Global Warming and Climate Change
Global Warming is the increase in temperature of the earth's atmosphere.
Climate Change, in this context, is the effect of warming or cooling on the Climate.
The change in weather patterns. The amount and location of precipitation (rain, hail, snow), desertification, intensity of storms, ocean level rising or lowering, size of polar ice caps, change in the amount of (permanent) snow on top of mountains etc.
Based on the definition, there is always, has always been and will always be, Climate Change.
Whether or not there is Global Warming is up for debate.
But before you can answer that you need to ask:
The average, near-surface atmospheric, temperature rose 0.6 ± 0.2 °Celsius in the 20th century.
(This statement is based on the observed increase in the average temperature of the Earth's atmosphere and oceans in recent decades.
Additional evidence for global climate change can be gleaned from observational and satellite records of precipitation over land areas in middle latitudes and in the tropics, areal extent of snow cover, date of snow cover disappearance in the Arctic, trends in sea-ice extent in the Arctic and Antarctic regions, melting of glaciers outside the polar zone, and sea-level rise.)
So the answer to the first question, "Is there Global Warming", is: Yes.
(The next question frequently asked is:
"Is it man made?" as if this would make a difference to the consequences.
Therefore the answer to that is: "Who cares!")
But that gives rise to other questions:
Is Global Warming something we should worry about?
Just because there is a change, that does not necessarily mean it is bad.
So, before we can answer that, we should ask more questions:
"Are the consequences of an increase in temperature really all that bad?"
There are some who argue that an increase in temperature is beneficial or that an increase in CO2 level would promote plant growth.
Another question should be: "Is the increase likely to continue, stabilize or even reverse if we continue with whatever it is we are doing?"
If the answer to that is yes, then that poses even more questions.
We will try to answer these questions in a balanced way, based on the available (scientific) information, both observable facts and forecasts.
We will try to set aside the politicking and vested interests. (This is not an easy task, so if you feel we have made an error, please let us know, with your sources in making your case)
Then, as always with our party, you make up your own mind.
We have established, based on measurements, that there is Global Warming.
However, there is an ongoing dispute as to what causes Global Warming.
- Increase in solar activity
- Volcanic emissions
- An increase in concentration of greenhouse gases (man-made or otherwise)
We will address these in turn: But bear in mind:
Irrespective of which one of these is the greatest contributor, the simple fact is that the concentration of man-made greenhouse gases is the only one we have some control over.
An increase in solar activity would lead to an increase in infrared radiation, which is absorbed by the greenhouse gases, leading to an increase in temperature.
Solar irradiance changes have been measured reliably by satellites for only 30 years.
These precise observations show changes of a few tenths of a percent that depend on the level of activity in the 11-year solar cycle.
While a component of recent global warming may have been caused by the increased solar activity of the last solar cycle, that component was very small.
Furthermore, the Sun is once again less bright as we approach solar minimum, yet global warming continues.
releases about 130 to 230 million metric tonnes (145 million to 255 million short tons) of carbon dioxide each year.
Volcanic releases are about 1% of the amount which is released by human activities (27 billion metric tonnes CO2 in 2004).
Although volcanoes do emit (a comparatively tiny amount of) heat, the main contribution to the Global Warming is through the release of CO2, a greenhouse gas.
However, when volcanoes erupt they also blast a great amount of ash and sulphur-rich gases into the stratosphere.
Sulphur Dioxide combines with water vapour in the stratosphere to form dense clouds of tiny sulphuric acid droplets.
These droplets take several years to settle out and they cause a decrease of the troposphere temperatures because they reflect solar radiation and scatter it back to space.
In fact, large volcanic eruptions can impact global climate, by reducing the amount of solar radiation reaching the Earth's surface, lowering temperatures in the troposphere.
When Mount Pinatubo erupted in the Philippines June 15, 1991, an estimated 20 million tonnes of sulphur dioxide (SO2) and ash particles blasted more than 12 miles (20 km) high into the atmosphere.
Gases and solids injected into the stratosphere circled the globe for three weeks.
