Posts tagged "carbon dioxide"

IPCC special: Long-term climate projections

Chapter 12 of the 5th Assessment Report of IPCC (Intergovernmental Panel on Climate Change) deals with future projections of climate change in the long-term. Long-term in this case means beyond the middle of the 21st century when the projections start to depend more strongly on the pathway or scenario of emissions of greenhouse gases, principally CO2. We rely extensively on computer models of the climate system for this as, obviously, there are no observations of the future. While computer models are not completely accurate in their ability to project future climate change, it is possible to use our understanding of the climate system to assess uncertainties...

Measuring Greenhouse Gases

It is not at all trivial to make precise measurements of greenhouse gas concentrations in the atmosphere, but exactly this is needed when assessing climate change impacts from human emissions. Only when present concentrations are known as accurately as possible can long-term trends be identified and seasonal variability be studied. The three most important greenhouse gases in the atmosphere are carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Several clean air measuring stations around the world, with Mauna Loa the most well known, form a global network to monitor atmospheric concentrations. One of these stations is Baring Head, close to Wellington in New Zealand....

Wildfire: recycled sunlight or fuel for climate change?

The rainforest is burning in Sumatra, Indonesia. A majestic Meranti tree is close to the fire line. As flames from the surrounding canopy rage closer to this ancient tree, water quickly evaporates from its leaves, transforming the foliage into dry fuel for the fire. When turbulent, convective winds within the canopy bring hot air to the immediate surroundings of our tree, long-chain cellulose molecules in the desiccated foliage begin to crack, producing hydrocarbon gases and solid char deposits; with a flash, the gases ignite, forming the flames of the fire. This brief, catastrophic episode at the end of this tree’s life quickly re-balances a century...