Climate Change

Wednesday, August 16, 2006

CLIMATE CURVE BALLS



I have taken this heading from a presentation Guy Midgley from the Climate Research Working Group at SANBI has given at the Fynbos Forum last week. Here is a short summary of his lecture. Or at least how I understood and interpreted it.

The reason why so much research is going into detecting and predicting climate change is ultimately to influence policy, behaviour and new technology on a world wide scale. That the climate is changing is difficult to dispute and is accepted by most people in the scientific community. Can we stop climate change? No, but we could possibly slow it down or change its course somewhat.

Adaptation is the only option and the doomsday scenarios that seem to be getting a lot of attention in the media lately have got a positive side to them. They are essentially unmitigated worst case scenarios and could be used to tactically galvanize mitigation responses. A fairly recent paper by Thomas et al. (2004) was widely quoted in newspapers. But as sensation is what sells, the media usually concentrates on the worst case scenarios… and omit the mitigated scenarios. According to Thomas et al. (2004) there could be an 11% extinction rate of global biodiversity by the year 2050 even if the climate only changes minimally (minimum climate change scenarios), but this could rise to a whopping 58% extinction rate of global biodiversity for the maximum climate change scenarios. (Although the media apparently focused on the 58% and elaborated on the how great such a loss would be, I find 11% also quite shocking!!!)

Guy Midgley focused on four factors that will have a major influence on the environment as the climate changes. These are climate extremes, fire, water and carbon dioxide. For climate extremes, it is not only the mean values that are changing, but also the number of extreme climate events. These extreme events could exceed the tolerance levels of many species, especially if these events become more frequent. Should the low extremes of temperature shift just slightly towards warmer temperatures, this could also have an adverse effect on some species as some seeds need that extra cold temperature as a cue to germinate.

Although the overall average temperature increase in the Western Cape over the past century was not much, the average minimum temperature has increased by two degrees Celsius! There are also definite changes in the precipitation trends of the Western Cape over the past 50 years. Although trends are difficult to analyze, there seems to be a definite increase in extreme rainfall events. Here it is vital to understand how important institutional memory is!

As conditions are becoming hotter and drier, fires will become more frequent. These fires are likely to become very large scale fires, burning to the ground huge areas at a time. Although natural habitats in the Western Cape are fire dependent, too frequent fires could have detrimental effects on the fynbos biome. Many plant species have a relatively long juvenile period and do not set seed before they have reached a certain age, which can be up to 10 years for some Proteaceae species. Thus too frequent burns can wipe out populations, especially if these fires cover large areas! Some climate scenarios are predicting a doubling or even tripling of fire risk days in the Western Cape by 2050. This means education is paramount in achieving minimal accidental ignitions. Having a ‘braai’ in or close to fire prone vegetation should not even be an option! (And places like Table Mountain should be declared smoke-free zones… )

Water is a scarce commodity in the Western Cape, although the majority of our population hasn’t caught on to this fact yet! Capetonians know all about water restrictions, but most seem to think it was just a temporary problem (and so does the municipality apparently, for why did they abolish the water restrictions after the first good rains???). Climate modelling for precipitation has only been done at a course scale up to now and fine scale modelling needs to be done as techniques improve. Present models predict less precipitation overall, but an increase in heavy downpours. The conundrum in Cape Town is however the fast expansion of the city… so even without climate change, we are going to run out of water.

There are already possible indicators that the water table is dropping. Some fynbos species occupy water micro-niches and these will probably be affected first. Some species occur according to water table depth and already some dye back of Proteaceae species has been noted in an otherwise healthy stands. Could this be an indicator of a drop in the water table? There has also been much talk of tapping into aquifers around Cape Town (I have heard of one in the Kogelberg Biosphere Reserve that has been earmarked for tapping…) to try and meet water demands of the growing city. (Again, I feel education is the starting point and not sourcing more water supplies… we could all do with using less water!)