The 1980 eruption of Mt. St. Helens lowered global temperatures by 0.1 deg Celsius.
The 1815 Tambora eruption, the largest in recorded history, ejected some 50 cubic kilometres of magma.
The volcanic cloud lowered global temperatures by up to 3 degrees Celsius.
Even a year after the eruption, most of the northern hemisphere experienced sharply cooler temperatures with snow and ice during the summer months.
In parts of Europe and in North America, 1816 was known as "The year without a summer."
As a result crops failed and soup kitchens were opened to feed the hungry.
increase the overall temperature of the earth, by absorbing infrared radiation and trapping this heat like a blanket.
An increase of greenhouse gases effectively creates a thicker blanket, leading to an increase in temperature.
Greenhouse gases include water vapour, carbon dioxide, methane, nitrous oxide, chlorofluorocarbons (CFC's), hydrochlorofluorocarbons (HCFC's), hydrofluorocarbons (HFC's), perfluorocarbons (PFC's), and ozone in the lower stratosphere and troposphere.
While water vapour has the largest effect, its concentrations are not directly affected, on a global scale, by human activities.
Human activities, for example:
combustion of fossil fuels, deforestation, rice cultivation, mining, the use of nitrogen fertilizers, refrigerants, and solvents have all contributed to increases in greenhouse gases in the atmosphere.
Internationally accepted science indicates that increasing concentrations of greenhouse gases ultimately will raise atmospheric (air) and oceanic (sea water) temperatures and could alter associated circulation and weather patterns. Many greenhouse gases have long atmospheric residence times - several decades to centuries - which means that the atmosphere will recover very slowly, if at all.
Carbon Dioxide CO2 .
Since the start of the Industrial Revolution (late 1800s), the concentration of atmospheric CO2 has increased by approximately 110 µL/L or about 40%.
Most of this increase was released since 1945.
Monthly measurements taken at Mauna Loa Hawaii since 1958 show an increase from 316 µL/L in that year to 376 µL/L in 2003, an overall increase of 60 µL/L during the 44-year history of the measurements.
Update: 2008 this increased to 385 µL/L (parts per million (ppm)).
Update: 2009 this increased to 387 µL/L.
Update: 2010 this increased to 389 µL/L.
Update: 2011 this increased to 391 µL/L.
What is the cause of this increase?
Burning fossil fuels such as coal, petroleum and natural gas is the leading cause of increased man-made CO2.
Around 27,000 million tonnes of CO2 are released per year (2004) worldwide, equivalent to about 7360 million tonnes of carbon.
(Conversion: multiply by 12 (atomic weight of Carbon) then divide by 44 (molecular weight of CO2)).
Deforestation is the second major cause.
But others, like the production of cement involving the calcination of limestone, are significant contributors.
(In this process, limestone (Calcium Carbonate, Ca-CO3) is heated to drive off CO2 to form lime (Calcium Oxide, CaO)).
Globally, liquid and solid fuels accounted for 77.5% of the emissions from fossil-fuel burning in 2004.
Combustion of gas fuels (e.g., natural gas) accounted for 18.1% (1434 million metric tons of carbon) of the total emissions from fossil fuels in 2004 and reflects a gradually increasing global utilization of natural gas.
Emissions from cement production (298 million metric tons of carbon in 2004) have more than doubled since the mid 1970s and now represent 3.8% of global CO2 releases from fossil-fuel burning and cement production.
Gas flaring, which accounted for roughly 2% of global emissions during the 1970s, now accounts for less than 1% of global fossil-fuel releases.
Methane CH4 is a potent greenhouse gas. (Natural gas contains primarily Methane).
Considering only its heat-absorption potential, one molecule of methane has 20 times more effect on our climate than one molecule of carbon dioxide.
Global concentrations of methane in the atmosphere have more than doubled over the last two centuries.
Scientists have concluded that atmospheric increases in methane are largely caused by increasing emissions from man-made sources, such as landfills, agricultural activities, fossil fuel combustion, coal mining, the production and processing of natural gas and oil, and wastewater treatment.
Methane is also produced naturally via anaerobic decomposition.
