Week 7 Reflectons

The thing from this week that I found most poignant was the discussion about NIMBYism. The way we produce and use our energy has to change. There are so many good arguments on both sides of the discussion. I think that slowly attitudes will change to renewable energy provision, as people understand just how important it is to protect our environment. Large scale constructions of wind farms can benefit a large number of people, but may have negative and immediate consequences for a few. These people’s opinions need to be taken into account, but we can’t lose sight of the bigger picture. The renewable energy industry is still relatively new and is always growing and inventing new, more efficient ways to harness energy from the world around us, with the minimum of intrusion into people’s lives. We need to embrace the change in our energy consumption and see eg windfarms, not as a blight on the landscape, but as evidence that we care about our environment.

Drewsteignton, Devon

There are great innovations to be found in the way we build our homes and public spaces. I think the use of these designs in schools is particularly important. As the materials and methods become more standard-place and cost effective I hope that their use will increase and we can build our homes to last. There is a shortage of housing in this country already. Building these types of houses will cost more, but surely, if they can withstand the changes in the climate that are coming, won’t it be worth that extra expense?

7.6 NIMBYs in Action

Search for a local campaign group in action near you. What are the main arguments of the local campaign group you have discovered? Share a link to their website in the discussion.

I live in Devon. Renewable energy is a controversial topic around here. On one hand we have loads of coast line in the South West and large areas with very few people living in them. I’ve found one example of a campaign group, Campaign To Protect Rural England, Devon. It is supportive of the odd wind turbine that supports one farm, but on a very small scale which will affect no one but the land owner. It is against any large scale wind farm, solar farm etc. I can understand that Devon is a beautiful are and it is this fact that draws an international crowd of visitors every year. The unspoiled landscape and views this county offers is the very thing that so many residents earn their living from. In another article from a local newspaper, the Western Morning News, they do talk about how renewable energy projects create jobs, unemployment being a big issue in rural areas.


I can understand the CPRE objection to projects. I agree that we can’t go putting big wind farms everywhere, for reasons that they mention, and I have put above. But, surely if we don’t do something to slow down climate change, Devon is going to be a very different place anyway. If we really want to protect rural England, surely we have to try with every effort to mitigate the effects of climate change?

See also their publication: Renewable Energy in the Countryside: Rewards and Risks

Photos by me of pretty South Devon coastal areas.

7.3 Building design near you

This is a classic Devonshire farmhouse, UK. Its main construction period was somewhere around 1600 (but probably the first small building was earlier, then added to). I can pretty much guarantee, in that case, that very little thought to future climate change was put into its design.

There are a few things it has that will work well in the changing climate. It is made from cob, a mixture of subsoil and straw. Probably dug from the land right next to the building (why so many old cob houses have a pond…). It’s an interesting idea for future housing. Very little energy is used in the transport of the materials. They are natural and don’t produce as much CO2 as concrete production. The walls are very thick, up to 1m in some places. It stays cool all year. The thatched roof is a very good insulator, both in keeping heat in in the winter and out in the summer. It’s a hard-wearing, long-lasting material.

However, it could certainly do with some modifications if it was build new today. The windows need to be much larger to allow natural light in. This would reduce energy needed in lighting. With energy efficient windows this would now be viable (not so in 1600). It could also do with some form of heating beyond wood-burners! Planning laws limit the adaptation of such buildings to the future climate, as well as cost, of course.

I think ideas could be drawn from some of the traditional building methods. Coupled with more modern technologies for window, heating and roofing they could have a place in the future building industry. This particular method does require a lot of space, so not suited well to an urban area.

Week 6 Reflections

I was surprised at just how much the temperature difference can be within a city, and how deadly the results can be during a heat wave. I found the ways of mitigating this very interesting, the different technologies employed, both simple and more complicated. It’s an interesting cycle.

The problems affecting future food production were complex and the investigation of the inter-weaving systems and balances between population, food production and a shifting climate kept me delving into the subject. It was a good introduction to the subject for me.

There are a number of interesting website I found along the way…

• https://www.dosomething.org/facts/11-facts-about-education-around-world
• http://www.agmrc.org/renewable_energy/renewable_energy/can-we-meet-the-worlds-growing-demand-for-food/
• http://www.epa.gov/heatisld/index.htm
• http://www.theguardian.com/global-development/food-security
• http://www.who.int/trade/glossary/story028/en/

6.5 Tackling food security

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

I think this problem has two sides from which to tackle it. A combination of both would probably work best. One is to increase the quantity of food produced in order to feed a growing population. Another is to slow the growing population. Whilst increasing food production would require a major effort and organisation and use of technology, it is a relatively simple concept. Decreasing the rate of population growth, however is a very different problem. I don’t believe people should be limited to how many children they have. I think it should be up to the family itself. There is one way, though, that has so many beneficial side effects with it, and I will discuss it below.

