Oh blimey, when they said an online course I just thought it would be all watch a video here, read an article there... I didn't expect there to be social media interaction and the need for a blog. However, I am not one to shy things off likely especially when social media is involved. I am what you call a social media whore, which my girlfriend mentions on a daily basis, so I am happy to oblige.
Right then here I go with the blog. This is collection of bits and bobs I've learnt from Week 1...
Introduction
Greenhouse effect and the Earths little cuddle blanket
The greenhouse effect is not a good metaphor but everyone seems to be using it!Effectively, the suns rays come in as long waves hit the earth and reflect as short waves (infrared heat). However, the waves going out don't just disappear into space, they get absorbed by gas in the atmosphere, which are called green house gases (GHG)
The reason that the green house analogy isn't suitable is because the gases really work as a blanket around the earth, keeping the warmth from the person (earth) escaping but also returning the heat back to the person (earth) to keep them warm.
The heat that gets reflected back from the gases is called Albedo:
Some gases in the atmosphere are long-lived and remain semi-permanantly in the atmosphere and they do not respond physically or chemically to changes of temperature so these are 'forcing' clime change. Other gases such as water vapour do change and tare called feedbacks.
The gases which contribute to the greenhouse effect are:
- Water Vapour - most abundant, increases as temp of Earth warms which increases clouds and precipitation
- Carbon Dioxide (CO2) - minor components of the atmosphere but most important long-lived gas forcing climate change.
- Methane - more active then CO2 but less abundant
- Nitros Oxide - one of the most powerful GHG
- Chlorofluorocarbons (CFC's) - have the ability to destroy the ozone layer
Weather and Climate
Some people get a little confused about which is which, so here is a brief description of each:
Weather
Elements which we see daily such as temperature, rainfall, wind, snow and which change on a daily basis.
The weather takes into account the temperature, precipitation, humidity and atmospheric pressure of the part of atmosphere (air) closest to the surface of the earth.
The weather is constantly changing as temperature and humidity change in the atmosphere. Landmasses, such as the British Isles, experience constantly changing weather conditions.
Climate
Climate refers to what is expected to happen in the atmosphere rather than the actual conditions. It is possible for the weather to be different from that suggested by the climate.
Feedbacks and cycles
There are 5 different elements of the climate system:- Atmosphere
- Hydrosphere
- Biosphere
- Cryosphere
- Lithosphere
Feedbacks operate in the climate system which are a closed loop of cause and effect.
There are 3 keys feedbacks systems effecting climate change:
Water vapour - temperature rise, increase evaporation which increases water vapour which increases temperature and on and on. This is a positive feedback.
Ice albedo - Suns rays come down and get reflected by the ice and absorbed by the ocean, as the ocean absorbs the heat the ice melts which increases the ocean surface area and increases the temperature of the earth which means more ice is melting. Negative feedback.
Radiation - All objects give off radiation but the warmer the object the higher the radiation and the more radiation given off in heat energy the cooler it becomes, this happens in the use of coal as a fuel. Plank feedback as described by the guy who discovered it. Negative feedback.
The climate system self-regualtes through negative and positive feedback systems.
Negative feedback — this is an impact which offsets the prevailing change in climate. Under global warming, this would create a cooling effect, balancing out the changes. If the climate was getting colder, it would create a heating effect.
Positive feedback — this is an impact which increases the change in the climate. It would add to global warming by creating further heating or, if our climate was cooling, would cool the climate further.
IPCC (Intergovernmental Panel on Climate Change) - this is the leading inter nation body for assessing climate change. It was established in 1988 by the United Nations Environment Programme (UNEP) and the World Meterogical Organisation (WMO). Thousands of scientists around the world contribute on a voluntary basis.
My reflections on the first week:
What are the most important themes you have learned this week?
The science behind climate change and the various systems involved.
What aspect of this week did you find difficult?
Feedbacks and understanding positive and negative feedbacks
What did you find most interesting? And why?
Climates and weather systems and everyones descriptions of then on the course.
Was there something that you learned this week that prompted you to do your own research?
Only to look up what things actually mean such as scientific words I had never heard of such as albedo, lithosphere and what climate and weather actually was.
Are there any web sites or other online resource that you found particularly useful in furthering your knowledge and understanding?
Nasa website: climate.nasa.gov/causes/
Earth and Space research: www.esr.org
Met Office www.metoffice.gov.uk
http://www.bbc.co.uk/schools/gcsebitesize/geography/weather_climate/climate_rev1.shtml
Phew. Week one done. Over and out...
Hi Charly, I am on the course too! Like you, I found feddback loops tricky to get my head around, but hopefully the more the information is used, the more it sticks in our brains! Feel free to have a look at my post - not sure it is as comprehensive as yours though!
ReplyDeletethanks Lou. I'll check out your post. thanks for the feedback :)
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