icebergs

About 8 years ago I took a trip to Newfoundland in June and got to see the icebergs.  Whether they were ice bergs from sea ice or land ice, I don't know.  At the time, I thought they were beautiful and was so excited to be in Newfoundland to see them.  Now, knowing what I know, they cause me anxiety - are they from land the ice of greenland that is being lost at a rate of 286 billion tons per year or from an ice shelf that is still attached by land or from sea ice. And again, from earlier in the course, less ice cover of the land and the oceans, means less ability to reflect back the radiation from the sun and more warming.  

The discussion question with regards to icebergs (or calving) in this section of the course was: How might processes like ocean and atmospheric warming cause mass loss from calving to increase? 

So first let's define calving.  This is where pieces of ice break away from a glacier that ends in a body of water (ie a land glacier extending into the ocean and then breaking away from its base). 

So how will ocean warming contribute.  Ocean warming can melt the underside of the glacier ice shelf (the part of the glacier now on the ocean but still connected to land glacier) weakening it and contributing to calving.  Atmospheric warming can lead to less snow fall and less ability of the normal summer time ice melt to refreeze back to the ice mass.  So with both loss of snow and less ice melt refreezing, there is less accumulation of mass and the glacier starts to spread out more to the edges of the land where they meet the warming oceans.  Atmospheric warming will also allow the lakes that form on the glacier itself more time to absorb more radiation (rather than reflect it back) which further warms them.  When they drain abruptly transferring heat to the interior of the ice sheet, the ice sheet can flow more rapidly to the edges (again meeting the warming oceans and leading to more calving.   

Reflections at the end of week 2

First reflection - it is taking me a long time to get through this course and unfortunately I will likely not finish it before it expires.  The reason - I always considered myself pretty "smart" in science when I was in school but I continue to struggle with the science as it relates to climate change. This is humbling but also makes me recognize how complex the science is and it seems to me that when there is topic that not only makes people uncomfortable talking about but is also really hard to understand, it is easier to just deny, distract or hope for the best without actually taking action. 

Second reflection - A sense of hopelessness has really settled in on me.  I really resonated with some of the thoughts expressed by the blogger of Above the Waffle who is also taking this course and who has a really well laid out and interesting blog in terms of what we are trying to "save" because it is us humans that have caused such horrible destruction so are we even worth saving (ie the planet and whatever life forms manage to survive the next extinction are probably better off without us).

I could go on but then I would likely be procrastinating the discussion questions for the end of week 2.  So here goes:

How does the climate vary naturally over millennial time scales?
Many factors have led to the natural variation of our climate over the last 4.5 billion years (ie the beginning of the solar system).  The intensity of the sun (burning brighter as time went on) could be considered one factor although the heat intensity of the sun doesn't seem to be as much as a factor as the gases (mainly carbon dioxide and water vapour) in the atmosphere that trapped the heat and radiated it back to earth to keep the surface warmer than if it was just relying on the sun's intensity alone (ie the blanket around the earth).Carbon dioxide seems to be the biggest factor.  Not only was it operating as part of the blanket effect, it would often combine with rain (the water vapour in the atmosphere) to form carbonic acid.  The acid would dissolve the rocks (a process called chemical weathering) releasing various ions (calcium, magnesium, sodium, potassium and carbonate).  The rivers would carry the ions to the ocean and shell building organisms would form calcium carbonate using the ions.  When the organisms died, they would sink to the bottom of the ocean and all the shells and sediment would combine to form more rocks.  So here we have a negative feedback loop which was a way the earth was self regulating its temperature "naturally".  Increased temperature would cause more evaporation of water reacting with more carbon dioxide and essentially removing more of it from the atmosphere to be stored in the lithosphere (thus reducing the blanket effect).The cooling of the earth with the chemical weathering and the creation of continents also lead to snow ball earth (the freezing of the earth 2.2 billion and 700 million years ago).  Here more ice cover continued to reflect back the sun's radiation so that eventually ice cover closed up from the poles to the equator.  However carbon dioxide again played a key role when over time, large amounts were released by volcano eruptions and since there was reduced water vapour (? was there any?) in the earth's atmosphere to combine with it, the carbon dioxide levels kept building up and thereby increasing the temperature until melting started to occur (and with further melting, more heat could be absorbed by the explored dark water rather than reflected back by the ice cover).

