Feed aggregator
Rule-maker wants all new generation to be smarter, quicker
What does Finkel mean for community power?
APA takes step closer to big wind-solar energy park in W.A.
Public consultation on the Landfill Gas method crediting period extension review
Public consultation on the Landfill Gas method crediting period extension review
Victoria agribusiness turns to 196MW wind farm with 20MW storage
Chimps' strength secrets explained
Final Climate of the Nation report
CEFC invests in lithium mine to help make Australia storage powerhouse
Contributions to sea-level rise have increased by half since 1993, largely because of Greenland's ice
Water mass enters the ocean from glaciers such as this along the Greenland coast. NASA/JPL-CaltechContributions to the rate of global sea-level rise increased by about half between 1993 and 2014, with much of the increase due to an increased contribution from Greenland’s ice, according to our new research.
Our study, published in Nature Climate Change, shows that the sum of contributions increased from 2.2mm per year to 3.3mm per year. This is consistent with, although a little larger than, the observed increase in the rate of rise estimated from satellite observations.
Globally, the rate of sea-level rise has been increasing since the 19th century. As a result, the rate during the 20th century was significantly greater than during previous millennia. The rate of rise over the past two decades has been larger still.
The rate is projected to increase still further during the 21st century unless human greenhouse emissions can be significantly curbed.
However, since 1993, when high-quality satellite data collection started, most previous studies have not reported an increase in the rate of rise, despite many results pointing towards growing contributions to sea level from the ice sheets of Greenland and Antarctica. Our research was partly aimed at explaining how these apparently contradictory results fit together.
Changes in the rate of riseIn 2015, we completed a careful comparison of satellite and coastal measurements of sea level. This revealed a small but significant bias in the first decade of the satellite record which, after its removal, resulted in a slightly lower estimate of sea-level rise at the start of the satellite record. Correcting for this bias partially resolved the apparent contradiction.
In our new research, we compared the satellite data from 1993 to 2014 with what we know has been contributing to sea level over the same period. These contributions come from ocean expansion due to ocean warming, the net loss of land-based ice from glaciers and ice sheets, and changes in the amount of water stored on land.
Previously, after around 2003, the agreement between the sum of the observed contributions and measured sea level was very good. Before that, however, the budget didn’t quite balance.
Using the satellite data corrected for the small biases identified in our earlier study, we found agreement with the sum of contributions over the entire time from 1993 to 2014. Both show an increase in the rate of sea-level rise over this period.
The total observed sea-level rise is the sum of contributions from thermal expansion of the oceans, fresh water input from glaciers and ice sheets, and changes in water storage on land.
IPCC
After accounting for year-to-year fluctuations caused by phenomena such as El Niño, our corrected satellite record indicates an increase in the rate of rise, from 2.4mm per year in 1993 to 2.9mm per year in 2014. If we used different estimates for vertical land motion to estimate the biases in the satellite record, the rates were about 0.4mm per year larger, changing from 2.8mm per year to 3.2mm per year over the same period.
Is the whole the same as the sum of the parts?Our results show that the largest contribution to sea-level rise – about 1mm per year – comes from the ocean expanding as it warms. This rate of increase stayed fairly constant over the time period.
The second-largest contribution was from mountain glaciers, and increased slightly from 0.6mm per year to 0.9mm per year from 1993 to 2014. Similarly, the contribution from the Antarctic ice sheet increased slightly, from 0.2mm per year to 0.3mm per year.
Strikingly, the largest increase came from the Greenland ice sheet, as a result of both increased surface melting and increased flow of ice into the ocean. Greenland’s contribution increased from about 0.1mm per year (about 5% of the total rise in 1993) to 0.85mm per year (about 25% in 2014).
Greenland’s contribution to sea-level rise is increasing due to both increased surface melting and flow of ice into the ocean.
NASA/John Sonntag, CC BY
The contribution from land water also increased, from 0.1mm per year to 0.25mm per year. The amount of water stored on land varies a lot from year to year, because of changes in rainfall and drought patterns, for instance. Despite this, rates of groundwater depletion grew whereas storage of water in reservoirs was relatively steady, with the net effect being an increase between 1993 and 2014.
So in terms of the overall picture, while the rate of ocean thermal expansion has remained steady since 1993, the contributions from glaciers and ice sheets have increased markedly, from about half of the total rise in 1993 to about 70% of the rise in 2014. This is primarily due to Greenland’s increasing contribution.
What is the future of sea level?The satellite record of sea level still spans only a few decades, and ongoing observations will be needed to understand the longer-term significance of our results. Our results also highlight the importance of the continued international effort to better understand and correct for the small biases we identified in the satellite data in our earlier study.
Nevertheless, the satellite data are now consistent with the historical observations and also with projected increases in the rate of sea-level rise.
Ocean heat content fell following the 1991 volcanic eruption of Mount Pinatubo. The subsequent recovery (over about two decades) probably resulted in a rate of ocean thermal expansion larger than from greenhouse gases alone. Thus the underlying acceleration of thermal expansion from human-induced warming may emerge over the next decade or so. And there are potentially even larger future contributions from the ice sheets of Greenland and Antarctica.
The acceleration of sea level, now measured with greater accuracy, highlights the importance and urgency of cutting greenhouse gas emissions and formulating coastal adaptation plans. Given the increased contributions from ice sheets, and the implications for future sea-level rise, our coastal cities need to prepare for rising sea levels.
