Is Singapore getting Hotter
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As we get more and more urbanised ? Shd efforts be made to plant more trees ?
Evapotranspiration
Trees have great potential to cool cities by shading and by "evapotranspiration."
Evapotranspiration occurs when plants secrete or "transpire" water through pores in their leaves--in a way, plants sweat like people do. The water draws heat as it evaporates, cooling the air in the process. A single mature, properly watered tree with a crown of 30 feet can "evapotranspire" up to 40 gallons of water in a day, which is like removing all the heat produced in four hours by a small electric space heater. -
it must be a global effort.. sg alone doesn't help much...
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URBAN CLIMATE
By Sam C M Hui, Ph.D., Department of Architecture.
Urban areas have particular climatic conditions with a higher temperature than exposed country-side, weak winds and an amount of sunshine that varies according to the degree of pollution, the urban density, the orientation of the streets and the shade provided by other buildings.
Urban Microclimates
Urban microclimates are complex because of the number and diversity of factors which come into play. Solar radiation, temperature and wind conditions can vary significantly according to topography and local surroundings. In addition, layout density can provide further constraints: the precise plot division, the need for access and privacy, and the noise and impact of atmospheric pollution must all be taken into account.
In winter, most urban microclimates are more moderate than those found in suburban or rural areas. They are characterised by slightly higher temperatures and, away from tall buildings, weaker winds. During the day, wide streets, squares and non-planted areas are the warmest parts of a town. At night, the narrow streets have higher temperatures than the rest of the city. In summer, green spaces are particularly useful in modifying the environment during the late afternoon, when the buildings are very hot inside.
Strong local winds can modifiy the temperature distribution described above. Usually winds in towns are moderate because of the number and range of obstacles they face. However, a few configurations such as long straight avenues or multi-storey buildings can cause significant air circulation. Tall buildings rising above low-rise building can create strong turbulent wind conditions on the ground as the air is brought down from high levels. Strong winds can flow through gaps at the base of tall buildings. To protect pedestrians from this, the turbulent flow has to be prevented from descending to street level, for example by modifying the building form or by using wide protective canopies. In semi-open areas, adjacent buildings can be used as protective screens against some winds.
Urban Heat Island
Visit any city on a hot summer day, and you will feel waves of blistering heat emanating from roads and dark buildings. Stay in the city past nightfall, and you will notice that the streets are still radiating heat, while surrounding rural areas are rapidly cooling.
Almost every city in the world today is hotter - usually between 1 to 4 deg C hotter - than its surrounding area. This difference between urban and rural temperatures is called the "urban-heat-island" effect", and it has been intensifying throughout this century. During hot months a heat island creates considerable discomfort and stress and also increases air-conditioning loads and the incidence of urban smog (do you notice this in Hong Kong!). Research shows that for every degree of increased heat, electricity generation rises by 2% to 4 %, and smog production increases by 4% to 10%. People also believe there is a direct link between global warming and urban heat islands. First, the greenhouse effect could aggravate rising urban temperature significantly. Second, heat islands may contribute to the greenhouse effect.
In general, there are three main factors causing the urban heat islands:
Surface - The characteristics of the surfaces in urban and rural areas are different and their thermal properties also differ a lot. As compared with rural areas, urban districts have high absorption (of the heat of the sun and atmosphere), low reflection, low evaporative heat loss and fast transmission of heat.
Heat emission - "Artificial heat" emitted in urban districts is much higher than that in rural areas.
Air quality - Air pollution in urban areas is high and the particulates will form a shield for trapping heat. -
I see more and more trees kena chopped liao, and contruction going on..plus every little grass space is covered with concrete now...
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yah.....getting hot
tts why u see our pre-pubescent girls right up to the aunties all wearing less and less -
thats true. Whenever trees are cut down there is no replanting.Originally posted by laurence82:I see more and more trees kena chopped liao, and contruction going on..plus every little grass space is covered with concrete now...