Can contemporary climate change be explained by natural variations?
There may be a few natural variations that has slowed the effect briefly but overall, the increased ability to have accurate data collection both for current and past indicators such as global temperature and ocean temperature and linking it to the graphs of carbon dioxide in the atmosphere and what we know is causing increased levels (burning of fossil fuels) that we have been producing as humans  shows that contemporary climate change is human caused.

What is the evidence for climate change?
I am basically using the NASA site which lay out 8 key facts that are concise and to the point:  Average temperature of earth increasing, average temperature of oceans increasing, shrinking ice cover, glacial retreat, decreased snow cover, sea level rise, artic ice decrease, extreme weather events and ocean acidification.  Again linking the highly advanced ways this data can be collected shows that the climate is changing and changing more rapidly then it ever has before

Extreme weather events in Thunder Bay, Ontario, Canada

• What extreme weather events impact where you live?

Although I didn't live in Thunder Bay at the time, in 2012, 120 mm of rain fell over 2 days in May (including 71 mm in less than 6 hours). This caused road wash outs, power outages, severe damage to hundreds of homes and businesses, issues at the water treatment plant and erosion to the city's landfill site.

Climate change is anticipated to bring an increase in average temperatures, shorter winters, rapid spring snow melts (increasing the risk of flooding) and more severe weather events (including freezing rain storms and tornadoes) to Thunder Bay in the future.

• Have you noticed any change in weather patterns with climate change?

I have noticed this especially in the middle of winter (December - February) where we often will have days of rain (rather than snow) which never occurred while I as growing up.

• Can we attribute extreme weather events to ‘climate change’?
• Scientists at the University of Minnesota (whose state also shares having one of the Great Lakes, Lake Superior on their shores), report that the changes to Lake Superior (increased surface temperature in summer, decrease ice cover, increased wind speeds) will lead to more frequent and intense storms. (http://www.seagrant.umn.edu/climate/superior)

carbon dioxide and 400 parts per million

• What could explain the changes in carbon dioxide concentration over millennial time scales?

We are now at 400 parts per million of carbon dioxide in the earth's atmosphere.  This is staggering given that for 400 000  it seemed that carbon dioxide was just following a fairly up and down pattern between 180 ppm and 300 ppm.

The reasons for the fluctuation are still a little over my head.  First you have the ways in which the earth has been circling the sun (eliptical or circular), tilting towards or away from the sun and "wobbling" on its access which from reading some of the comments from the other participants of the course, affected solar radiation coming in, warming the planet and then whether carbon dioxide could be released from the oceans).  Then there is volcanic activity also releasing huge amounts into the atmosphere at different times throughout history (which then may have acted like a cooling agent preventing solar radiation from getting in and changing the course of carbon dioxide being stored rather than released from the oceans.

• What could explain the changes in carbon dioxide concentration over recent time scales?

Understanding the science behind the fluctuations over the last 400 000 years is important as it seems it would allow scientists to look at all the complex factors and determine the main causes of the earth's rising temperature.  And since that cause is clearly increased green house gas concentrations with carbon dioxide increasing from 280 ppm to 412 ppm in the last 150 years (according to NASA's global climate change site), we, as humans have to take responsibility in recognizing the burning of oil and gas as the main cause and commit to ways stop our reliance on it.

Climate Science - End of Week 1

Wow this course is hard.  My 42 year old brain is not only trying to read and understand the information but then to explain the information (even if it is just to my blog).  This is something I haven't had to do a in over 15 years (when I finished my last degree).  I can usually correctly answer the multiple choice questions but the following more open ended questions, are challenging.  Which probably means I have a ways to go to be able to explain it to someone else in a way that makes sense to them. 

What are the key scientific principles that explain climate change including the greenhouse (blanket) effect?

- the earth's atmosphere has important  "Greenhouse gases" that act like a blanket around the earth allowing sunlight (short wave radiation) in.  This radiation can pass through the gasses and then be absorbed by the the earth's surface and the living things on it but it can also be reflected back towards space.   The Green house gases can now absorb/trap this reflected back long wave radiation and then re-emit it back to the earth keeping the earth's surface warm (and liveable).