Sea-level rise will have significant impacts on coastal communities and environments.
Bruce Miller/CSIRO, CC BY
John Church previously received funding from Australian Climate Change Research Program.
Christopher Watson receives funding from the Australian Research Council and the NCRIS Integrated Marine Observing System.
Matt King receives funding from Australian Research Council and Department of Environment.
Xianyao Chen received funding from the National Key Basic Research Program of China and the Natural Science Foundation of China.
Xuebin Zhang received funding from Pacific Climate Change Science Program (PCCSP) and follow-up Pacific-Australia Climate Change Science and Adaptation Planning program (PACCSAP) both of which were funded by the Australian Government’s International Climate Change Adaptation Initiative, and also from Australian Climate Change Science Programme (ACCSP), National Environmental Science Programme (NESP), and Centre for Southern Hemisphere Ocean Research (CSHOR).
What happens when you're sleep deprived?
Hong Kong launches bill to ban domestic ivory trade
The move follows demonstrations in the city and the decision by China to ban their own trade
Hong Kong has launched a landmark bill to ban its domestic ivory trade, amid accusations that authorities were lagging behind China in phasing out the market.
Hong Kong is home to the world’s biggest retail ivory market, with more items for sale than anywhere else in the world. The majority of buyers are mainland Chinese, who smuggle the worked ivory across the border. Hong Kong is also perpetuating the illegal market: more than a third of licensed ivory dealers have been found to advise buyers on ways to smuggle ivory out of the city, according to a recent report by Traffic.
Continue reading...Hundreds of US mayors to vote on switch to renewable energy by 2035
Leaders from more than 250 cities gathered at the US Conference of Mayors in Miami Beach to vote on a resolution to reach a 100% clean energy goal
Mayors meeting in Florida are considering an ambitious commitment to have US city governments run entirely on renewable sources such as wind and solar by 2035.
Related: New Orleans mayor: US climate change policy cannot wait for Trump
Continue reading...Blue shark in shallow waters on Mallorca beach - video
A blue shark caused panic on Saturday after being seen by bathers close to the beaches of Cala Major and Can Pastilla. The animal was captured on Sunday, with local media reporting that it was suffering from a head wound, possibly caused by a harpoon
Continue reading...Rhino breeder to auction 500kg of horns in South Africa
John Hume to take advantage of court ruling allowing domestic sales of horns, despite international ban
A rhino breeder in South Africa is planning an online auction of rhino horns to capitalise on a court ruling that opened the way to domestic trade despite an international ban imposed to curb poaching.
The sale of rhino horns by breeder John Hume, to be held in August, will be used to “further fund the breeding and protection of rhinos”, according to an auction website.
Continue reading...Hard Brexit could halt Heathrow expansion plans, experts say
National Infrastructure Commission says UK must maintain ties with EU to save key projects such as third runway and HS2
A hard Brexit would be a “calamity” that would spell the end for the Heathrow expansion, according to the chairman of the National Infrastructure Commission.
While the airport has argued that Brexit makes its third runway ever more important, Andrew Adonis said private investment in infrastructure would be off the table unless Britain could maintain ties with the EU.
Continue reading...Macron meets Schwarzenegger and vows to stop oil and gas licences
In a dig at Trump’s climate change inaction, French president welcomes the green campaigner and says there will be ‘no new exploration licences’
The new French government has sought to further burnish its green credentials with the announcement it is to stop granting licences for new oil and gas exploration.
In his first major intervention since Emmanuel Macron’s election victory, the ecological transition minister, Nicolas Hulot, told the broadcaster BFMTV there would be “no new exploration licences for hydrocarbons”.
Continue reading...Tanzania presses on with hydroelectric dam on vast game reserve
Stiegler Gorge dam on the Selous park, a world heritage site listed as ‘in danger’, will cause irreversible damage, say conservationists
Plans to build a huge hydroelectric dam in the heart of one of Africa’s largest remaining wild areas have dismayed conservationists who fear that the plans will cause irreversible damage to the Selous game reserve in Tanzania.
After many years of delays and false starts, last week the president of Tanzania, John Magufuli, announced that he would be going ahead with the Stiegler’s Gorge dam on the Rufiji river. Magufuli, nicknamed “the Bulldozer”, was elected in 2015 in part on his record of successful road and infrastructure building. The dam will provide 2,100MW of electricity to a country that is currently extremely undersupplied: Tanzania, with a population of approximately 53m to the UK’s 65m, has just 1,400MW of installed grid capacity compared to the UK’s total grid capacity of 85,000MW.
Continue reading...New study confirms the oceans are warming rapidly | John Abraham
Although there’s some uncertainty in the distribution among Earth’s ocean basins, there’s no question that the ocean is heating rapidly
As humans put ever more heat-trapping gases into the atmosphere, the Earth heats up. These are the basics of global warming. But where does the heat go? How much extra heat is there? And how accurate are our measurements? These are questions that climate scientists ask. If we can answer these questions, it will better help us prepare for a future with a very different climate. It will also better help us predict what that future climate will be.
The most important measurement of global warming is in the oceans. In fact, “global warming” is really “ocean warming.” If you are going to measure the changing climate of the oceans, you need to have many sensors spread out across the globe that take measurements from the ocean surface to the very depths of the waters. Importantly, you need to have measurements that span decades so a long-term trend can be established.
SpaceX completes launch and landing double bill
Pages
