Global greenhouse gases in the atmosphere have reached an ominous milestone that is unprecedented in human history. The world’s longest measure of carbon dioxide in the atmosphere has reached 400 parts per million for the first time in three million years.
The daily CO2 level is measured at the Mauna Loa Observatory in Hawaii, which tracks greenhouse gases in the Northern Hemisphere. The level has been measured at Mauna Loa since 1958, with data before that taken from ice core samples.
The last time it reached this level, temperatures rose by between three and four degrees and sea levels were between five and 40 metres higher than today. Still sceptical? ::::
April 2013: 398.40 ppm
April 2012: 396.18 ppm
The graph shows recent monthly mean carbon dioxide measured at Mauna Loa Observatory, Hawaii. The last four complete years of the Mauna Loa CO2 record plus the current year are shown. Data are reported as a dry air mole fraction defined as the number of molecules of carbon dioxide divided by the number of all molecules in air, including CO2 itself, after water vapor has been removed. The mole fraction is expressed as parts per million (ppm). Example: 0.000400 is expressed as 400 ppm. In the above figure, the dashed red line with diamond symbols represents the monthly mean values, centered on the middle of each month. The black line with the square symbols represents the same, after correction for the average seasonal cycle.
The latter is determined as a moving average of SEVEN adjacent seasonal cycles centered on the month to be corrected, except for the first and last THREE and one-half years of the record, where the seasonal cycle has been averaged over the first and last SEVEN years, respectively. The last year of data are still preliminary, pending recalibrations of reference gases and other quality control checks. The Mauna Loa data are being obtained at an altitude of 3400 m in the northern subtropics, and may not be the same as the globally averaged CO2 concentration at the surface.
Imagine waves in the Southern Ocean half a metre higher, within this century, an Arctic ice melt 10 times as fast than just 600 years ago, warming greater than at any time during the past 10,000 years .
The rise in greenhouse gases corresponds with the extra carbon dioxide known to have been emitted by humans through fossil fuels and clearing forests.
Climate Institute chief executive John Connor says greenhouse gas concentrations have increased by about 40 per cent since the industrial revolution.
“So there’s a clear trend and a dangerous trend in carbon pollution,” he said.
Mr Connor says the worrying trend puts the planet on a path towards dangerous climate change.
“This matters because the extra heat is loading the dice for even more dangerous weather extremes and climate risk,” he said.
“We’ve already seen a lot of those with a warming of around one degree warming of average levels.
“We’re heading towards two to three and four and if you think the weather extremes have been dangerous and unsafe, then you ain’t seen nothing yet.”
A RED LIST
A team of international scientists is drawing up a “Red List” identifying ecosystems on the brink of extinction – and Australia appears eight times.
The global report is similar to what already exists for animal and plant species that are threatened, vulnerable or on the brink of extinction.
Led by a team of Australian scientists, in co-operation with the United Nations affiliated conservation body the International Union for Conservation of Nature (IUCN), the study aims to assess every major ecosystem around the world by 2025.
Twenty ecosystems around the world have been assessed so far, across six continents and three oceans.
The Coorong lagoons, Karst rising springs (Mt Gambier), coastal sandstone upland swamps (Wollongong), marshes and lakes in the Murray-Darling Basin (Warren) are listed as critically endangered.
The seagrass meadows (Spencer Gulf), the Coolibah-black box woodland (Walgett) and the semi-evergreen vine thicket (Inverell) are listed as endangered.
The red gum forests of Echuca have been listed as “vulnerable”.
Lead study author David Keith from the University of New South Wales says the system takes a broad look at ecosystems and the factors affecting them.
“For the first time we’ve really been able to put together a system of risk assessment for ecosystems at a much broader level than the species one,” he said.
“There are five criteria we use. Two are related to the characteristics of the ecosystem, how fast it is declining, and the size of the area involved.
“Two relate to the ecological functions, the biological processes and how they interact, and the characteristics of the physical climate, the water etc.
“The fifth criteria brings all those factors together”.
The scientists hope that by taking a broader look at the ecosystems in which species live, they will have more success on saving those species.
Professor Richard Kingsford from the University of New South Wales says it is an important change in approach.
“We’re just experiencing at the moment unprecedented biodiversity loss,” he said.
