Water and Carbon cycle

• When analysing markets, a range of assumptions are made about the rationality of economic agents involved in the transactions
• The Wealth of Nations was written

  1776
• Rational


  (in classical economic theory) economic agents are able to consider the outcome of their choices and recognise the net benefits of each one
• Rational agents will select the choice which presents the highest benefits
• Producers act rationally by


  Selling goods/services in a way that maximises their profits
• Workers act rationally by


  Balancing welfare at work with consideration of both pay and benefits
• Governments act rationally by


  Placing the interests of the people they serve first in order to maximise their welfare
• Rationality in classical economic theory is a flawed assumption as people usually don't act rationally
• A firm increases advertising

  Demand curve shifts right
• Demand curve shifting right

  Increases the equilibrium price and quantity
• Marginal utility


  The additional utility (satisfaction) gained from the consumption of an additional product
• If you add up marginal utility for each unit you get total utility
• e calendar year and then a per of potentially deficit um certainly utilization into deficit in the summer months so thinking about the balance uh within the drainage basin and the idea of water balance that then affects um some of our human activities is important with this water cycle um topic
• oh Katherine back to the carbon cycle I believe absolutely time to look at a bit of carbon and thank you ever so much for that Alice cuz that is um a area I think sometimes it's such a tiny little bit of specification it's easy to overlook looking at the water balance but it is something that if you understand it it can help you understand a lot of other aspects of the water cycle so that was absolutely brilliant so look at that particularly the diagram and the carbon cycle can also be seen as a system and we've got the carbon cycle uh with the carbon moving between the lithosphere the biosphere cryosphere oh I put biosphere twice in here so um that should be hydrosphere and atmosphere um and what we're looking at um when oh no right I'm getting myself confused now which one I got missing um but a global scale we're looking at the largest store of carbon being the lithosphere that is a massive amount of carbon in the um in the Rocks basically that are around us
• now one of again the Nitty Gritty little areas of the specification which students sometimes can Overlook is the fact that you're expected to know about the carbon cycle at different scales this could be at the plant scale so just looking at one plant it could be looking at the seer scale so looking at staging the development of a particular ecosystem it could be at the Continental scale and when we're thinking about Continental scale we um you know we're thinking about those large areas which feeds into this idea of looking at the carbon cycle globally
• so we've got here first of all we have got um the question which of these happens when a tree removes carbon from the atmosphere
• so still thinking about that plant scale so when we've got a tree um and soil microbes returning carbon to the atmosphere which one of these are we talking about now
• what percent of wood in general roughly is carbon
• if we have got a wfire um what is it doing to release carbon which of these releases carbon during a wildfire
• when the leaf litter rots so we're going to have trees are going to be dropping their leaves and branches and things like that and that's going to be rotting and which of these processes is going to be releasing carbon at this point
• what is the definition of a sear
• what is achieved when a SE reaches environmental equilibrium
• what scale includes the whole of the fast and slow carbon Cycles
• fossil fuels coal oil and gas are by far the largest contributor to global climate change change as in their burning accounted for over accounting for sorry 75% of global greenhouse gas emissions and nearly 90% of all carbon dioxide emissions
• volcanic activity returns carbon to the atmosphere
• volcanic activity returns carbon to the atmosphere via processes such as outgassing which is what people had during eruptions and weathering of lava flows which contain silicates
• worldwide uh volcanoes are emitting something like 130 to 100 380 sorry millions of tons of carbon per year whereas human activities lead to emissions that are something like 80 times that amount
• the student argument here says that negative feedback will mean tropical rainforests can restore equilibrium as more carbon in the atmosphere will lead to trees growing rapidly and sequestering more carbon
• this will not necessarily work as trees absorb more carbon and grow rapidly this could mean that they life cycle is speeded up and they die sooner and then release the carbon that's stored
• and they die sooner and then release the carbon that's stored
• when we're answering 20 Mark questions it is really good practice to be thinking about when you write something um is there another way to look at it is there an argument against it can you think about the significance
• maybe if we're saying you know um negative feedback is going to mean that we're not going to have such a issue in the future with the carbon in the atmosphere um you need to have this thinking about however maybe it won't work maybe there are other issues that are involved
• so really really good to be able to think about that um if you didn't know about that the world will not end
• some people are saying oh I've never leared about that but um you know don't worry because you are going to control in your 20 Mark answers what you're writing and you have control over your evaluation of your points as well
• that is why some of you been saying 20 Mark answers are the worst but actually in some ways they can be the best because as long as you make sure you answer the question you do have more freedom in those answers to be able to use the information that you know so that you can feel more confident and you can build up a really really good answer you can do this
• the second claxon would sound at this point to remind us that we have a second case study we need to know about for this water and carbon cycle topic and that's a river catchment at a local scale
• some of you will have studied a river that's close to you or perhaps where your school is um other people will have studied a sort of classic example so some people might have studied the upper catchment of the river X perhaps in the southwest of England um but you're going to write about the case study that you know about
• we also need to write things down in a logical order
• Chains of analysis or chains of reasoning

  1. Rearrange sentences to form a chain of analysis

  2. Need to know about the impact of precipitation and the implications of precipitation in the catchment and how that changes over time

  3. Relate to water supply or flooding
• precipitation affects stores and transfers in river catchments at a local scale in several ways