gizmo_2655 wrote on Dec 9^th, 2010 at 9:15pm:


The major one would be the "heat island" effect around cities. The concrete and asphalt of cities retains the heat making them hotter than the surrounding countryside.

Another one would be deforestation which causes lower humidity, less cloud cover and as a result higher temperatures.

An increase in snow cover reflects more heat and causes even greater snow cover. Some of our ice ages have started this way.

So there are 3 examples off the top of my head and I haven't even mentioned greenhouse gasses

The_Barnacle wrote on Dec 9^th, 2010 at 9:57pm:


I would add that the hardstand roof, paving and road surfaces also contribute to devastating temperature rises in watercourses due to heated stormwater run-off - because most native aquatic fauna cannot tolerate a daily variation in temperature of more than 2^oC...

Equitist wrote on Dec 9^th, 2010 at 10:08pm:


Those are all good points..Although the 'heat island' effect would hardly be large enough to increase temperatures on a 'planetary' scale..

And due to the physics of cooling, the stormwater run off wouldn't even come close to increasing the temperatures of watercourses by any decent percentage of A degree, let alone by 2 degrees on a daily basis..

And again, deforestation would only have a local effect....still not enough to influence WORLD temperatures by any perceptable amount...

If you remove ALL forest from the planet, then maybe you'd get a noticeable increase in world temp..

So again, none of those would have a large enough influence (even combined) to be responsible for the current natural climate variation, or to even affect it to point where the 'checks and balances' of the Earth couldn't cope ..

http://rainforests.mongabay.com/0907.htm

ATMOSPHERIC ROLE OF FORESTS

                 
     Global Carbon Emissions Breakdown
           Gigatons
Global Emissions:            8.7-9.1
Fossil fuels:            6.9-7.0
Land-use change (deforestation):            1.8-2.0
Other:            0.1
Global Absorption:            8.7-9.1
Remains in atmosphere:            4.5
Absorbed by oceans:            2.3
Absorbed by vegetation:            1.9-2.3


Global Carbon Reservoirs
Carbon
Reservoir            Size
(Gigatons)
Atmosphere            750
Forests            610
Surface oceans            1,580
Deep ocean            38,100
Fossil fuels            5,000
Coal            4000
Oil            500
Natural gas            500
Natural gas            500
Source: Kasting 1998


Rainforests play the important role of locking up atmospheric carbon in their vegetation via photosynthesis. The vegetation and soils of the world's forests contain about 125 percent of the carbon found in the atmosphere. When forests are burned, degraded, or cleared, the opposite effect occurs: large amounts of carbon are released into the atmosphere as carbon dioxide along with other greenhouse gases (nitrous oxide, methane, and other nitrogen oxides). The burning of forests releases about two billion metric tons of carbon dioxide into the atmosphere each year, or about 22 percent of anthropogenic emissions of carbon dioxide.

The buildup of carbon dioxide and other gases in the atmosphere is known as the "greenhouse effect." The accumulation of these gases is believed to have altered the earth's radiative balance, meaning more of the sun's heat is absorbed and trapped inside the earth's atmosphere, producing global warming. Greenhouse gases like carbon dioxide are transparent to incoming shortwave solar radiation. This radiation reaches the earth's surface, heats it, and re-radiates it as long-wave radiation. Greenhouse gases are opaque to long-wave radiation and therefore, heat is trapped in the atmosphere. As greenhouse gases build up, this opacity is increased and more heat is trapped in the atmosphere.

The largest anthropogenic contributor to the greenhouse effect is carbon dioxide gas emissions, about 77 percent of which comes from the combustion of fossil fuels and 22 percent of which is attributed to deforestation. The final 1 percent comes primarily from energy-costly production activities like the manufacture of concrete, steel, and aluminum. The preindustrial atmospheric concentration of carbon dioxide was 280 ppm, though today levels have risen to 375 ppm, a 30 percent increase. Climatologists estimate that a level pf 450 ppm—as projected for 2050—may result in an eventual 1.8-3 degrees Celsius (3.2-5.4 degrees Fahrenheit) increase in temperature. Some scientists predict that global warming will produce a sharp upswing in global temperatures followed by a deep plunge into a glacial period several thousands years from now. However, there are still a lot of unknowns about the impact of climate change.