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Hahahaha! yeah someone quick write a post to blame gahmen quick !!
not enough trees gahmen's fault oso. must complain more!
temp rising should blame gahmen....they are at fault for not being able to persuade USA to sign kyoto treaty. US uses 25% of the world's energy leh with less than 5% of world's population! so sg at fault!! hahahaha
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Taking care of the enviroment is part of the govt's job. There's a department call Nparks tat takes care of that. Temperature in built up areas is higher than in countryside. Its proven in scientific studies. More greenery is good for us. Plant more trees. Have more rooftop gardens.Originally posted by SilverKris:Hahahaha! yeah someone quick write a post to blame gahmen quick !!
not enough trees gahmen's fault oso. must complain more!
temp rising should blame gahmen....they are at fault for not being able to persuade USA to sign kyoto treaty. US uses 25% of the world's energy leh with less than 5% of world's population! so sg at fault!! hahahaha -
Taking care of the enviroment is part of the govt's job. There's a department call Nparks tat takes care of that. Temperature in built up areas is higher than in countryside. Its proven in scientific studies. More greenery is good for us. Plant more trees. Have more rooftop gardens.
aiyah...i oso know all that and i oso agree with your points...national parks (under ministry of national devpt), ministry of environment, tree planting day and all that. but as everyone who studies singapore geography knows....some places like chinese garden or japanese garden the responsibility of jtc. so not every tree on every road, or every bush in housing estate, or every bladee of grass under nparks lah.
taking care of environment oso not totally under nparks since environment can oso refer to sea/river water quality, air/noise quality pollutionn etc. but seriously hor, i have been to the big cities in us, europe and melbourne....sg is very deserving of its garden city image where urban areas are concerned. small territory populated by more than 4 million, but greenery everywhere. my american friend oso told me bukit timah reserve has more flora and fauna species than entire north american continent. i dont believe...so check website...wah lau he wass right! one nature reserve here can have more types of plants than usa/canada combined! make me damn paiseh.
oso...i agree that temp in city higher than countryside.....global warming due to industrialization...but george bush dont seem to care or believe leh..never sign kyoto treaty. so long as big countries like usa and australia who use a lot of energy resources refuse to sign, global warming will continue....and even if usa decide to sign tomorrow, it will take close to a century for the ozone to recover.
singaporeans can still do their part even if other countries dont..no need to wait for gahmen to complain first...per capita level, we are BIGGGGGGGGGGG contributors of cfc...each singaporean can switch on aircon LESS OFTEN, thereby reducing energy consumption. but here damn hot leh, u can do it a not? i try only lah...but cannot tahan, switch on a while hehehehehehehehehehehehehe
p.s. wah lau...this is my longest posting everleh!!!!!!!!!....but i am an environment freak! -
singaporeans can still do their part even if other countries dont..no need to wait for gahmen to complain first...per capita level, we are BIGGGGGGGGGGG contributors of cfc...each singaporean can switch on aircon LESS OFTEN, thereby reducing energy consumption. but here damn hot leh, u can do it a not? i try only lah...but cannot tahan, switch on a while hehehehehehehehehehehehehe
can't help you here
don't have air con to switch off -
Here's some facts I have been noting over the past 5 years.
Each year, local temperature rises by about 1 degree, starting from year 2000, highest temp was usually between 31 - 33. Now a days we're looking at 34 and higher.
Coastal tides rises higher now then compared to 5 years ago. Rainy season don't come around the expected time of year, and have "shifted" somewhat to sometime around December and drags on till January/February.
Our polar ice-caps are melting an inch a year, this adds to total sea level increments. Venice is the first one to eventually become submerged.
Maybe some of you will be tempted to ask me for proof, but simply do a search with Googles on "global warming", and you'll see scientific data collected through various on-going research on global warming, and therein, you'll see the disturbing truth. -
just imagine that we are living in some futuristic setting like in sci fi movies like that, everywhere only got skyscrapers, no trees. must be 50 degree celsius
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Go to HK in the summer you will find buildings with reflective glass reflecting heat away from the building (keeping inside cool and not overloading the aircon) and all aircon exhaust, car, buses and trucks exhaust, all heat on the streets!! You not only feel the heat, you feel baked in between the tall buildings, your "pi sai" is black after standing on the streets for a while. But, Hong Kongers will say, where can we go, Hong Kong is so small? It should be a global effort but who can tell the American to follow the Kyoto Protocol to reduce waste emissions? I often wonder why america with its value of democracy and human right cannot see the need to protect environment in which human live? This is a big, global issue.Originally posted by hopy:it must be a global effort.. sg alone doesn't help much...
After I return from Shanghai and Hong Kong in August, I am actually convinced that singapore is not that hot. But with 4 seasons, people in shanghai can take the heat much better because they know a few months later they would have their balls frozen. How hot is hot may be a matter of perspective. Thats life!! -
We are part of the world also and we can contribute our bit to combat global warming. I think the trees do help. If there were no trees along Orchard Rd or CBD area we would be baking in the sun as we walk along the pavement. The trees and plants help to beautify the city also.Originally posted by hopy:it must be a global effort.. sg alone doesn't help much... 