Here are my 3 subjects that will help be a part of the solution to the problem.

1. Eat less meat. The land area given to grazing is huge. It impacts on the world’s forests. The production of red meat produces a lot of greenhouse gasses. By cutting down our global meat consumption we could give over the land to a different kind of farming.

2. Efficiency of food production and storage. There is a lot of research going into the way we grow crops. From the use of pesticides and fertilisers to genetically modifying crops to be more drought resistant. Improvements in the methods of storage of grains post-harvest may also help reduce wastage.

3. Educate women. This is from the other side of the problem. It has been shown that women who have been educated have fewer children. Obviously I’m all for educating boys too, but it’s the education of girls that seems to have this effect of decreasing birth rate. There have been some very interesting studies. The results also show greater economic benefits and health benefits for the whole family.

It is such a difficult subject and has implications on human rights, land use and international cooperation. But estimates show it is possible. Maybe we all just need to change our expectations of what we can eat.

References

Meeting demand for food article

Population Reference Bureau

Birth Rate ref 1

Birth Rate ref 2

6.2 Urban Heat Islands

The NASA website provides an excellent summary of urban heat islands. How do you think the land use planning in urban heat islands could be used to reduce the scale of such islands?

Heat is trapped in urban areas for a number of reasons. These mostly boil down to:

1. Lack of convection, which would distribute the heat. This is caused by tightly packed, high-rise buildings that trap air at street level.
2. Lack of evaporation. The impermeable surfaces that cover our cities and the efficient water drainage systems reduce the effect of heat loss through evaporation.
3. Heat absorption. The buildings, roads and pavements absorb heat during the day, releasing it at night, keeping the temperature high.
4. High pollution levels/ released heat from air conditioning systems.

So, to reduce this, planners might want to think about:

1. Lower-rise, more distributed buildings (obviously this has big spatial and financial implications in itself, as it would take up a lot more area, so not really practical).
2. More lakes, parks and trees. These all help with the evaporation of water and parks are proven to be cooler than the surrounding built-up areas. Also using, for example, permeable paving, which has many benefits, but costs vary a lot.

These pictures of Baltimore show the surface temperature (top) where the darker the colour, the cooler it is, and the level of development (bottom) where red is highly developed and white is low development/green space. note where the parks in the city are... The full details can be found on the Earth observatory site HERE.

3. Paint roofs white, or use reflective roofing, which would reduce the radiation hitting the building. Or green roofs, which are fantastic for so many reasons. (Exeter Uni has these at Tremough). Rooftop gardens would also help and create a lovely space for residents…
4. We can all try to reduce emissions in cities. Plus, the use of some of the above mitigation methods would start the cooling, and then we wouldn't have to use the a/c so much, therefore pumping less warm air into the neighbourhood, reducing the problem further!

Sorted!

Week 5 Reflections

I found this week to be so interesting. Two very different topics both relating to the ocean. The rate of ocean acidification is really scary. It throws up a lot of questions about the future stabilities of ocean life and what consequences will come of these interruptions in the early life stages of some of the smaller organisms. Dr Ceri Lewis is an inspiration. Obviously very dedicated to her work and has great enthusiasm.

The influences on the ice sheets and how the flow of glaciers happens was eye-opening. I loved the video link to the team in the Himalayas. I thought the series of photographs and the guys passion for his project very inspiring.

Both themes this week show just how devastating some of the potential results of climate change can be. I have put up a few links in one of my posts a couple back. I’m intrigued about how the sea levels will rise unevenly around the globe and want to look into that a bit more.

Thanks again all involved.

5.7 The Impact of Ocean Acidification

Ocean acidification has enormous implications for the functioning of natural systems. However, its human impact cannot be overlooked either. Engage with your peers in the discussion below to answer these two questions:

I got involved in the discussion but I also wanted to post here. WARNING - I don't seem to have anything very positive to say about these subjects this week...

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

The acidification is happening at an unprecedented rate. pH levels have, historically, been as low as those predicted in the future. But the change was gradual. Species had time to adapt to the altered habitat around them. They had time to evolve. What we are seeing now does not allow for that. As the bottom of the food chain falters the consequences will make their way through to the larger species, rendering our oceans, eventually, unrecognisable.

