Climate Change: no comprende (continued)
MEASURING CO2 LEVELS.
There are hundreds of monitoring stations worldwide that measure and monitor atmospheric CO2 levels. The Global Atmosphere Watch (GAW) program, of the World Meteorological Organisation(WMO), is a partnership involving 80 countries. It provides reliable scientific data and information on the atmosphere, and the natural and man-made changes that occur within it.
For periods before 1958, air bubbles trapped in polar ice cores are used to determine CO2 levels. Over the last 10,000 years, before the Industrial Revolution, the levels of CO2 were pretty stable – 275 to 285 parts per million. But since the industrial revolution, the levels of CO2 in the atmosphere have increased by about 100 parts per million. At the moment, the amount of CO2 in the atmosphere is increasing by around 15 gigatonnes every year.
Of course, nature reduces our impact on climate by absorbing more that half of our CO2 emissions (thankyou, nature). The amount left over is called the “airborne fraction”. Since 1958 it’s been sitting at around 45%. Deforrestation, however, reduces the planet’s ability to naturally absorb CO2 – as such, deforrestation is another human activity which contributes to increased CO2 volume in the atmosphere. Thank goodness trees are a renewable resource (for now, anyway).
CO2 & THE GREENHOUSE EFFECT.
Scientists expectation that increased atmospheric CO2 will absorb more infrared radiation as it escapes back out to space is based on decades of lab experiments and radiative physics. A study of data collected by two satellites (NASA’s 1970 IRIS satellite and Japan’s 1996 IMG satellite) found that CO2 in the atmosphere absorbs more infrared radiation as it escapes back out to space, i.e. it does indeed have a greenhouse effect.
OUR CARBON EMISSIONS – some stats.
Using publications containing historical energy statistics from 1751 onward, The Carbon Dioxide Information Analysis Center (CDIAC) has estimated that about 337 billion tons of carbon have been released to the atmosphere from the consumption of fossil fuels and cement production. Half of these emissions have occurred since the mid 1970s.
The 2007 global fossil-fuel carbon emission estimate is 8365 million metric tons of carbon. It represents an all-time high, and a 1.7% increase from 2006.
Liquid and solid fuels accounted for 76.3% of the global emissions from fossil-fuel burning and cement production in 2007. Combustion of gas fuels (e.g., natural gas) accounted for 18.5% (1551 million metric tons of carbon) of the total global emissions from fossil fuels in 2007.
Since the 1970s, emissions from cement production (377 million metric tons of carbon in 2007) have more than doubled. They now represent 4.5% of global CO2 releases from fossil-fuel burning and cement production.
These were the top 10 Total Fossil-Fuel CO2 Emissions emitting countries in 2007:
(1) People’s Republic of China (Mainland) (1899-2007)
(2) United States of America (1800-2007)
(3) India (1858-2007)
(4) Russian Federation (1992-2007)
(5) Japan (1868-2007)
(6) Germany (1792-2007)
(7) Canada (1785-2007)
(8) United Kingdom (1751-2007)
(9) South Korea (1945-2007)
(10) Islamic Republic of Iran (1902-2007)
Australia came in at #16 (1860-2007).
In terms of Per Capital emissions, Australia is ranked #12. China was #70, The US was #11 and India was #142.
3. HOW DO WE KNOW OUR CARBON EMISSIONS ARE CAUSING OR CONTRIBUTING TO CLIMATE CHANGE?
Ok, this is where my understanding really wanes.
I have read that scientists measuring the type of carbon accumulating in the atmosphere observe that the type of carbon that comes from fossil fuels is more numerous. I don’t, however, know how they observe this.
I’ve also heard that these observations have been backed up by measurements of the levels of oxygen in the atmosphere (falling oxygen levels). And that carbon found in coral records several centuries old shows that there has been a steep rise in the type of carbon that comes from fossil fuels. But I don’t know who has conducted these studies. Yet.
So, that’s it. That’s all I know about the science. Not much, but it’s a start.
I’ll endeavour to find out and improve my knowledge on the evidence of human-induced climate change in the months & years to come. It seems to me that it is becoming increasingly important for average citizens to understand the scientific evidence and let that guide their political and lifestyle decisions, as the forces opposed to climate change action (particularly action of the economic variety) ramp up their efforts to kill this as a political and moral issue, in order to preserve the status quo.
I’ll leave you with a clip of David Attenborough and Professor Peter Cox from his documentary The Truth About Climate Change. Here they explain a graph similar to the one that convinced David of the reality of climate change: