I answered Q5 Why is the Arctic experiencing the largest warming on Earth? correctly but I feel it is something of a simplification. The loss of sea ice is clearly a driver of what Prof. Peter Wadhams refers to as the Arctic ice death spiral. However, something must kick-start the process that results in the initial loss of sea ice.
The recent paper The central role of diminishing sea ice in recent Arctic temperature amplification (Screen & Simmonds 2010) which I found via Skeptical Science goes into more detail. The full paper is available here.
In the past, I had the good fortune to hear a talk about sea ice by Prof. Grae Worster. Unfortunately, I forget the details but there is a great deal of complexity in something as simple as the freezing of salty water! There is a paper here and here is the remarkable 'Brinicle' ice finger of death filmed in Antarctic http://www.bbc.co.uk/nature/15835017.
I attended two talks on climate change this week: "Climate Change and Migration", Alex Randall, Climate Outreach Information Network and and the third in the Adaptation to climate change seminar series by Professor Charlie F Kennel. The latter referred to http://www-ramanathan.ucsd.edu/files/pr196.pdf. Short Lived Climate Pollutants (SLCPs) were discussed as a short term adaptation strategy and to refresh the stale climate dialogue centred on carbon.
Thursday 30 January 2014
Week 3 - Global carbon emissions
My chose countries were: China; United Kingdom (home); United States; India (lower middle income); Qatar (rich); Maldives (Pacific island nation); and Congo, Dem. Rep. (poor).
Estimates for rich and poor countries used data from Wikipedia.
Here's my graph.
Here's the same countries showing carbon dioxide per capita on this graph.
The second graph shows the massive differences between the richest and poorest countries. There is a slight drop in the United States and the United Kingdom, possibly as a result of the recession or the transfer of manufacturing to China which shows a steady rise.
However, the per capita results don't show the inequalities within countries. As inequalities grow, as in the United Kingdom, it is likely that the individual carbon dioxide emissions of the poorest will be reducing as they struggle to balance bills for heating and eating while the lifestyles of the richest will result in higher emissions.
Estimates for rich and poor countries used data from Wikipedia.
Here's my graph.
Here's the same countries showing carbon dioxide per capita on this graph.
The second graph shows the massive differences between the richest and poorest countries. There is a slight drop in the United States and the United Kingdom, possibly as a result of the recession or the transfer of manufacturing to China which shows a steady rise.
However, the per capita results don't show the inequalities within countries. As inequalities grow, as in the United Kingdom, it is likely that the individual carbon dioxide emissions of the poorest will be reducing as they struggle to balance bills for heating and eating while the lifestyles of the richest will result in higher emissions.
Tuesday 28 January 2014
Week 3 - Urgent Action
I live in Cambridge, about 70Km from the sea and my house is just over 10m above sea level. Most of the fenland between my house and the sea is much lower.
The most recent example of an extreme weather event near me was the winter storm of 5 December 2013 when a combination of low atmospheric pressure, high tides and strong winds caused a major storm surge in the North Sea. Fortunately, I was not directly affected. Such storms can impact road, rail and electrical power distribution in addition to flood damage.
Another potential extreme weather event would be a prolonged summer heat wave like the one in 2003 which caused over 14,000 heat related deaths. Very few homes in the UK have air conditioning and are unprepared for such conditions.
The most recent example of an extreme weather event near me was the winter storm of 5 December 2013 when a combination of low atmospheric pressure, high tides and strong winds caused a major storm surge in the North Sea. Fortunately, I was not directly affected. Such storms can impact road, rail and electrical power distribution in addition to flood damage.
Another potential extreme weather event would be a prolonged summer heat wave like the one in 2003 which caused over 14,000 heat related deaths. Very few homes in the UK have air conditioning and are unprepared for such conditions.
Week 3 - Your warming world
My country is the UK.
For temperature, the mean model and almost all of the individual models the future projection for 2050-2074 is several degrees higher than the observations for every month.