2. 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?

A rising sea level affects coastal communities around the world; approximately 150 million people live within 1 meter of current sea level. And that’s not taking into account any increase in future population. Think of the displacement of people this would create. A greater density of people, an instable climate in which farming is uncertain. We would need to harvest food from the sea. It’s quite possible that, given our current fishing crisis there would be a shortage. Then, if you take out of the equation the animals that would be unable to reproduce in an acidified ocean, we can say that we’re left with a whole lot of problem. I think the two are going to happen simultaneously. How can we separate the two?

5.4 Calving events

How might processes like ocean and atmospheric warming cause mass loss from calving to increase? What do you think are the key controlling processes? 

There is some really interesting reading about this subject. The dominant discussion seems to be in the effects of a warming ocean. Greenland and the Western Antarctic Ice Sheet come up frequently as the two main ice sheets that Glaciologists are concerned about. Greenland is warmer, in general, than the Southern polar region, so may be more sensitive to change. Below are some examples of how the ice sheets are being affected, and ways in which calving rates could increase.

Thermal Expansion. In the past one of the major factors affecting sea level rise has been through thermal expansion of the oceans. This is still true, but as global temperatures rise this will be reflected in ever rising sea levels.

Ice-shelves. These are the ice sheets that extend over the ocean. It's the first line of defence and the area where calving happens most frequently. As the sea temperatures rise, the ice shelves are warmed from underneath. This would cause them to break up more readily. Large icebergs would form and drift out to sea. However, the water trapped in the ice shelves is already accounted for in sea level measurements, so these events would not really cause any rise. The danger comes because some of these ice shelves act as buttresses to greater quantities of inland ice. If this inland ice was left unsupported it could flow to the edge of the oceans, calve away and contribute to sea level rises. There are particular fears of this in the Western Antarctic Ice Sheet.

Precipitation: A warmer climate encourages the uptake of water vapour into the atmosphere, which then falls as precipitation. Snow, in the polar regions. The three reasons behind this are 1. Warmer air can carry more moisture; 2. Warmer waters means more evaporation; 3. Reduced sea ice means more of the ocean is uncovered, so, again, more evaporation. This would, seemingly, lead to an increase in ice cover... However observations seem to be showing that the balance is in favour of the loss of ice cover.

Basal lubrication. There seem to be conflicting and changing discussions around this issue. A study, using computer models based on observations during fieldwork in Greenland from The University of Bristol revealed that by the year 2200 lubrication would only add a maximum of 8mm for that year to sea-level rise – less than 5% of the total projected contribution from the Greenland ice sheet.

Lead author, Dr Sarah Shannon, from the University of Bristol, says,

 “This is an important step forward in our understanding of the factors that control sea-level rise from the Greenland Ice Sheet. Our results show that melt-water enhanced lubrication will have a minor contribution to future sea-level rise. Future mass loss will be governed by changes in surface melt-water runoff or iceberg calving.”

“We found that the melt-water would lead to a redistribution of the ice, but not necessarily to an increase in flow.”

There is also a hint of a discussion on why sea level rise is not uniform across the globe, which is fascinating. It suggests that the regions affected first will be around the poles and then “slosh” from Antarctica. The Northern hemisphere will experience the greatest sea level rise and it may actually fall, eventually, around Antarctica.

Antarctica’s ice sheet has been called the ‘sleeping giant’ of sea level, but it’s beginning to stir. Everything we've seen about this change points to human influences on climate – and now we’re at the point where human actions will be needed to stop it. - Dr Ted Scambos


Refs

http://www.aip.org/history/climate/floods.htm
http://earthobservatory.nasa.gov/Features/PolarIce/polar_ice2.php
http://www.theguardian.com/environment/climate-consensus-97-per-cent/2014/may/30/global-warming-vulnerability-greenlands-ice-sheet
http://www.nature.com/articles/ngeo2167.epdf?referrer_access_token=L-oQy7WT-LAYYF8pZ4wR9tRgN0jAjWel9jnR3ZoTv0Pf_LUEqgO1ubFbW_Fvq0s81-HZKnVEK146NaEKgjYtU12w1TH8UO27_Yo_2CBKt-I%3D
http://www.theguardian.com/environment/climate-consensus-97-per-cent/2015/jan/14/antarctic-ice-sheet-a-sleeping-giant-beginning-to-stir

http://www.ice2sea.eu/2013/08/12/pr2013_09/

Week 4 Reflections

This week has been a very interesting look at climate models and geoengineering. Depending on the scenario entered into the climate models, the future predictions of temperature, extreme events and even an acute change in the patterns of the ocean currents, can have some wildly different results. The predictions tested on past observed and modeled changes show that human actions have caused the changes in the latter half of the century. (IPCC 4th report “There is at least a 90% chance that the observed increase in temperature globally is due to man-made greenhouse gases”.)