Wetlands provide the largest natural source, followed by termites.
While termites are only a trivial natural methane source in temperate zones, they are ubiquitous in the tropics and when tropical forests are logged or burned, vast quantities of wood residue provide ideal conditions for termite population explosions.
In the north of Russia are the massive Siberian permafrost regions.
Frozen peat bogs, which collectively cover an area of roughly 603,000 square kilometres.
If a regional Arctic warming trend thaws the bogs, it will cause the trapped gases, vast quantities of CO2 and Methane,
to be released into the atmosphere contributing to even more global warming.
In 1964 the first "solid" natural gas (Methane Hydrate) was discovered in Russia and in the 1970s methane hydrate was found in ocean sediments.
To date, methane hydrate has been detected around most continental margins.
Worldwide, estimates of the natural gas potential of methane hydrate approach 400 million trillion cubic feet -- a staggering figure compared to the 5,500 trillion cubic feet that make up the world's currently proven gas reserves.
Today, the U.S. Geological Survey estimates that methane hydrate may, in fact, contain more organic carbon than all the world's coal, oil, and non-hydrate natural gas combined. NETL
This turns out to be both a blessing and a curse.
If captured, Natural gas (Methane) has proven to be a reliable and efficient energy source.
Methane is less polluting than other fossil fuels and is the least carbon intensive.
However, if it thaws, as a result of Global Warming, and escapes into the atmosphere, it will add to Global Warming, which in turn will lead to more melting etc.
Nitrous Oxide N2O.
Nitrous oxide, commonly known as laughing gas, is a potent, stable greenhouse gas with a long atmospheric lifetime, from 120 to 150 years.
Although actual emissions of nitrous oxide are smaller than those of carbon dioxide, nitrous oxide is approximately 270 times more powerful than carbon dioxide at trapping heat in the atmosphere over a 100-year time horizon.
The primary source of nitrous oxide emissions is agricultural fertilizer use and soil management.
Lesser sources include fossil fuel combustion, nitric acid productions, and burning of agricultural crop residues.
In addition to Nitrous Oxide (N2O) there are several other forms of oxides of Nitrogen: Nitric Oxide (NO) and Nitrogen Dioxide (NO2) being the most common, and N2O3, N2O4 and N2O5.
There is some disagreement on whether the effects of global warming will be beneficial or detrimental.
Again, just because there is a change, it does not necessarily follow that it is bad (for humans or the environment).
Many researchers predict disastrous consequences for a warming of 1.5 to 7 °C.
Some others point to the facts that the earth has been a lot warmer and colder in the past and feel that the environment will adapt.
They are more than likely right.
However, the question is not whether the ecosystems can adapt or not.
The question should be: Can the ecosystems adapt in time?
In the past climate change appears to have been more gradual.
A lot of marine species are already living at the upper end of their temperature tolerance.
Any further increase in temperature now, could wipe them out.
Over a longer period of time, they would adapt.
However, due to the speed of this global warming, they might not have enough time to acclimatize.
Rising temperatures are beginning to have a noticeable impact on ecosystems.
Secondary evidence of global warming — lessened snow cover, rising sea level, weather changes — provides examples of consequences of global warming that may influence not only human activities but also the ecosystems. Increasing global temperature means that ecosystems may change; some species may be forced out of their habitats (possibly to extinction) because of changing conditions, while others may flourish.
With increasing average global temperature, the water in the oceans expands in volume, and additional water enters them which had previously been locked up on land in glaciers, for example the Greenland and the Antarctic ice sheets. An increase of 1.5 to 4.5 °C is estimated to lead to a rise of 15 to 95 cm.
Many of the world's largest and most prosperous cities are on the coast, and the cost of building better coastal defences (due to the rising sea level) is likely to be considerable.
Some Pacific Ocean island nations, such as Tuvalu, (population about 12 thousand ) are concerned about the possibility of an eventual evacuation, as flood defences may become economically unviable for them. Tuvalu already has an ad hoc agreement with New Zealand to allow phased relocation.
In the 1990s a variety of estimates placed the number of global environmental refugees at around 25 million.