For precipitation there is not such a strong agreement among the models. The mean model future projections are for similar or higher values in winter months and lower values for summer months.
As I live in East Anglia an area with limited natural water supplies and high demand from agriculture lower precipitation in summer could cause water supply problems.
The places that have experienced the largest warming from 1980-2004 are the high northern latitudes, particularly northern Russia and the Arctic.
Using Svalbard as an example there is a variability of around three degrees in observed temperatures during the winter months dropping to around one degree during the summer months.
Again, using Svalbard as an example there is low variability on the precipitation observations, typically plus or minus 0.1mm per day on a total of 0.9mm to 1.7mm per day.
So from the above, it appears that areas that are experiencing the most warming also showing large variability in temperature but not in precipitation.
For temperature, the mean model and almost all of the individual models the future projection for 2050-2074 is several degrees higher than the observations for every month.
For precipitation there is not such a strong agreement among the models. The mean model future projections are for similar or higher values in winter months and lower values for summer months.
As I live in East Anglia an area with limited natural water supplies and high demand from agriculture lower precipitation in summer could cause water supply problems.
The places that have experienced the largest warming from 1980-2004 are the high northern latitudes, particularly northern Russia and the Arctic.
Using Svalbard as an example there is a variability of around three degrees in observed temperatures during the winter months dropping to around one degree during the summer months.
Again, using Svalbard as an example there is low variability on the precipitation observations, typically plus or minus 0.1mm per day on a total of 0.9mm to 1.7mm per day.
So from the above, it appears that areas that are experiencing the most warming also showing large variability in temperature but not in precipitation.
Monday 27 January 2014
Week 3 - State of the climate: extreme events
I live in Cambridge, in the UK, so my nearest major climate event for 2012 was described as After experiencing dry conditions during the first three months of the year, the remainder of the year was wet, resulting in the second wettest year on record, behind 2000.
These lecture notes from the University of St. Andrews explain how warmer air can hold more water.
The UK is a collection of islands off the eastern coast of Europe. Depending on wind conditions its weather can be influenced by the Atlantic ocean or continental Europe. Hot dry winds from the east can result in drought. Warm wet winds from the west can product heavy rainfall in western areas especially where the air rises over hills and mountains.
It is difficult to like a single extreme event to climate change. However, if a trend is observed over decades then that strongly suggests that there may be a connection.
Unlike the Arctic which a frozen sea of ice formed from salt water, Antarctica is a continent covered with fresh water ice from precipitation which spreads out as ice sheets over the surrounding oceans. There are two key measures of sea ice: extent and volume.
For extent if the area covered by ice exceeds a threshold (typically 15 percent) it is counted towards the extent otherwise it is excluded. This is relatively easy to measure from satellite or aircraft photographs.
Sea ice volume also requires ice depth information. Modern satellites such as The ESA CryoSat 2 can measure sea ice (and land ice) volume.
The paper Satellite observations of Antarctic sea ice thickness and volume discusses the period 2003-2008 and observes that Sea ice thickness exhibits a small negative trend while area increases in the summer and fall balanced losses in thickness leading to small overall volume changes.
The web page Antarctica's ice loss on the rise discusses the three years from 2010 and observes the West Antarctic Ice Sheet is losing over 150 cubic kilometres of ice each year. This includes ice beyond the grounding lines which is floating on the sea.
The suggested web page Press Release: Arctic sea ice shatters previous low records; Antarctic sea ices edges to record high suggests that the Antarctic changes are due more to wind than warmth.
It is possible that the increased Antarctic ice extent could be due to wider distribution of thinner ice and could still represent a loss of sea ice volume.
These lecture notes from the University of St. Andrews explain how warmer air can hold more water.