“Loss of plants and animal species across the world and what we’re seeing is really big impacts on ecosystems – deserts, oceans, wetlands and I guess one of the big challenges is that we need some sort of framework that doesn’t just focus on species.
“The Murray Darling Basin is one of those areas that’s been a critical issue for governments, and part of that is to understand the wetlands and the rivers and how we use the wetland area, also waterbird numbers over time, and different types of waterbirds.
“Different indicators tell us the trajectory of change over the ecosystem.”
The Coorong Lakes at the lower end of the Murray Darling Basin have long struggled with drought and diminishing flows.
David Keith says the scientists’ environmental assessment shows it’s been given a second chance.
“The colleagues who worked on that case study came to the conclusion that system was very close to collapse in recent years,” he said.
“It’s been the break in the drought and this unusually high rainfall that we’ve had in the basin catchment over the last few years that’s just pushed it back from the brink.”
The study has also classed the red gum forests of Echuca in Victoria as “vulnerable” while the seagrass meadows of South Australia have been given the status of “endangered”.
Professor Kingsford is confident that while it is a big challenge, they will have studied all the world’s ecosystems by 2025.
“I think that’s part of the great challenge and you know, the red listing of species went through a similar process,” he said.
“No body could believe that was possible. But slowly, slowly we showed that it was able to be done and the same ambition is there for this.
“It’s a fantastic thing because ecosystems really capture all the species and not just a single species, and it’s a great opportunity to have effective conservation.”
Scientists are beginning to predict how climate change will influence the height of waves.
The impact on wave height has been a neglected area of research until now.
CSIRO research scientist Mark Hemer says buoys and satellites around the world have been modelling how changes in atmospheric circulation will influence sea swells.
“We see an increase in wave heights in the Southern Ocean and we see decreases in a lot of the rest of the global oceans,” he said.
Waves in the Southern Ocean could increase by half a metre over the next century.
Dr John Hunter, from the Antarctic Climate and Ecosystems CRC, says wave height will have a similar impact on coastal areas as sea level rise.
“So changing waves and sea level can cause recession probably of order in some places say 100 metres this century,” he said.
“That’s quite likely a lot of houses are within 100 metres of the shoreline.”
For the first time wave height will be included in a new report by the International Panel on Climate Change.
Scientists from the British Antarctic Survey and the Australian National University drilled a 360-metre ice core near the northern tip of the peninsula to to identify past temperatures.
The ice core gave an extraordinary insight into the temperatures, revealing the coolest conditions, and the lowest melt, occurred six centuries ago.
By comparison, it found temperatures now are 1.6 degrees Celsius higher, and the ice melt is 10 times as fast.
The lead author of the report, Dr Nerilie Abram from the Australian National University, says the most rapid melt has occurred in the last 50 years.
“The lowest levels of melt were about 600 years ago and then the melt has increased almost tenfold over that time,” she said.
“But it’s really in the last 50 years or so that melt has increased dramatically.
“When we build the ice core we’re able to see these visual layers in the ice that we were pulling up.
“Those layers showed times when the snow had melted and then refrozen. We were able to use those to actually build up a record and look at how melting had changed over the last 1,000 years.”
Dr Abram says even the slightest increase in temperature is now having an impact.
“A lot of changes have happened in the last 50 years … there has been ice shelves [that have] collapsed, there’s been glaciers flowing faster and losing more mass, [and] more ice into the oceans,” she said.
“Summer melting is what scientists believe is causing those changes.
“To have this record that shows that even just a small amount of temperature increase now can cause a large increase in melt in this area is reason for concern.”
Dr Abram says the ice core showed that changes in the environment when the climate warms do not necessarily happen gradually.
“As the climate has warmed … the summer temperatures are getting closer and closer to that zero degrees melting threshold,” she said.
“Now, for every little bit of warming that happens, you get more days that go above that temperature … [and that] small increase in temperature can causes a very large increase in melting.”
The research paper is being published in the journal Nature Geoscience.
Scientist Agree the Change is Here to Stay
The nation’s top climate scientists and science bodies have for the first time endorsed a major report that says Australia’s climate has shifted permanently in some cases.
The peer-reviewed assessment notes that there is “strong consensus” around this central finding, and in some cases the weather has changed for good.