Photo I took of some bluebells last year, near where I live, just for fun and prettiness.

I found the huge debate around geoengineering very interesting. It is a broad-reaching topic and arguments are based on both scientific reasoning and ethical beliefs. I understand its controversy. Leaping in with this technology without really understanding the baseline problem, or without first doing what we can to mitigate to rise in greenhouse gases in a more long lasting and sustainable way is simply not going to work. There have been some great analogies I have read!

It's been an interesting introduction to things like the SPICE project.

These technical solutions should be consigned very much to the “Plan B” heading, in my opinion. A very thought-provoking week. Thank you.

4.7 Should We Geoengineer Our Climate?

What is your view on geoengineering? Should it be used to prevent our planet warming? Post your views into the discussion.

There are a number of arguments, both for and against geoengineering, which are backed up by valid evidence and opinions. Firstly, there is the general acceptance that, yes, the Earth is warming, and to a greater extent than can be explained by natural background climate fluctuations. I think we can generally agree on this. There is also strong evidence that the cause of this warming is an increase of “greenhouse” gases, and that this increase is cause by anthropogenic factors, ie us. We are burning fossil fuels at a huge rate, deforesting vast areas of the planet and generally pumping gases like CO2 into our atmosphere. The predictions of what effects these changes are likely to have are all different, depending on the scenario they are based upon, but none of them are good. They point to more severe droughts, more intense flooding and a huge loss in biodiversity as a result.

So what are the answers? How should we respond to this? We obviously have to do something. it would be lovely to believe that the world could quickly cease to use fossil fuels, that all power could be harnessed from renewable sources. Geoengineering is another option. I agree with the majority of the scientific community who have commented on this field (as far as I can tell, that is) that we should be exploring these options, but with the hope that they will never have to be deployed. it shouldn't take us off track to find better, more fundable, longer lasting solutions. The implementation of geoengineering, even of research projects, does of course come with its own huge bundle of problems regarding ownership, funding and profits, let alone what adverse effects it might have. But surely we can’t answer the question without at first trying to gather as many facts about it as possible? Below is a quote from the forward of “Geoengineering The Climate”, written by Martin Rees, the president of the Royal Society in 2010, which I think sums up the argument quite well.

“The continuing rise in the atmospheric concentration of greenhouse gases, mainly caused by the burning of fossil fuels, is driving changes in the Earth's climate. The long-term consequences will be exceedingly threatening, especially if nations continue 'business as usual' in the coming decades. Most nations now recognise the need to shift to a low-carbon economy, and nothing should divert us from the main priority of reducing global greenhouse gas emissions. But if such reductions achieve too little, too late, there will surely be pressure to consider a 'plan B' to seek ways to counteract the climatic effects of greenhouse gas emissions by 'geoengineering'.

Many proposals for geoengineering have already been made but the subject is bedevilled by much doubt and confusion. Some schemes are manifestly far-fetched; others are more credible, and are being investigated by reputable scientists; some are being promoted over-optimistically. In this report, the Royal Society aims to provide an authoritative and balanced assessment of the main geoengineering options. Far more detailed study would be needed before any method could even be seriously considered for deployment on the requisite international scale. Moreover, it is already clear than none offers a 'silver bullet', and that some options are far more problematic than others.”

4.6 Are Ideas to Cool the Planet Realistic?

Geoengineering seems to be one of those topics that no one can really agree on. Should we be considering it at all? Or by doing so are we accepting that we can’t reduce our greenhouse gas emissions and we are simply giving up? There are two sides to this debate, each bringing with it their own arguments and problems.

The main ways in which this technology would be used to mitigate the effects of global warming are:

1. Carbon Dioxide Reduction. These methods aim to reduce the quantity of CO2 in our atmosphere (afforestation, ocean fertilisation).
2. Solar Radiation Management. These are ways in which to reflect more of the sun’s radiation back into space, counterbalancing the increase in greenhouse gases (release of sulphate particles into the atmosphere, cloud whitening).

There are a number of major caveats in the use of these, brought up by a number of questions. Who owns them? Who has the financial benefits? What if they fail?

