Carbon is one of the main elements found all organic molecules including carbohydrate, protein and lipids.
Carbon is found in one of four 'pools':
Biosphere
Oceans
Atmosphere
Sediments
carbon is moved between these four pools by a variety of biological, geochemical or industrial processes.
Processes:
Photosynthesis by terrestrial plants and algae (freshwater and oceans) in which atmospheric (and dissolved ) carbon dioxide is removed and fixed as organic compounds such as carbohydrate, lipid and protein.
Respiration by all organisms in which they metabolise organic molecules releasing carbon dioxide.
Feeding, in which the carbon of organic molecules is move from one link in the food chain to another.
Fossilisation in which carbon as organic molecules becomes trapped in sediment as coal. gas and oil.
Combustion during the burning of fossil fuels and burning of biomass.
I do not provided a carbon cycle here in the hope that you will apply the above principles to any carbon cycle diagram that you find in a textbook or online. The following carbon cycles will provide to identify the processes and pools of carbon.
The trends in atmospheric gases are studied as indicators of potential climate change.
Major gases studied include carbon dioxide, methane and oxides of nitrogen are collectively called the greenhouse gases (5.2.3).
Atmospheric carbon dioxide has been monitored at Mauna loa atmospheric laboratory on Hawaii since 1958 (pdf). There are now other laboratories around the world which are adding to the database of carbon dioxide levels in the atmosphere. The data can be accessed at The Carbon Dioxide Information Centre, Department of Energy, USA by searching 'Trace Gas Measurements'.
Carbon dioxide is released unevenly around the world which is in part due to the distribution of vegetation. The collective data therefore allows us to see what happened after there is a mixing of the atmospheric carbon dioxide.
The analysis of carbon dioxide trends is complex and is affected by a number of factors and assumptions.
However the basic trend is an increase in atmospheric carbon dioxide levels.
Students can follow a more complex but very readable analysis on the Open mind blog.
Longer term estimates of global CO2levels have been determined by a variety of sources including the gases trapped in ancient ice cores.
Bubbles of atmospheric gases are trapped within the ice formed thousands of years ago. Taking cores of the ice and then analysing the gases allows the CO2levels to be determined.
The temperature can be determined from the same gas sample as the ratio of oxygen isotopes O16and O18 .
Conclusion:
There is a clear correlation between atmospheric CO2 and temperatures.
Correlation of course does not mean causation.
Note that the CO2levels today are higher than ever in the past.
The dashed blue line is an extrapolation of the curve.
Students should note:
Greenhouse effect is a natural process that creates moderate temperatures on earth to which life has adapted. The earth has relatively little carbon dioxide in its atmosphere compared to a planet like venus which has an atmosphere of CO2 x 200, 000 times greater and a surface temperature nearly twenty times higher than earth.
Enhanced greenhouse effect is the concerned that the activities of may be increasing the levels of carbon dioxide and other 'greenhouse gases' such as methane and oxides of nitrogen in the atmosphere. That this may lead to increased global temperatures and climate change.
a) Short wave solar radiation (light)
b) light penetrates the atmosphere and passes through the molecules of the atmosphere
c) Absorption by the ground and conversion to long wave infrared radiation (heat)
d)This warms the planet
e) Some infrared is lost to space as heat
f) Atmospheric gases particularly water vapour, carbon dioxide, methane and CFC's
g) Greenhouse gases absorb infra-red radiation and scatter this rather than letting it escape to space. In effect this traps the heat energy.
h) Some light reflects off the outer surface of the atmosphere and never enters
Note that if this 'greenhouse' effect did not exist the average global temperature would be -17 C.
The enhanced greenhouse effect.
Increase in carbon dioxide and other greenhouse gases (methane, oxides of nitrogen) will increase the particles(f) in the above diagram.
Therefore more infra-red will be absorbed, scattered and retained as heat.
The average global temperatures will rise. Some models suggest as much as 40C in the next 50 years.
An enhanced greenhouse effect is predicted to cause global climate changes. This is often referred to as global warming but whilst the average global temperatures may rise the local effects may vary widely.
Syllabus:
'If the effects of human-induced change would be large, perhaps catastrophic, those responsible for the change must prove that it will not do harm before proceeding.'
William Clifford in his 1879 essay "The Ethics of Belief", contains the famous principle: "it is wrong always, everywhere, and for anyone, to believe anything upon insufficient evidence."
In this context Clifford would have argued that its is wrong ( immoral) to believe in climate change or the causes of climate change until there is sufficient evidence to to support this view.
Cliffords argument is an extension of the 'Burden of proof' principle in which (in context) it is up to those who claim that there is climate change( due to human causes) to prove that this is the case. That there is no need to respond to request for action to reduce human impact until that case has been proven.
However the 'Precautionary principle' suggests that the obligation actually falls on those accused of causing climate change (or enhanced greenhouse effect) to show that their actions are not causing damage. If we wait until it is proven that humans are causing climate change it will be too late to reduce the impacts. Iis is better to respond now as a precaution even if in the long term it turns out that the case cannot be made.
The use of the precautionary principle in risk assessment is covered in this policy document form the UK Health and Safety Executive.
