Impacts

For the first time scientists have demonstrated the impact of climate change on ocean warming and sea surface temperatures affecting global fisheries stocks. Previous studies were limited to individual fisheries. The changes have been occurring clearly since the 1970s, the scientists say. The implications of this research raises the need for timely changes in fisheries management practices and adaptation plans for communities dependant on fishing, particularly climate vulnerable developing countries in the tropics.

"Given global fisheries contribute hugely to the world's economy and food security, this is a significant finding," said co-author Dr Reg Watson from the University of Tasmania's specialist Institute for Marine and Antarctic Studies."We are no longer talking about future hypotheticals - we are talking about impacts on a global scale that we can already demonstrate."

Previous research by Dr Watson published last year demonstrated that marine fishes are now smaller in size. "Last year we showed that one of the consequences of climate change and excessive fishing is that globally marine fishes are smaller," said Dr Watson.

The paper - Signature of ocean warming in global fisheries catch - was published in Nature on 15 May 2013. The study was lead by Assistant Professor William Cheung, University of British Columbia, with collaboration from Professor Daniel Pauly and Dr Reg Watson.

I wrote about a related issue on the Velocity of climate change imperiling ocean diversity, particularly with regard to Australia, in January 2012.

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. 

Lead author Dr Megan Saunders from UQ's Global Change Institute said "Seagrass meadows not only help to slow climate change by sucking up a large portion of the world's plant-stored carbon, but they also benefit livelihoods, food security, fisheries, biodiversity, shoreline protection and other ecosystem services,"

A recent study looking into regional tropical cyclone formation conditions in the east and central Pacific has projected that 2 to 3 times more tropical cyclones (Hurricanes) are likely to hit Hawaii in the later part of this century.

Iraq has suffered decades of war with much of the social and agricultural infrastructure being damaged and now poorly maintained. Climate change was already impacting the country under Saddam Hussein with desertification and reduced river flow rates. Climate impacts of desertification, water scarcity, flood damage from more intense rain when it falls, are all taking their toll on food production. The legacy of decades of war, UN sanctions and a dictatorial regime have only added and multiplied these impacts.

James Ross island, Antarctic PeninsulaThis study analysing an Antarctic Peninsula ice core from James Ross island has determined that there has been a ten fold increase in melt intensity over the last 600 years. I reported recently that the Antarctic Peninsula summer melt season prolonged by global warming according to research from the British Antarctic Survey.

"The warming has occurred in progressive phases since about AD 1460, but intensification of melt is nonlinear, and has largely occurred since the mid-twentieth century. Summer melting is now at a level that is unprecedented over the past 1,000 years. We conclude that ice on the Antarctic Peninsula is now particularly susceptible to rapid increases in melting and loss in response to relatively small increases in mean temperature." concludes the study.

Climate change affecting safe winter chill for orchard trees. A new study says that global warming will impact fruit and nut tree productivity in Australia and globally. Most fruit and nut trees have evolved in cool temperate climates and go through a dormant winter phase and require a certain amount of winter chill to trigger their spring growth and fruit production. But with strong trends in many regions for warming winter minimum temperatures and reduced number of 'winter chill' days, the heat is on our orchards. 

Temperatures are projected to rise in most parts of the world with winter minimum temperatures projected to rise most rapidly. Our orchards have been established taking account of current climate conditions, which are now rapidly changing due to greenhouse gas pollution contributing to climate change. This will have a major impact on costs and productivity of fruit and nut orchards, an industry estimated to be worth about US$93 billion globally in 2005.

It seems the genetics of the Antarctic Octopus is showing us how fragile the West Antarctic Ice sheet (WAIS) may be with global warming. It raising questions about the ice sheet susceptibility to collapse.

The melt season on the Antarctic Peninsula has been getting much longer over the last 60 years, at some locations doubling in length according to the research lead by Dr Nick Barrand of the British Antarctic Survey. Increased melting season increases the melting stress of ice shelves which hold back significant glacier discharge and sea level rise.

Related: Global Warming on West Antarctic Ice Sheet three times the global average | Global Warming in Antarctica: Thwaites and Pine Island Glaciers accelerating, West Antarctic Ice Sheet losing mass | Waking the giant: Global Warming in the Weddell Sea, West Antarctic Ice Sheet and sea level rise | Why sea ice extent in Antarctica is growing slightly | On the brink: Penguins face an uncertain climate future

Angry Summer - 123 records broken: Image by Australian Climate Commission, 1 March 2013Melbourne is setting another temperature record: the longest number of days of any month where the maximum temperature exceeds 30 degrees Celsius.