The technology is possible, the effects might mitigate the warming due to CO2 emissions. But do we want to consider them yet? Perhaps we should research them, because surely it’s always good to have all the information, but with strong governance from a globally representative body.

Using these methods will have side effects detrimental to many regions on the globe, but letting things continue as they are will also have possibly devastating consequences. The real answer is we all need to take responsibility to reduce emissions as individuals, businesses and countries. But how likely is that?
(sorry about the unhappy final note)

REFS:
Various Guardian articles
BBC

The Keeling Curve

Came across this and thought it was interesting. It's from this website.

4.4 Predicting Climate Change

In short, the projections made by climate models have generally been proved correct by real data. Depending on the scenario on which the prediction is based (see below) the outlook is not very good…

The Executive Summary, part of the Introduction to the IPCC Fifth Assessment Report provides a very concise roundup to the predictions, observed recordings and the modelling behind the report. It’s definitely worth a read.

An example of an article in the general Press is here, from the Guardian last July. It discusses the accuracy of climate model predictions and the possible reasons to explain differences in predicted climate and actual climate, when these have been present. It is based upon a paper led by James Risbey in Nature Climate Change, which “takes a clever approach to evaluating how accurate climate model temperature predictions have been while getting around the noise caused by natural cycles”. 

Projections are run for different scenarios for the climate. Each can have a very different outcome. Here are some examples of different scenarios from the IPCC and their predictions for effects on temperature and sea level rise. These are taken from the IPCC Fourth Report in 2007. Each report is based on slightly different data which alters as the technology gets better and more accurate.

Table SPM.3. Projected global average surface warming and sea level rise at the end of the 21st century. {10.5, 10.6, Table 10.7}

	Temperature Change		Sea Level Rise)
	(°C at 2090-2099 relative to 1980-1999)a		(m at 2090-2099 relative to 1980-1999)
Case	Best estimate	Likely range	Model-based range excluding future
			rapid dynamical changes in ice flow
Constant Year 2000 concentrationsb	0.6	0.3 – 0.9	NA
B1 scenario	1.8	1.1 – 2.9	0.18 – 0.38
A1T scenario	2.4	1.4 – 3.8	0.20 – 0.45
B2 scenario	2.4	1.4 – 3.8	0.20 – 0.43
A1B scenario	2.8	1.7 – 4.4	0.21 – 0.48
A2 scenario	3.4	2.0 – 5.4	0.23 – 0.51
A1FI scenario	4.0	2.4 – 6.4	0.26 – 0.59

MULTI-MODEL AVERAGES AND ASSESSED RANGES FOR SURFACE WARMING

Figure SPM.5. Solid lines are multi-model global averages of surface warming (relative to 1980–1999) for the scenarios A2, A1B and B1, shown as continuations of the 20th century simulations. Shading denotes the ±1 standard deviation range of individual model annual averages. The orange line is for the experiment where concentrations were held constant at year 2000 values. The grey bars at right indicate the best estimate (solid line within each bar) and the likely range assessed for the six SRES marker scenarios. The assessment of the best estimate and likely ranges in the grey bars includes the AOGCMs in the left part of the figure, as well as results from a hierarchy of independent models and observational constraints. {Figures 10.4 and 10.29}

Week 3 Reflections

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

This week was in interesting look into the anthropogenic factors affecting climate change. The ratio of the release of CO2 emissions through the burning of fossil fuels compared to deforestation was different to that I expected. 90% through emissions was higher than I thought. I think one of the biggest themes this week was how countries differ in their CO2 production, but how each contribution has an effect globally.

2. What did you find most interesting? And why?

I was interested in the topic of carbon sinks. It brought up questions such as ‘how is the huge amount of carbon being trapped by the ocean affecting it?’ and ‘will there come a point when these sinks are “full” and cannot absorb so much carbon? What then?’ I hope this course will return to these subjects. It’s something I would like to know more about.

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

A mentioned above, I want to know more about carbon sinks. I will see if they come up in future weeks, but I will be looking into it!

I've just watched the Feedback for this week. Thank you!

3.7 Global carbon emissions

The World Bank publishes a variety of environmental data, including carbon emissions (measured in kt). Create a graph to show a variety of countries at different levels of economic development by following this link to the World Bank web site. Include the USA and China in your graph. Share your graph in the discussion. You may also want to try plot carbon dioxide emissions measured in metric tons per capita. What conclusions can you draw?

This is a fascinating insight into the CO2 emissions globally. I have kept my graph simple for now, looking at some of the major players in the economic and emissions group.