This wiki article is a good summary of the precautionary principle.
Modern Skepticism ( do not confuse with the ancient Greek version) has a number of tools that allow the critical examination of phenomena. These tools are often used in the natural sciences to examine the quality of evidence which is provided in support of a hypothesis. Such tool include:
Burden of Proof; in which the obligation is on those who make claims about the causes of phenomena to provide the evidence before other might change their understanding or behaviour.
Occams Razor; in which a phenomena is always explained with reference to the simplest possible explanation.
Sagans Balance; which is the principle that extraordinary claims require extraordinary evidence.
Authors such as William Clifford (more recently Jonathan Adler) argue that it is unethical to believe in a phenomena for which the evidence is poor.
The Precautionary principle reverses the argument of the 'Burden of Proof'. The precautionary principle argues that those responsible for an effect (global warning, climate change, enhanced greenhouse effect) have the obligation to show that what they are doing has causes no harm.
In context of the enhanced greenhouse effect then:
Skeptic approach: The 'burden of proof' lies with those claiming that harm is caused by those responsible for the enhanced greenhouse effect to provide evidence that this is in fact the case. In other words, the environmentalist need to provide conclusive evidence that the actions of the 'polluters' are causing harm to the environment.
Precautionary Principle: Those allegedly responsible for causing the effects of the enhanced greenhouse effect are required to demonstrate that their action do not cause harm. This responsibility would then fall on a wide spectrum or Nation Government, Industries, Communities and individuals to demonstrate that their actions cause no harm. This includes the actions of every individual including you, the reader!
Climate is a complex phenomena with many emergent properties often based on time frames beyond the human experience. This make the exact predictions of location and timing it difficult. It is however possible to hypothesis about the general effects.
increased frequency and intensity of droughts;
flooding as a result of higher rainfalls, increased snowmelts, and rising sea levels; This interactive site allows maps you to determine the rise in sea level and the effects this will have on coastlines. (Brilliant !).
declines in food production;
increased disease; infectious pathogens ar generally reduced by cold temperatures (winter). warmer temperature will allow pathogens to survive better and indeed for diseases to extend their distribution. Current evidence suggest that both malaria and dengue fever are currently extending their distribution.
more extreme weather; and
External Links to websites of climate change.
External Links to reducing your carbon foot print
Climatecrisis: calculate your carbon footprint.
Energy efficient appliances find out about reducing your energy demands in the house hold.
Simply insulate further information on positive responses to reducing your carbon foot print.
Cutting energy costs 10 ways to reduce your energy costs.
Energy Audit a self help guide to performing an energy audit on your home.
Standby energy leakage on those appliances that 'leak' power when left to standy-by.
Alternative energy sources alternative power sources to fossil fuels.
maximise fuel efficiency from your car making the most of the fuel in your driving.
Hybridcars how hybrids work and a comparison with other methods.
Alternative car fuels Biodiesel, ethanol and more to put in your tank.
Fuel cell vehicles Hydrogen power fuel cells
Vulnerability and Adaptation to Climate Change in Developing Countries
This excellent article by Chris Ward written (30th July 2007) for the World Resources Institute, considers that fact that some people are now working towards their own methods of adapting to climate change rather than how they will reduce climate change:
'Current scientific evidence shows, however, that some human-induced climate change is now inevitable and is in fact already occurring. The question of which regions and groups are most vulnerable to this predicted climate flux and how they might adapt to it has thus become an important area of research, funding, and policymaking'.
The full article is an excellent read and provides stimulus material for debate and discussion for our role as responsible global citizens
The arctic is an ecosystem by Bill heal is a web resources on human-environmental relationship in the arctic and an excellent introduction for IB Biology students, read it all! This resource is part of the wider, The Stefansson Arctic Institute.
Bill writes, 'Predicting changes over the next 50-100 years is difficult! It is not only the changes in the balance of production and decomposition within the system that have to be considered. It is also the rate of spread of vegetation following the gradual changes in climate. This is where the computer models come into play. The most recent model summarises the climatic factors driving change, and the responses of plant growth and soil organic matter. It is expected that the mean annual temperature of the region will rise by about 4°C this century, more in the High Arctic, less in the subArctic and Boreal forest. Snow and rain will change much less, probably increasing by only a few centimetres each decade. Based on these assumptions, the model is then run from 1850 to 2100, covering the circumpolar region from 50o Northwards.
The article continues 'It predicts that:
Coniferous forest will expand at the expense of tundra.
The present tundra area will be halved by 2100.
The increased growth of forest will exceed increased decomposition so that the region will continue to be a carbon 'sink' throughout this Century. '.
These three changes highlighted in Bill Heal's article clearly spell huge changes for the arctic ecosystems. Please read all the chapters in his article for a full appreciation of the arctic ecosystem and how climate change has and will effect on this most beautiful of places.
5.2.1 Carbon cycle
5.2.2 Historical records of atmospheric gases.
5.2.3 Atmospheric gases and the enhanced greenhouse effect.
5.2.4 The precautionary principle.
5.2.5. The precautionary principle and the greenhouse effect.
5.2.6 Greenhouse effect and the arctic ecosystem.