- the Greenhouse gases that act like this blanket are water vapour, carbon dioxide, methane, nitrous oxide and ozone

- Human activity has caused changes (increases) in the concentrations of these gases which means more radiation is being reasborbed and re-emitted back to the earth surface and warming the temperature.

What are the key feedback mechanisms that help to explain why our climate is able to “self-regulate"?

This is definitely a question I am not sure I understand so not sure how to provide the "correct" response. 

The key feedback mechanisms seem to refer mostly feedback loops as they relate to warming.    So activities that are ampliflying or increasing the warming process would be called positive feedback mechanisms (for example the Albedo feedback where warming of the oceans means the melting of more sea ice which means less ability of the sea ice to reflect back solar radiation which leads to more warming of the earth's surface and the oceans).  The course also referred to water vapour feedback as a positive feedback where increased warming leads to increased evaporation which leads to more water vapour in the atmosphere that traps reflected radiation and sends it back to the earth's surface. 

However, The NASA Earth System science site also refers to increased evaporation as a negative feedback system where increased evaporation increases cloud cover which can reflect back sunlight before it enters into the atmosphere and therefore preventing it from coming to the earth's surface. 

I believe the self regulation component (and important negative feedback mechanism) described in both the course and the NASA site is radiation feedback were the Stefan Boltmann's law states that as the earth's temperature warms, it will increase its emission of infrared radiation back into space allowing the Earth to experience a slight cooling effect. 

How can our climate be conceptualized as a system containing a series of components that interact with one another?

The earth is a system of interacting parts.  These parts include the atmosphere (the gases encompassing the earth), the hydrosphere (the oceans, rivers and lakes), the cryosphere (glaciers, sea ice and ice fields), the biosphere (plants, animals, insects, soils) and the lithosphere (the earth's crust).  An example of the interaction of the systems is sunlight radiation along with carbon dioxide and water vapour already present in the atmosphere being used by plants in the biosphere to photosynthesize and release oxygen back into the atmosphere.  Because parts are so interconnected, the feedback mechanisms are really complex.

Greenhouse gas -- discussion on methane

I have chosen to talk about methane which is a "Greenhouse gas" that occurs naturally in the atmosphere along with carbon dioxide and nitrous oxide.  As discussed, these greenhouse gases absorbing and radiating heat back to earth acting like a blanket.  Without them the earth would have been too cold for life to exist.  Unfortunately with human activity, we are increasing the concentration of all of these gases so they are radiating more and more heat back to the earth's surface that is leading to a warming of a planet.

According to Global Methane Initiative (globalmethane.org), the human contributions to methane production are:

1. production of coal, oil and natural gas
2. municipal solid waste decomposing in landfills
3. waste water treatment facilities
4. domestic animal waste management systems
5. rice production

The Government of Canada's climate change site indicates that although methane will only last 12 years in the atmosphere after being emitted it can trap 70 times more heat in a 20 year period than carbon dioxide.  According to the Environmental Protection Agency in the US, 50-65% of methane emissions are due to human activities. Therefore methane plays a huge role in the greenhouse gas "blanket effect".

Not only will methane emissions contribute to warming of the planet but warming of the planet and the thawing of permafrost will release further deposits of what was frozen methane or what NASA describes as the rapid release of methane. 

Climate and weather

Canadians love to talk about weather.  "Wow it is cold out". "Geez we have had a lot of snow this year".  "It is way too hot - we need more rain".  So in discussing temperature, precipitation and wind, we are discussing weather and how it is being experienced right now.

I feel our observations are true as we know them to be but if we want to discuss climate - how the average weather patterns are changing in a specific region year to year over a longer term period, then we can't rely on our memories alone especially when the majority of us spend most of our days indoors in our thermostat controlled homes, schools, stores and office building and drive in our air conditioned or heated cars to go to and from places.  This is where we need the data.

Unfortunately, it is often challenging to wrap our heads around the data of climate because it is longer term and much larger scale then our daily routines/daily life allows us to notice especially if we haven't experienced a severe weather experience to really have it impact our lives.