Last summer was by all means a record breaker, with 123 weather records broken in 90 days. As well as heat waves and unprecedented temperatures, there was heavy rainfall and major flooding. But according to the Climate Commission, this was not a one-off.
In its most comprehensive assessment analysis, the commission says Australia has a future of records yet to be broken and “in some cases day-to-day weather has shifted for good”. report author Professor Will Steffen said. “We see a pattern emerging. The south-west and the south-east of Australia have become drier – the south-west since the mid ’70s and the south-east since the mid ’90s,”
“That tells us for the future that we would expect to see dry conditions more often, more droughts in the future and very importantly we don’t expect to see the previous pre-climate-change weather conditions come back.” Professor Steffen said “To a certain extent, for a long period of time the best we can hope for, at least in terms of [our] grandchildren, is to stabilise the planet and it will stabilise at a temperature which is probably 2 degrees or more above the pre-industrial. That means some changes in patterns will lock in probably for centuries.”
In the report, the Climate Commission looks at droughts, tropical cyclones, sea-level rise, heatwaves, bushfires and heavy rainfall.
While it says the number of tropical cyclones will not increase, the influence of climate change means they will become more intense.
One-in-100-year flooding events are already becoming more common, and sea levels have risen 20 centimetres since 1880.
While there are still some questions raised about global warming and its influence, the Climate Commission hopes this report will clear the water.
All the top climate scientists in Australia have backed it, as well as the CSIRO, the Bureau of Meteorology, and the UN’s chief science body, the intergovernmental panel on climate change.
Climate Commission chief Professor Tim Flannery says the report sends a clear message.
“I think it’s really important that people understand where the debate is in climate science and where it isn’t,” Professor Flannery said. “And when you get a group like this that are endorsing or supporting this report in detail, I think that sends an important message that the scientific community is clear about these facts that we’ve laid out in this report.”
With the report warning of greater risks of more intense and severe weather, emergency service bodies are reassessing their plan of attack.
Paul Considine from the Australasian Fire and Emergency Service Authorities Council (AFAC) says its members now need to look at how their bodies are resourced, how they are staffed, and their capability to deal with the weather ahead.
“It’s important that to take on board the advice we are receiving from the experts in the field and to say given that we now need to sit down and have a think, not just in isolation but with our governments and our communities that we serve in how we react to these predicted weather events,” he said.
Our Planet’s On-track For Hottest Summers in Human History
Earth is on track to becoming the hottest it has been at any time in the past 11.3 millennia, a period spanning the history of human civilisation, a new study says.
Based on fossil samples and other data collected from 73 sites around the world, scientists have been able to reconstruct the history of the planet’s temperature from the end of the last Ice Age around 11,000 years ago to the present.
They have determined the past 10 years have been hotter than 80 per cent of the past 11,300 years.
But virtually all the climate models evaluated by the Intergovernmental Panel on Climate Change predict Earth’s atmosphere will be hotter in the coming decades than at any time since the end of the Ice Age, no matter what greenhouse gas emission scenario is used, the study found.
“We already knew that on a global scale, Earth is warmer today than it was over much of the past 2,000 years,” said Shaun Marcott, the lead author of the study, which was published in Science. “Now we know that it is warmer than most of the past 11,300 years. This is of particular interest because the Holocene spans the entire period of human civilisation.”
The data show that temperatures cooled by 0.8 degrees Celsius over the past 5,000 years, but have been rising again in the past 100 years, particularly in the northern hemisphere where land masses and population centres are larger.
The climate models project that average global temperatures will rise by 1.1 to 6.3 degrees Celsius by the end of the century, depending on the level of C02 emissions resulting from human activities, the researchers found.
“What is most troubling is that this warming will be significantly greater than at any time during the past 11,300 years,” said Peter Clark, a paleoclimatologist at Oregon State University.
Earth’s position with respect to the Sun is the main natural factor affecting temperatures during that time, the scientists said.
“During the warmest period of the Holocene, the Earth was positioned such that northern hemisphere summers warmed more,” Mr Marcott said. “As the Earth’s orientation changed, northern hemisphere summers became cooler, and we should now be near the bottom of this long-term cooling trend – but obviously, we are not.”
Other studies have concluded that human activities – not natural causes – have been responsible for the warming experienced over the past 50 years.
A report from the Federal Government’s Climate Commission says the heatwave and bushfires that have affected Australia this week have been exacerbated by global warming.
