Rebuilding soils through carbon sequestration and mitigating fossil fuel emissions sounds like a win-win solution all around. A reason the Liberal and National Parties in Australia adopted it as a major part of their 2010 Direct Action climate change policy. But a new international study by Australian and UK scientists said soil carbon programs while important, have many limitations, and provide too much false hope in mitigating emissions from fossil fuels.
To most of us, what is hidden beneath the waves of our coastal environment remains invisible and is little thought about or cared about. Yet seagrass meadows, though hidden from our direct view, contribute valuable ecological services supporting valuable fish nurseries, as food for dugongs and turtles, and as a highly efficient blue carbon sink sequestering carbon.
A new study of the seagrass meadows in Moreton Bay, Queensland found that a significant proportion of valuable seagrass habitats would be lost without action to offset the affects of climate change. "The area of seagrass habitat was predicted to decline by 17% by 2100 under a scenario of SLR of 1.1 m." said the study.
Leading Queensland environmental scientists are up in arms over changes to Queensland's Vegetation Management Act and the Water Act which will enhance land clearing and destruction of native vegetation important for preserving biodiversity values, ecological services such as clean water and flood mitigation, and carbon sink potential.
Coastal Wetlands are under pressure. They face rising seas from climate change, but their biggest obstacle to migrate naturally inland is human development with roads, houses and other infrastructure blocking their way. And our urban planners are largely unaware of this tricky situation.
UNESCO's International Day for Biological Diversity on May 22 focussed strongly on conserving our marine diversity. One of the important marine ecosystems are the seagrass meadows around the coasts of the world. A new global scientific research study just released has shown that seagrass meadows store significantly more carbon than any land based forest. They are very important as carbon sinks. But they are also suffering a major decline due to pollution from agricultural and mining development and chemical runoff, coastal development changing water turbidity upsetting photosynthesis in seagrass, and increasing sea surface temperatures affecting seagrass growth due to global warming.
The new global study of seagrass meadow ecosystems has found that coastal seagrass beds store much more carbon than can be stored in even the most carbon dense forests, such as the temperate native forests of Victoria. Seagrass meadows can store up to 83,000 metric tons of carbon per square kilometre, mostly in the soils below them. In comparison, a typical land forest stores around 30,000 metric tons per square kilometre mostly as wood. It is the first global study to analyze the carbon storage capacity in seagrasses.
The carbon sink capacity of urbanized river estuary and coastal environments to mitigate climate change has reduced by 100 fold according to scientists from the University of Technology Sydney. The Scientists used core samples from Botany Bay in Sydney to reconstruct the sedimentation changes in the past 6000 years, highlighting the changes in the ecology. The plant samples in the sedimentation changed as rapid industrialisation occurred around Botany Bay during the 1950s.
"We have effectively gone back in time and monitored carbon capture and storage by coastal ecosystems, finding a 100-fold weakening in the ability of coastal ecosystems to sequester carbon since the time of European settlement. This severely hampered the ability of nature to reset the planet's thermostat." said Dr. Peter Macreadie, University of Technology, Sydney Chancellor's Postdoctoral Research Fellow.