SOME CLARIFICATIONS ABOUT CLIMATE CHANGE:
Recently I have received some questions from my teen daughter about climate change and what it actually means. I realized, many of us don’t really pay attention because we assume, this will happen sometime in the far future.
However, even within this year, here in Netherlands we have already experienced some interesting variations of weather patterns. Summer weather was in April this year, and currently when it is supposed to be summer, we have spring weather.
Therefore, I feel that as an expert in development and as an environmentalist, it is necessary to clarify the issue of climate change for our own sake.
Climate change refers to the change in the statistical distribution of weather patterns over long periods of time (from decades to millions of years). The change may be in terms of weather conditions or change in the distribution of weather events. Eg. extreme weather or non occurrence of previous weather events. Changes may be for specific regions or globally , there are different processes that cause climate change: natural causes eg. Ocean currents, planetary movements, unnatural causes by human activities.
The atmosphere of earth planet consists of two layers namely the troposphere and the stratosphere.
The lowest layer (zone for weather and climate) is the troposphere. The higher layer –stratosphere- is the zone whereby there is high radiation energy from the sun, which reacts with oxygen forming Ozone – an important gas that forms a protection layer which shields living things from most of the sun’s harmful ultra violet rays that can also cause skin cancer.
To understand some of the mechanism of the climate system, we look at the positive and negative feedbacks.
As the sunlight hits the planet, some of the energy is reflected back. The amount of reflection (albedo) depends on the features of the earth surface. Forests and oceans have low albedos, while i.e snow covered surfaces have high albedos.
The ocean capacity to absorb and store the energy, postpones the fast increasing global warming. ‘Feedbacks can occur in a system when the interactions between it’s component processes respond to a change of conditions. The interaction can either augment the original change (positive feedback) or reduce it (negative feedback)’
Positive feedback eg.
Greenhouse gasses i.e (methane, carbon dioxide, nitrous oxide, ozone) emissions to the atmosphere causing an increase of global temperature leading to extreme weather changes i.e drought, damaging vegetation and reducing forest cover (absorbs CO2), adds to global warming.
Negative feedback eg.
Industrial pollution increasing sulphate aerosols (a collection of tiny liquid or solid articles dispersed in a gas, such as water droplets or dust in the atmosphere - inside or outside clouds) in the atmosphere, will have a cooling effect to the atmosphere.
Feedbacks lead to cumulative climate change eg. Oceans absorbing heat, leads to rise of sea level due to thermal expansion, the heat continues to warm the waters at deeper levels spreading wider distances i.e Artic, melting ice caps adds to the rising sea level causing multiple impacts i.e floods, death of humans, damaging heat sensitive biodiversity eg. Corals, economic loss.
Increased temperatures also leads to increased evaporation affecting the climate patterns, eg. Extreme precipitation and/or extreme droughts affecting different individual regions in different ways. Some of the impacts may have a high probability of occurring but with low hazards, and vice versa, causing changes on social variables i.e some crops/animals may not be able to survive in maximum temperatures and this will have an impact throughout the food chain.
Climate models have been used by scientists from 1979 to calculate the operational climate system while estimating the possible future climates.
However, climate science lacks the accurate recordings of past millenniums to compare with modern occurring changes thus it is difficult to know if the changes observed are a natural trend occurring over long periods of time or specific for post-industrial era.
Climate science uses sample measures eg. Rainfall measurements: ‘..even with 5 gauges, the total area over which the rain is sampled is less than one square metre’. The measurements might also be affected by wind speed/direction and/or presence of obstructions eg. Buildings.
The various stages of climate models include developing scenarios of future world population including the number, technology used, economic activities, energy uses etc. Then making projections i.e how much pollution will be caused by the population, calculate the concentration in the atmosphere, then calculating how this will influence the climate system in terms of weather elements e.g temperature, precipitation and other components including the state of the ocean, ice and vegetation cover. Lastly, climate models analyse likely impacts based on the model state of the climate system predictions.
(unfortunatelly scientific models couldn't be downloaded)
As observed, the uncertainty of climate science is based firstly on the limitation of sample data, methods of obtaining data and different interpretations made by scientists. Secondly, if even one condition within a scientific model changes eg. Energy used, positive and preventive checks and/or government policies promoting environmental sustainability, the projections made by a particular scientific model become invalid.
This is why recent projections for global temperature rise by climate models show a wide range of temperature (between 1.4 °C – 5.8 °C) over the period of 1990 to 2100.
More information can be found in the book ‘Changing environments’, Edited by Dick Morris, Joanna Freeland, Steve Hinchliffe and Sandy Smith
Showing posts with label Challenges on development. Show all posts
Showing posts with label Challenges on development. Show all posts
Thursday, September 1, 2011
Thursday, October 1, 2009
Customers unhappy with LUKU
By Gadiosa Lamtey
28th September 2009
Many incur `unrecoverable loss` as network collapses again
Pre-paid meters (Luku).
The Tanzania Electric Supply Company (Tanesco) pre-paid meters (Luku) network collapsed over the weekend, the third time this year alone.
The failure partly frustrated business and domestic life, a survey by ‘The Guardian’ has established.
Most vending stations were down for the most hours of Saturday and yesterday. Tanesco authorities have blamed the failure to hitches on the Tanzania Telecommunications Company Ltd (TTCL)’s network.
According to Tanesco, the TTCL is responsible for managing operations of the systems of its Luku vending stations.
Interviewed, some customers who endured the brunt of living in darkness for about 24 hours talked of unrecoverable losses they incurred as a result of the Luku system failure.