The UK is a collection of islands off the eastern coast of Europe. Depending on wind conditions its weather can be influenced by the Atlantic ocean or continental Europe. Hot dry winds from the east can result in drought. Warm wet winds from the west can product heavy rainfall in western areas especially where the air rises over hills and mountains.
It is difficult to like a single extreme event to climate change. However, if a trend is observed over decades then that strongly suggests that there may be a connection.
Unlike the Arctic which a frozen sea of ice formed from salt water, Antarctica is a continent covered with fresh water ice from precipitation which spreads out as ice sheets over the surrounding oceans. There are two key measures of sea ice: extent and volume.
For extent if the area covered by ice exceeds a threshold (typically 15 percent) it is counted towards the extent otherwise it is excluded. This is relatively easy to measure from satellite or aircraft photographs.
Sea ice volume also requires ice depth information. Modern satellites such as The ESA CryoSat 2 can measure sea ice (and land ice) volume.
The paper Satellite observations of Antarctic sea ice thickness and volume discusses the period 2003-2008 and observes that Sea ice thickness exhibits a small negative trend while area increases in the summer and fall balanced losses in thickness leading to small overall volume changes.
The web page Antarctica's ice loss on the rise discusses the three years from 2010 and observes the West Antarctic Ice Sheet is losing over 150 cubic kilometres of ice each year. This includes ice beyond the grounding lines which is floating on the sea.
The suggested web page Press Release: Arctic sea ice shatters previous low records; Antarctic sea ices edges to record high suggests that the Antarctic changes are due more to wind than warmth.
It is possible that the increased Antarctic ice extent could be due to wider distribution of thinner ice and could still represent a loss of sea ice volume.
Saturday 25 January 2014
Week 2 - End of Week Reflections
This week I have come to appreciate the complexity of the climate system with its many feedbacks both positive and negative. In particular, the influence of the Earth's orbit around the Sun.
The most difficult part was Section 2.6 on 400 parts per million. I'm still not entirely clear what forced the rise in carbon dioxide in the mid-Pliocene. Was it just the orbital changes driving up temperature? Clearly lots of different processes interacting ...
Not exactly further research but I did attend the second in the Adaptation to Climate Change Seminar Series organised by the Centre for Science and Policy. Although both the course and the seminar series are aimed at a general audience their focus is different. As the title suggests, the seminar series is more narrowly focused on adaptation. Thursday evening's seminar mentioned the U.S. Global Change Reseach Program which might be in interesting source of information.
A couple of interesting observations from the seminar: A temperature increase of between 1.75 C and 2.75 C by 2050 is predicted by all the climate models; and the rate of climate change will double over the next 20 years.
The first seminar had pointed out that even in the highly unlikely event that no more man made greenhouse gases were emitted the levels of the oceans will continue to rise for at least a thousand years.
The most difficult part was Section 2.6 on 400 parts per million. I'm still not entirely clear what forced the rise in carbon dioxide in the mid-Pliocene. Was it just the orbital changes driving up temperature? Clearly lots of different processes interacting ...
Not exactly further research but I did attend the second in the Adaptation to Climate Change Seminar Series organised by the Centre for Science and Policy. Although both the course and the seminar series are aimed at a general audience their focus is different. As the title suggests, the seminar series is more narrowly focused on adaptation. Thursday evening's seminar mentioned the U.S. Global Change Reseach Program which might be in interesting source of information.
A couple of interesting observations from the seminar: A temperature increase of between 1.75 C and 2.75 C by 2050 is predicted by all the climate models; and the rate of climate change will double over the next 20 years.
The first seminar had pointed out that even in the highly unlikely event that no more man made greenhouse gases were emitted the levels of the oceans will continue to rise for at least a thousand years.
Thursday 23 January 2014
Tuesday 21 January 2014
Week 2 Reflections
What are climate change records?
Climate change records come from many sources. David Parker's Youtube video describes many of them. One that surprised me was data collected from oil wells: "Depth profiles of temperature in oil-drilling boreholes can be used to
estimate the changes in air temperature over recent centuries".