The Intergovernmental Panel on Climate Change (IPCC), which advises the world’s governments under the auspices of the UN,
estimated that 150 million environmental refugees will exist in the year 2050, due mainly to the effects of coastal flooding,
shoreline erosion and agricultural disruption.
The total surface area of glaciers worldwide has decreased by 50% since the end of the 19th century.
Currently glacier retreat rates and mass balance losses have been increasing in the Andes, Alps, Himalayas, Rocky Mountains and North Cascades.
As of March 2005, the snow cap that has covered the top of Mount Kilimanjaro for the past 11,000 years since the last ice age, has almost disappeared.
The melting waters of these glaciers is a large and reliable source of fresh water.
Many of the world's major rivers are dependant on this water during the dry season.
Increased melting would cause greater flow for several decades, after which some areas of the most populated regions on Earth are likely to simply 'run out of water'.
Some scientists fear that the Gulf Stream, which conveys warm water from the Caribbean Sea across the Atlantic Ocean to northern Europe, and is partly responsible for the relative mildness of northern Europe's climate, could be reduced or stopped altogether by the decreased salt content of sea water resulting from global warming.
This could then result in another Ice Age, affecting most of Northern Europe and North America.
There are consequences of an increase in Carbon Dioxide, apart from an increase in temperature:
Carbon Dioxide, when mixed with water, forms a weak acid.
Because of the increase of CO2 in the atmosphere, the oceans of the world are gradually becoming more acidic.
So, what's the problem?
Corals form their skeletons out of limestone.
The acidification of seawater by carbon dioxide is threatening to stop corals from growing and could potentially dissolve, or seriously weaken existing reef structures.
Coral reefs are more than just pretty to look at.
Coral reefs reduce the energy of waves breaking on tropical coastlines and serve as a buffer for coastal communities from storms, wave damage and erosion, thereby protecting homes and lives.
In the case of tsunamis, this can mean the difference between surviving and perishing.
Coral Reefs provide an economic benefit in the form of tourism.
They are full of new and undiscovered biomedical resources. They are the world’s richest repositories of marine bio diversity harbouring millions of animals and plant species that play a key role in the global food web. They are the largest living structures on earth, visible from space.
Corals already live on the upper edge of their temperature tolerance. Abnormally high water temperatures combined with low winds and still water can cause destructive bleaching, and if it continues, dying of coral reefs.
There are two major accelerating effects: The first one involving trees, the second one: polar ice caps.
Rising Global temperature causes forest fires to occur more frequently and on a larger scale.
This in turn releases more stored carbon into the atmosphere which then leads to a further increase in temperature etc.
This would lead - some would say has already led - to greater carbon emissions than the carbon cycle can naturally re-absorb.
In addition to that, bush fires result in a reduction of the total overall forest area on the planet,
the very thing that can reduce the Carbon-Dioxide in the atmosphere.
Normal Carbon Cycle - in balance.
When you take away some of the trees,
Less CO2 gets absorbed.
2. Polar Ice Caps:
With global warming, the water of the oceans will get warmer.
As a consequence, some parts of the polar ice-caps will melt.
Whilst the ice largely reflects the sun rays back into space, the oceans absorbs heat from the sun.
Thus, retreating sea ice will allow the sun to warm the now exposed sea water, contributing to further warming.
This then leads to more ice melting, etc.
In addition to this; some of the algae that live in the ocean, may not be able to survive the higher temperatures.
The algae take up as much CO2 as the trees do.
This would then again lead to even higher temperatures, more ice melting etc.
Some people feel that up to 1.5 °C of warming would result in an increase in crop yields and stabilize the weather.
They argue that replacement forests would grow more rapidly and that, in the northern hemisphere,
there would be a northward migration of forests as northern latitudes become more suitable (cooler) climates for sustaining forests.
Increasing average temperature and carbon dioxide can have the effect, up to a point, of improving ecosystems' productivity.
Atmospheric carbon dioxide is rare in comparison to oxygen.
(CO2 equals less than 1% of air, compared to O2 which equals about 21% of air. Nitrogen (N2) makes up about 78%).