The increase in carbon dioxide in our atmosphere is acting as a fertilizer to many plants. This however apparently is not true for Mediterranean-type shrubland vegetation… According to Dr. Midgley, fynbos species do not respond to the increase in carbon dioxide available, but invasive species could very well do. It has already been proven that Acacia karoo responds very favourably to an increase in carbon dioxide as more carbon is fixed in its roots that then become more robust. If this holds true for the alien Acacias we have here in the Western Cape, they might just have an unfair advantage!!

The theory behind climate change models is still incomplete and one therefore has to look at a range of scenarios. Careful monitoring right down to species level is necessary to try and detect early signs of adverse effects to a changing climate and then compare that to scenarios to see how accurate they are.

I found the presentation truly thought provoking and I hope that I have been able to portray the main points as they were intended by Dr. Midgley. (Take note that comments in brackets are my own and were not part of the presentation.)

Have we got the will and guts to change and to adapt our lifestyles to one that is more sustainable or are we going to wait until it is too late??




Reference:

Thomas CD, Cameron A, Green RE, Bakkenes M, Beaumont LJ, Collingham YC, Erasmus BFN, Ferreira de Siqueira M, Grainger A, Hannah L, Hughes L, Huntley B, van Jaarsveld AS, Midgley GF, Miles L, Ortega-Huerta MA, Townsend Peterson A, Phillips OL and Williams SE. 2004. Extinction risk from climate change. Nature 427:145-148.

Image credit: http://www.flickr.com/photos/twmlabs/29463820/


Karen Marais
BCB Hons NISL student
University of the Western Cape
Private Bag X17
Bellville

E-mail 2657211@uwc.ac.za

Web http://brit-journal.com/karen2006bcbnisl/


PLAGIARISM DECLARATION
1.I know that plagiarism is wrong. Plagiarism is to use another’s work and to pretend that it is one’s own.
2. I have used the CSE/CBE convention for citation and referencing. Each significant contribution to, and quotation in this project from the work, or works, of other people has been attributed, and has been cited and referenced.
3. This assignment is my own work.
4. I have not allowed, and will not allow anyone to copy my work with the intention of passing it off as his or her own work.

DO WE HAVE ENOUGH FRESHWATER?

The Western Cape or in particular Cape Town heavily depend on the annual winter rainfall to supply the province and city of their freshwater supply. The regular and consistent winter rainfall also regulates - as it has done it for the past 5 millions years, - this Mediterranean’s floral and faunal diversity. However with the steady rise of Carbon dioxide concentrations in the atmosphere, resulting in global warming, the whole rainfall pattern is expected to change. Climate computer modelling from the Hadley Centre predicts up to a 25% decrease in the annual rainfall in this province. With a population that are booming, Cape Town is fast becoming South Africa premier city after Jozi. The demand for water in this water scarce province will soar and to rub salt to our wounds, the climate will be inconsistent and heavy, prolonged droughts can be expected. The effect of a prolonged drought will be felt across this multiracial province from the poorest of the poor, to the boere and to the rich and famous. So what are the options?

Tony Robinson looks at the economics of water from the sea and ask whether desalination would be viable in South Africa, since it is quite successful in other countries. According to him, desalination is no the panacea to South Africa’s water shortages but it will provide a security of supply in times of need. The technology is available and several other countries and islands have employ this processes since most of these countries and islands don’t have the benefits of mountainous catchment areas, rivers and dams in place to get their freshwater. According Robinson (2006) about 80 % of all salt removing processes is happening in the Middle East, where water production is coupled with the power stations. This process in Middle East involves the usages of gas, oil and nuclear power to boil the sea water, where it condensed for drinking water. The Europeans, Americans and Aussies make use of reverse osmosis, which is the application of pressure to separate the salt and the water. This method or a simple version of this method have been in place since 1881 on the island of Malta and have supplied the people and its tourist booming industry (Robinson 2006).

So why don’t we implement such programmes? The reasons according Tim Robinson is that our dam water is cheap and it provide little motivation to save water. He say that only 10 % of this water are recycled while the other 90% that are treated just run into our oceans. Only 2% are used for drinking, cooking and washing of hands purposes while approximately 35% and 20% are used on baths, showers and garden respectively.
If the government can encourage its people and industries to save more than the current percentage, and not just when there is a water crisis, this province will not be surprised when human-induced climatic conditions take its toll.