The report – Off the Charts: Extreme Australian Summer Heat – warns of more extreme bushfires and hotter, longer, bigger and more frequent heatwaves, due to climate change.
It says the number of record heat days across Australia has doubled since 1960 and more temperature records are likely to be broken as hot conditions continue this summer.
When Prime Minister Julia Gillard linked the heatwave with climate change this week, the acting Opposition Leader Warren Truss said that was utterly simplistic.
But climate change experts have no doubt that climate change is a factor in the current conditions.
The scientific advisor to the Climate Commission, Professor David Karoly, has written the report for the Climate Commission to answer questions about the link between heatwaves and climate change.
“What we have been able to see is clear evidence of an increasing trend in hot extremes, reductions in cold extremes and with the increases in hot extremes more frequent extreme fire danger day,” Professor Karoly said. “What it means for the Australian summer is an increased frequency of hot extremes, more hot days, more heatwaves and more extreme bushfire days and that’s exactly what we’ve been seeing typically over the last decade and we will see even more frequently in the future.”
Increases in extremes
Professor Karoly says climate change has worsened this heatwave by extending it and increasing its intensity.
“What climate change is doing is worsening the conditions associated with heat waves so it makes them longer, it makes the intensity of the heat wave worse and together they lead to more frequent extreme fire danger days,” he said.
Australia’s average temperature has increased by 0.9 of a degree since 1910, and the report says small changes in average temperature can have a significant impact on the frequency and nature of extreme weather events.
Professor Karoly says, based on current projections of greenhouse gas emissions and climate change, the long-term outlook is even more dire.
“We are expecting in the next 50 years for two to three degrees more warming,” Professor Karoly said. “In other words two or three times the warming we’ve seen already leading to much greater increases in heatwaves and extreme fire danger days. So we’re expecting future climate change to lead to much greater increases in extremes in the next 30 to 50 years.”
UN In No Doubt
The United Nations’s (UN) chief climate science body says there is no doubt last week’s extreme heat in Australia is part of a global warming trend.
More than 250 of the world’s top climate scientists are meeting in Hobart today to prepare the next major report from the Intergovernmental Panel on Climate Change (IPCC).
They have vowed to deliver “scientifically defensible” findings when the report is released in just over eight months’ time.
Speaking to AM, IPCC chairman Rajendra Pachauri says the world is on track for a rise in temperature of between 1.1C to 6.4C.
“Now this depends on the kind of economic growth you get, a whole lot of other drivers that would essentially lead to climate change,” Dr Pachauri said. “But if you’re going to end up towards the upper end, then that clearly is a very, very serious outcome that we’re looking at. You will get more heatwaves – we already are getting more frequent heatwaves – and we are also going to get extreme precipitation events. If you look at the trend, it’s pretty unmistakeable and any proper analysis would tell you we are heading in that direction.”
In December, a draft of the report was leaked on climate sceptic websites, in a move Dr Pachauri describes as “very unfortunate”.
“It certainly goes against the agreement that you have with the expert reviewers,” he said. “Every page of the draft report clearly carries this expectation that this is confidential, because this is a work in progress.”
Dr Pachauri says scientists are still working very hard on the final report.
“It’s entirely possible that what we get in the final version may be far stronger or in some cases maybe a little more moderate,” he said. “I wouldn’t go by any of the conclusions that people have seen as part of the draft report. But I’m absolutely certain that what we will get is a very solid, very robust and scientifically defensible report.”
He said the IPCC would look at whether there was any need to change processes in the wake of the leak.
“On the one hand we are supposed to be as open as possible and we should get as many expert reviewers as possible,” Dr Pachauri said. “In the second order draft we’ve had over 31,000 comments. We don’t want to restrict it to a point where people might say that you only get your own chosen people to comment on the report.”
But he said drafts should not be made public because they could be misleading and “may not give you the true picture of what the report will finally contain”.
He remains confident of the potential for global action on climate change.
“I am concerned, no doubt, but I also have a high opinion of human wisdom that I think at some stage we will bring about change,” Dr Pachauri said. “I mean the world did act on the Montreal Protocol, the whole problem of depletion of the ozone layer and it happened very fast. Now I expect that perhaps this, as is the case, is going to take a little longer, but hopefully we will get action across the board.”