However, IPCC models predict (and experiments being conducted at universities at this moment indicate)
that higher CO2 concentrations would only spur growth of flora up to a point.
In many regions the limiting factors for accelerating grows are water and/or nutrients, not temperature or CO2.
After only a marginal increase in temperature and CO2 concentrations, the greenhouse effects and warming would continue but there would be no compensatory increase in growth.
You should be aware that many of the skeptics of the "anthropogenic (man-made) global warming theory" have links to the fossil fuels industry and are funded by them.
Many observers are critical of the connections between global warming contrarians (The Skeptics) and the petroleum and coal industries.
At the very least, there is a suggestion of a conflict of interest; since many policies which might be used to combat human-caused global warming might adversely affect the profits of these corporations.
To be fair, most opponents have been considered skeptics, or at least somewhat skeptical of certain points, long before the funding by the petroleum and coal industries was provided.
By now most people will accept that we are entering a period of global warming.
Irrespective of whether the warming is caused by an increase in solar activity, volcanic emissions, and/or an increase in concentration of greenhouse gases,
the only cause of warming we can do something about is the production of greenhouse gases.
We can either reduce the amount released into the atmosphere, or increase the amount being taken out.
Ways of Reducing Greenhouse gases:
Energy efficiency - Turning off lights and appliances when not in use.
Insulating building from cold or heat.
Fuel switching - Minimize the use of coal fired power stations, use natural gas instead.
Process re-engineering - If you have to use coal, use it with the most efficient turbines.
Capture the CO2 when it comes out of the flue and use sequestration to store it underground.
Use more efficient heat-exchangers and turbines.
Stop the "flaring" of the gas, associated with oil extraction.
In Russia and Nigeria, 150 billion cubic metres of gas is burnt off or `flared’ every year - before it even leaves the gas fields.
This practice is adding 350 million tonnes of CO2 per year into the atmosphere.
This valuable gas should be captured and used for energy production, like it is in the rest of the world.
At the present It's not, because of economics.
The magnitude of this is better illustrated when you realize that the 20 billion litres of petrol used in Australia per year produces 45 million tons of CO2.
Contrary to commonly held belief (It cost too much to change), reports from organizations which have achieved significant reductions in their greenhouse gas emissions, indicate that their actions have in fact been beneficial to their bottom line.
It is important to realize that fuel efficiency doesn't directly relate to emissions causing pollution.
Rather, it depends on the fuel source used to drive the vehicle concerned.
A vehicle driven on biofuel may use more litres of fuel over a given distance, but it would produce near zero net emissions when compared to a petrol driven car.
A car run on electricity, although appearing to be "clean", may in fact produce a lot of greenhouse gas when that electricity is produced in a traditional fired coal generator.
The atmospheric pollution is no longer ‘at site’, but rather at a distant power station.
On the other hand, a hybrid vehicle does reduce the amount of fuel used and therefore the amount of greenhouse gases released. see What's a Hybrid.
Grow more trees.
It sounds (too) simple, but trees are a very easy and cost effective way of taking carbon dioxide out of the atmosphere.
Much cheaper than carbon sequestration, a process that uses energy to put the CO2 underground. (Out of sight, out of mind?)
How much greenhouse gas does Australia produce?
Australia produces about 1.29 % of all global greenhouse gas emissions.
In recent years China has overtaken the United States as the greatest contributor of greenhouse gas.
in 2005 China's emissions were 16.4 % and the USA 15.7% of global CO2e emissions.
 For those who want to do the calculation themselves:
20 Billion litres of petrol with a weight-density of 737.22 kg/m3 equals 14.744 billion kg.
Assuming an average formula for petrol C8H18
1 kg of petrol produces 3.09 kg CO2.
=> 14.744 Billion kg of petrol times 3.09 equals 45.559 Billion kg or 45.559 million tonnes.
 Carbon Dioxide Information Analysis Center (CDIAC) - Fossil-Fuel CO2 Emissions (1751 - 2006)
 IPCC - Climate Change 2007:Synthesis Report An Assessment of the Intergovernmental Panel on Climate Change.