Reference:Robinson T. 2006. Sweet water from the sea. Progress Magazine. p 34 -37


PLAGIARISM DECLARATION
1.I know that plagiarism is wrong. Plagiarism is to use another’s work and to pretend that it is one’s own.
2. I have used the CSE/CBE convention for citation and referencing. Each significant contribution to, and quotation in this project from the work, or works, of other people has been attributed, and has been cited and referenced.
3. This assignment is my own work.
4. I have not allowed, and will not allow anyone to copy my work with the intention of passing it off as his or her own work.

REVIEW: CAPTURING CARBON TO SLOW GLOBAL WARMING – Jamie dePolo

It started out as a far fetched scare, but now global warming has become a scientific reality. Greenhouse gases in the form of CO2, methane and nitrous oxide are the main gasses that act as a car’s window, permitting solar radiation which causes an increase in temperature. Unless the windows stay close, no heat can escape, but if the windows are lowered, heat can escape that refresh the car. The mentioned above process are a modified version of the real greenhouse – effect.

The Kyoto protocol was set up in 1997 with the intention to target greenhouse gas emissions of the developed countries. Due various economic reasons, Australia and the US did not ratify the protocol. Up till today these two countries haven’t agree to the protocol. However, in 2004 Russia approved and confirms their part in the whole global warming and greenhouse scenario. This means that the Kyoto protocol is in binding since February 2005. In the meanwhile, scientists and researchers have look for methods and management strategies that would both benefit farmers and the environment.

The two dominant greenhouse gases are carbon based: Carbon dioxide and Methane. One way of keeping carbon dioxide in the soil rather than in the atmosphere is through tillage management. No till makes soil more stable increasing water and nutrient capacity, resulting in better crop production but it doesn’t end there.
Another way to minimize Carbon concentration is by looking at wetlands.
According this article, wetlands cover about 3% of the Earth’s surface which provide services to humans and carbon sequestering is one of them. Peat lands are wetlands with a different taste. It contains layers of dead biomass that have accumulated over the decades and with as much of 50 % of Carbon stored within it. These peat lands hold approximately 30 % of soil carbon which invite managers to protect this already scarce ecosystem. Studies in Alaska, reveals that as the ice starts to melt, the plants species that are anti – decomposition perform much better and can thus extract more carbon dioxide from atmosphere. However as climate gets warmer the peat lands will get drier and will be more fire prone. The amount of CO2 released from peat lands after a fire is unknown and further studies are necessary to determine that.

To come back to the role of agriculture in carbon sequestering, it will provide a short term solution for the high levels of carbon based compounds until alternative fuel sources are available. Plants and crops use carbon dioxide during photosynthesis, but when leaves or other plant matter falls to the ground, it is either converted to CO2 or it will be part of the soil organic matter. Practises such as no tilling, mentioning earlier means that soil are not tilled each and every year, but there are time when the soil are left alone. This will allow carbon to stay longer in the soil and out of the atmosphere. There are also benefits that accompany the no tillage practises, which is mention earlier. Agriculture contributes 20 -40 % to the GHG emissions, thus tackling this problem will reduce CO2 to about 8 – 10% which are required by the Kyoto protocol.

Similar to that of peat lands, the question remain for how long will the soil hold unto the carbon and how easy will it be released when the soil are tilled. Carbon sequestering is not the solution to our problem but it will give us time, something that we don’t have!



PLAGIARISM DECLARATION
1.I know that plagiarism is wrong. Plagiarism is to use another’s work and to pretend that it is one’s own.
2. I have used the CSE/CBE convention for citation and referencing. Each significant contribution to, and quotation in this project from the work, or works, of other people has been attributed, and has been cited and referenced.
3. This assignment is my own work.
4. I have not allowed, and will not allow anyone to copy my work with the intention of passing it off as his or her own work.