Xiwai International SchoolEnvironment Action ClubGlobal WarmingFebruary 23, 2011

• PPM or PPB increases are from 1750 to now

• Older data comes from sampling ice cores; newer data from direct reading

• Each GHG has different properties – strength on greenhouse effect and time in atmosphere

• The global increases in CO2 concentration are due mainly to fossil fuel use and deforestation,

while those of CH4 and N2O are primarily due to agriculture.

Source: HK Government - http://www.hko.gov.hk/climate_change/

Data is for the year 2004Non-CO2 GHGs converted to CO2 equivalent based on IPCC methodology

Source: US EPA http://www.epa.gov/climatechange/emissions/globalghg.html

Trees and plants grow by absorbing CO2 and emitting oxygen … this is why we want to plant trees … however, they are only sinks while they’re growing, and if they are burned they release CO2

There’s more carbon in the world’s soils than in all the plants and the atmosphere combined! … frozen wetlands (e.g. Russia, Canada, etc.) also hold vast amounts of methane… industrial farming can cause soils to release their carbon … warming of tundra can trigger wetlands to release trapped methane

The oceans hold more carbon than trees, plants, soils, wetlands and atmosphere combined … in fact, they absorb about 25% of the carbon we emit … but scientists aren’t sure how much the oceans can take and some say their role as a sink is weakening … the other issue is that as the oceans take up carbon they acidify

We should be alarmed about rising sea levelsFeb 18, 2011

Over a couple of centuries, [melting ice] could raise sea levels by six metres: a seemingly unstoppable process that may already be under way.… even a one-metre rise would flood the homes of around 100 million people in Asia, mostly in eastern China, Bangladesh and Vietnam … Megacities such as Shanghai, Karachi, Lagos and Bangkok would have to spend tens of billions of dollars on protecting themselves, or be submerged…