It’s interesting to see how the graph and the picture it portrays changes whether you view the graphs for CO2 emissions per country or per capita.

CO2 emissions (kt)

Data from World Bank

CO2 emissions (metric tons per capita)

Data from World Bank

3.5 Urgent Action

What would you consider the largest threats from extreme weather events to where you live?
The American Geophysical Union (AGU) is a union of scientists dedicated to enhance the understanding of geophysical science.
Follow this link to the latest statement on climate change which was released in August 2013 and is titled Human-induced Climate Change Requires Urgent Action. The statement refers to some of the observations introduced in this week’s lesson including increases in air temperatures, sea level and reductions in Arctic sea-ice. What other examples are included in the statement?
The statement also includes climate projections, which we will introduce next week. Having read the statement what would you consider the largest threats to where you live? Post your responses in the discussion below.

The summary report also mentions the increase in sea temperatures and atmospheric water vapour, the decrease in areas of glaciation, snow cover and permafrost, as well as seemingly counterintuitive changes such as regional cooling. These changes will in turn have an effect on the weather patterns globally.

In the UK we are probably most likely to be affected by a change in seasonal weather patterns. As seen in previous links this week the UK is predicted to have wetter, warmer winters, and possible summer droughts. This would have strong implications on the farming industry of this country. We have seen the effects that such weather has on crops and the country’s infrastructure.

The report mentions that the melting of arctic ice could occur more rapidly than predicted. A rise in sea levels would affect a number of countries, globally, in some cases with devastating consequences. Europe has a lot of low-lying areas which could become affected by this, including the East of the UK.

3.3 State of the climate: extreme events

Follow this link to major climate events created by Climate.gov, then select 2013 and find the nearest major climate event listed to where you are now. Does this provide further evidence of climate change or does it add more complexity to the issue?

The major climate events shown on the map show that in subsequent years there can be a “warmest on record” event, followed by a “coldest on record” one. This shows that there are changes happening. Climate change does not necessarily mean warming of every area on the planet. Changes in weather patterns can affect the climate in a number of ways, some of these having cooling effects.

The example given is the record extent of sea ice in the Antarctic. At first glance this could be taken for good news, it’s not melting! However researchers attribute this to a change in the weather system to the North, which increase the winds across Antarctica. These increase winds actually cool the continent, increasing the sea ice. It is a seemingly counter intuitive result of warming in other regions, showing that climate change works on a global scale, as well as in microclimatic events.

Refs:
http://www.climate.gov/news-features/featured-images/state-climate-extreme-events
http://nsidc.org/news/newsroom/20121002_MinimumPR.html

Week 2 Reflections

1. What are the most important themes you have learned this week?
This week has been an interesting introduction to paleoclimatology. The long-distant changes in the Earth’s climate over its history and how we are able to read these changes in the evidence of rocks, trees and sediments.

2. What did you find most interesting? And why?
I found the idea of the ‘snowball Earth’ fascinating; the feedback mechanisms that can allow such an event to occur, and the processes that reverse it. I found the aspect of there being a ‘tipping point’ of ice cover very interesting, and how that separates this phenomena from an ice age.
I also liked learning about the different methods of being able to ‘read’ the climate history of the Earth.

3. Was there something that you learned this week that prompted you to do your own research?
As discussed in Q2 I found the ‘Snowball Earth’ interesting. The links provided were very useful and yielded an ongoing path to more about the subject.

Week 2. 400ppm

Understanding past climate changes can be key to understanding the state of the climate in the future. On May 9, 2013, carbon dioxide levels in the atmosphere reached the level of 400 parts per million (ppm). The last time the Earth experienced this level of carbon dioxide was in the Pliocene about three to five million years ago. Investigate what the temperatures were during this time period and compare them to today. Using your knowledge from the course so far, what could explain the changes?

During the Pliocene CO2 levels were at a similar level of today. It is thought that a lot of the differences between the Earth then and now were due to the feedback loops discussed last week.

For example, there was significantly less ice both at the poles and on the mountain ranges. This ice albedo loop keeps the temperatures high.

The distribution of heat around the globe was very different. A few degrees shift in temperature has a great effect on the Earth’s oceans and the currents. The change in the sea surface temperature (SST) particularly affected the higher latitudes. These were much warmer than they are today, although the temperatures around the tropics were quite similar.

The comparison with the Pliocene is important because it is one of the few times we can compare climates (then and now) where there are similar taxa living. We can therefore derive some implications for consequences of increasing global temperatures today.