The extent and effect of global warming has been long debated by scientists, industries, and politicians. In 1995 leading scientists and the Intergovernmental Panel on Climate Change (IPCC) concluded that global warming had been detected and that "the balance of evidence suggests a discernible human influence on global climate." Their evidence included a 0.5-1F (0.3 to 0.6C) increase in average global temperature since 1960, a 4.5F (2.5C) degree increase at the Earth's poles, the breaking up of the Antarctic ice sheets, the receding of glaciers worldwide, the longest El Niño ever recorded, a record number of hurricanes in 1995, a record number of heat waves, and an increase of epidemics attributed to global climate change, including dengue fever, malaria, hanta virus, and the plague. According to scientists at the National Oceanic and Atmospheric Administration, 1998 was the warmest year on record, although 2005 was a close second. A British study at the University of East Anglia suggested that 1998 may be the warmest year in over 800 years. The 1990s have been the warmest decade of the millennium and the past decade has witnessed nine of the eleven hottest years this century. In the 900 years before the twentieth century, temperatures dropped an average of 0.02 degrees C (0.04 degrees F) per century.

Since 1960 atmospheric carbon-dioxide levels have increased from 313 ppm to 375 ppm (20 percent increase), according to measurements from Mauna Loa observatory, and carbon-dioxide levels are now 27 percent higher than at any point in the last 650,000 years. The Intergovernmental Panel on Climate Change (IPCC) projects that atmospheric carbon-dioxide levels could reach 450-550 ppm by 2050, possibly resulting in higher temperatures and rising sea levels, along with a myriad of potential impacts ranging from increased storm and hurricane intensity; melting of polar ice, Arctic permafrost, and glaciers; changes in ocean currents including the Gulf Stream; a rise in global sea levels which could inundate low-elevation cities like Cairo, Venice, Lagos, New Orleans, and Amsterdam and cause problems for low-lying nations; increased coral bleaching and mortality of reef ecosystems; changes in ecosystems; species migration and mass extinction, especially among cold climate species; heightened danger from human pollutants like ozone; health impacts including the spread of tropical disease into cooler climates and range expansion of other pathogens; and water shortages.

Israeli forest fire sign of climate change: study



Israel's worst-ever forest fire earlier this month confirms predictions on the impact of global warming in the Mediterranean basin, according to one of Israel's leading climate experts.

"The fire disaster in the Carmel Mountains near Haifa is a taste of the future," Guy Pe'er, co-author of Israel's National Report on Climate Change, said on Wednesday.

Nearly a decade ago, Pe'er and other scientists warned that warming would create conditions such as heat waves, decreased and delayed rainfall, leading to a higher risk of intense forest fires.
Advertisement: Story continues below

The recent four-day blaze, which destroyed some five million trees across 12,000 acres (4,800 hectares), arose from these very conditions, he said.

The national report predicted that a temperature increase of only 1.5 degrees Celsius (2.7 degrees Fahrenheit) compared to pre-industrial times would cause the region's desert to expand northward some 300-500 kilometers (200-30 miles).

Without deep cuts in global greenhouse gas emissions, the temperature increase by century's end will be closer to 3.0 C (5.4 F), scientists say.

In either scenario, such a change would spell the end of Mediterranean-type ecosystems in Israel, Pe'er said.

The fire that raged in the Carmel mountain range, which rises more than 500 metres (1,500 feet) above sea level, was preceded by eight months of drought and occurred during a heat wave with temperatures around 30 C.

Normally, first rainfall should have come in September or October, and the maximal daily temperature at this time of year should be around 15-20 C.

Pe'er, currently a fellow at the Helmholtz Centre for Environmental Research, Leipzig, said it would be decades before the region began to recover.

More than 40 people were killed in the fire.



http://news.smh.com.au/breaking-news-world/israeli-forest-fire-sign-of-climate-change-study-20101210-18rmn.html



Another 40 deaths the Liberal Party is partially to blame for?

Miss Anne Dryst wrote on Dec 10^th, 2010 at 4:49am:



I could be wrong but didnt they arrest two boys for starting the Israel fires???which then got out of control probably because of no burn back orders..

missy you are better at this than me.. but what about forest fires dont they destroy" trees "in particular?????.. California comes to mind.

also mud slides.. avalanches. floods.. all destroy forests..and have been doing so for millions of years.. infact I believe I read somewhere where thats where our fossil fuel all began.with a tree falling down. that could be myth of course!!!!!! lol

it amuses me to see our environmentalists all flying to an airconditioned   Cancun and home again.having been  feted with the best of everything.
whilst producing bacically nothing, that couldnt have been achieved via Skype... skeptic dead right I am..


I also find it even more amusing that.. the FIFA.. has chosen Qatar as a destination for the World Cup where every stadium will be airconditioned.and all people of any note will be flying back and forth  probably in private jets.. all this 10 years from now....

if we live long enough to witness it, that is!.. Bondi will be lost to the ocean because of those damn Libs by then, and thats just for starters.

Miss Anne Dryst wrote on Dec 10^th, 2010 at 6:30am:


Greenies have always been liars.

Miss Anne Dryst wrote on Dec 9^th, 2010 at 6:17pm:

You still here mellie, so you lied when you said you weren't posting here anymore.