Another interesting source of climate data is the Argo project, an array of around 3,000 profiling floats that provide observations
from the global ocean. These float measure temperature, pressure and salinity from the surface down to 2000 metres. When the float resurfaces it transmits its data to satellites which also determine its position.
How do volcanoes affect climate change?
The air around us contains all manner of small particles and liquid droplets. These are known as aerosols. The bulk of aerosols are from natural sources, some of which is ash from volcanic eruptions.
Volcanic eruptions can affect the climate in three ways: the ozone effect; the greenhouse effect; and the haze effect. Satellite data has confirmed that major vocanic eruptions, such as Mount Pinatubo, can cause short term ozone depletion in the atmosphere. Volcanic eruptions can enhance global warming by adding carbon dioxide to the atmosphere. The haze effect that results in global cooling is mainly caused by sulphur rich gases from the eruptions combining with water vapour in the stratosphere to create sulphuric acid droplets which absorb solar radiation and scatter it back to space.
How is today’s warming different from the past?
The main difference is that current climatic warming is occurring much more quickly than in the past. The Earth is predicted to warm by between 2 and 6 degrees Celsius in the next century which is at least 20 times faster than found in the past.
What is the role of isotopes in determining temperatures from the past?
Oxygen exists in two stable isotopes and the ratio of these found in calcium carbonate from the shells of creatures found in rock formations can be used to estimate the temperature of the ocean when the shells were created. The same effect can be observed in oxygen found in ice cores. More details can be found here.
How have trees been used to reconstruct different climate variables across the world?
Dendrochronology is the science that uses tree rings dated to their exact year of formation to analyse processes in the physical world. For example, a broad tree ring would indicate a year of good growth and a narrow one a less favourable year. This can be applied to the study of the present climate and to reconstruct past climates. More details can be found here.
How can ice cores provide a record of atmospheric composition?
Air bubbles trapped in ice cores can provide a record of past atmospheric composition. More details can be found here.
Sunday 19 January 2014
Week 1 Reflection
I was caught out by the question on greenhouse gases. Should have known that ozone was one of them.
The presentation using the blanket analogy rather than the greenhouse one was interesting.
Also interesting to compare the style of this MOOC with another I am studying on https://iversity.org/courses/public-privacy-cyber-security-and-human-rights.
On Thursday evening I went to the first of a series of six seminars http://www.csap.cam.ac.uk/events/Adaptation-to-climate-change-seminar-series/. It will be interesting to compare this with the course. The introductory seminar covered the history development of the science of climate change.
The presentation using the blanket analogy rather than the greenhouse one was interesting.
Also interesting to compare the style of this MOOC with another I am studying on https://iversity.org/courses/public-privacy-cyber-security-and-human-rights.
On Thursday evening I went to the first of a series of six seminars http://www.csap.cam.ac.uk/events/Adaptation-to-climate-change-seminar-series/. It will be interesting to compare this with the course. The introductory seminar covered the history development of the science of climate change.
Monday 13 January 2014
And so it begins ...
This is my blog to accompany the free course on 'Climate Change: challenges and solutions'.
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Pliocene Role in Assessing Future Climate Impacts "The middle part of the Pliocene epoch, approximately 3.3–3.0 million years ago [was] about 2–3 C warmer globally on average than today". It also states that "the mid-Pliocene was similar to today in terms of the positions of the continents and oceans and atmospheric carbon dioxide concentrations, but global warmth was distributed differently".
Although similar in many ways to today, the sea levels were 25 metres higher and there was less ice sheets and glaciers. The orbital movements were different, being dominated by obliquity rather than eccentricity. This resulted in higher temperatures warming high latitude oceans driving ice-albedo feedback. Maybe these changes had an impact on the flora and fauna causing less carbon to be transported from the atmosphere through the hydrosphere to be stored in the
lithosphere?