A Luku customer from Mwananyamala, Nuru Mhina, said on Saturday she slept in darkness and was forced to throw away some foodstuffs which were stored in the fridge.
“The food rot in my fridge because Tanesco failed to supply us power through its vending stations,” she complained.
She said the problem of network failure was now becoming common with increased occurrence.
Nuru was also very much concerned over failure of the power utility company to notify the customers on the failure.
Complaining about delays, she said: “You may go to a vending centre at 10 am and get caught in a long queue until say 12. Sometimes, we are being forced to postpone other activities just to buy power,” she said.
Another customer at Oilcom Science area Hamisi Songoro who spoke to ‘The Guardian’ while standing in queue waiting for his turn to get the service proposed that it would be better for Tanesco to return to the previous system of post-paying because the Luku system was becoming ‘cumbersome.’
“It’s very bad that the system is becoming inefficient…Tanesco should tell us what all this means and for how long this problem will continue,” a frustrated Songoro said.
Songoro said while it was true that some customers purchased power through mobile phone special services, the system covered only those with digital meters.
“They should bear in mind that a large section of customers are living in houses installed with old Luku meters which operates by using punching cards,” he said.
Tanesco Public Relations Manager Badra Masoud admitted there was problem of network on Saturday which was caused by the TTCL communication network failure.
Badra said such failures were ‘normal’ and wherever they happen customers shouldn’t worry or panic.
She said Tanesco vending stations were open 24 hours to ensure people get the service without problems or delays.
‘The Guardian’ survey established that the system went off around 2pm on Saturday until at around noon yesterday whereby customers around the City were forced to return back home without power thus incurring losses in their business.
Among the Luku centres visited include Mwananyamala Kwa Manjunju, Oilcom at Science area, BP Kijiweni at Sinza, Mwanamboka at Sinza and Komakoma at Mwananyamala.
The system failed at least twice this year alone apart from the weekend’s incident. The previous failures were attributed to attack by an unknown virus and apparent failure of the computer system.
Last September, the Luku network collapsed abruptly due to a technical fault in its main computer system controlling the pre-paid services.
Luku vending machines first came into use in Tanzania in 1995, with most of them installed in Dar es Salaam. Besides Dar es Salaam, Luku metres are in use in Arusha, Dodoma, Mara, Mwanza and Shinyanga regions and several other major urban centres.
SOURCE: THE GUARDIAN
28th September 2009
Many incur `unrecoverable loss` as network collapses again
Pre-paid meters (Luku).
The Tanzania Electric Supply Company (Tanesco) pre-paid meters (Luku) network collapsed over the weekend, the third time this year alone.
The failure partly frustrated business and domestic life, a survey by ‘The Guardian’ has established.
Most vending stations were down for the most hours of Saturday and yesterday. Tanesco authorities have blamed the failure to hitches on the Tanzania Telecommunications Company Ltd (TTCL)’s network.
According to Tanesco, the TTCL is responsible for managing operations of the systems of its Luku vending stations.
Interviewed, some customers who endured the brunt of living in darkness for about 24 hours talked of unrecoverable losses they incurred as a result of the Luku system failure.
A Luku customer from Mwananyamala, Nuru Mhina, said on Saturday she slept in darkness and was forced to throw away some foodstuffs which were stored in the fridge.
“The food rot in my fridge because Tanesco failed to supply us power through its vending stations,” she complained.
She said the problem of network failure was now becoming common with increased occurrence.
Nuru was also very much concerned over failure of the power utility company to notify the customers on the failure.
Complaining about delays, she said: “You may go to a vending centre at 10 am and get caught in a long queue until say 12. Sometimes, we are being forced to postpone other activities just to buy power,” she said.
Another customer at Oilcom Science area Hamisi Songoro who spoke to ‘The Guardian’ while standing in queue waiting for his turn to get the service proposed that it would be better for Tanesco to return to the previous system of post-paying because the Luku system was becoming ‘cumbersome.’
“It’s very bad that the system is becoming inefficient…Tanesco should tell us what all this means and for how long this problem will continue,” a frustrated Songoro said.
Songoro said while it was true that some customers purchased power through mobile phone special services, the system covered only those with digital meters.
“They should bear in mind that a large section of customers are living in houses installed with old Luku meters which operates by using punching cards,” he said.
Tanesco Public Relations Manager Badra Masoud admitted there was problem of network on Saturday which was caused by the TTCL communication network failure.
Badra said such failures were ‘normal’ and wherever they happen customers shouldn’t worry or panic.
She said Tanesco vending stations were open 24 hours to ensure people get the service without problems or delays.
‘The Guardian’ survey established that the system went off around 2pm on Saturday until at around noon yesterday whereby customers around the City were forced to return back home without power thus incurring losses in their business.
Among the Luku centres visited include Mwananyamala Kwa Manjunju, Oilcom at Science area, BP Kijiweni at Sinza, Mwanamboka at Sinza and Komakoma at Mwananyamala.
The system failed at least twice this year alone apart from the weekend’s incident. The previous failures were attributed to attack by an unknown virus and apparent failure of the computer system.
Last September, the Luku network collapsed abruptly due to a technical fault in its main computer system controlling the pre-paid services.
Luku vending machines first came into use in Tanzania in 1995, with most of them installed in Dar es Salaam. Besides Dar es Salaam, Luku metres are in use in Arusha, Dodoma, Mara, Mwanza and Shinyanga regions and several other major urban centres.
SOURCE: THE GUARDIAN
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