observatory website link
3. How is today’s warming different from the past?
• NASA’s Earth Observatory website link 
4. What is the role of isotopes in determining temperatures from the past?
• NASA’s Goddard Institute for Space Studies link
5. How have trees been used to reconstruct different climate variables across the world?
• Science of Tree Rings website link
• This page outlines the main principles of dendrochronology, and even provides an answer to my question above... the trees/wood sampled is chosen such that it most sensitive to the environmental factor that you want to measure. E.g. to measure the variation in the amount of precipitation trees that will suffer most in droughts are selected, i.e. those on rocky ground or hill edges, their tree rings will vary the most with the amount of rain in a season. These are "proxies" and the full record is constructed by collating with periods with measurements available. There is also the principle of crossdating to line up one time period so that it overlaps with another, hence a longer record is made up.
6. How can ice cores provide a record of atmospheric composition?
• NASA’s Earth Observatory link

Section 2.6

400 parts per million - discussion about crossing this threshold. Didn't participate, again due to time pressures!

Reflection

1. What are the most important themes you have learned this week?

Wow, I feel we covered a lot of material this week, but I learnt a lot about the natural causes of global climate variability, and was introduced to a number of concepts that I wasn't previously familiar with, such as "snowball earth", the long-term carbon cycle (I was previously under the impression this cycled through vegetation and fossil fuels only, not aware of the significance of chemical weathering), and the explanation of the three types of variation in the movement of the Earth around the sun.

2. What aspect of this week did you find difficult?

I deliberately set about do this in little chunks rather than in one go this week, and seem to have spent about two or three times as much time on it as last week, definitely exceeding the 2-3 hours I thought I'd signed up for! I've had a really busy week, so there were moments when I didn't know if I was going to get it all done. Having said that, I've made some time for other things, and maybe writing these rather extensive notes is a bit of overkill. Not sure what my approach to week three will be.

3. What did you find most interesting? and why?

The Horizon episode was simply fascinating - I knew nothing of the concept before, and loved the way the programme was constructed. Particularly with new theories and evidence countering those theories leading to an evolution in the theory - I suppose this is a demonstration of the scientific method.

I also enjoyed reading the article on dendrochronology - mainly because it answered some questions that sprung to my mind whilst watching the video. I'd always knew this was done, just not how.

The long-term carbon cycle was also new to me, so that was a key thing learnt this week.

4. Was there something that you learned this week that prompted you to do your own research?

Well, I've had a quick read up on chemical weathering here.

5. Are there any web sites or other online resource that you found particularly useful in furthering your knowledge and understanding?

Haven't ventured that far looking due to lack of time.

Summary for the week: learnt lots of new stuff and as an aside, I also realised that although I did Geography O'Level, I've never had any exposure to Geology in any previous learning context, so maybe that's something I should learn about some time in the future.

Links to external documents used this week:

BBC video about snowball Earth - http://www.bbc.co.uk/nature/ancient_earth/Snowball_Earth and a full episode of Horizon from 2001 showing the development of the hypothesis is available on Youtube here http://www.youtube.com/watch?v=ydLNrTzMIgc

Articles I've read this week of related interest:

http://www.theguardian.com/business/2014/jan/15/bp-predicts-greenhouse-emissions-rise-third