Tuesday, January 28, 2014

More heatwave, more action required on climate change and adaptation

Melbourne and much of south east Australia is again suffering a heatwave this week. The temperature reached 41.2C in Melbourne today with a cool change bringing down temperatures on Wednesday to 25C before rising into the low to mid 30s for the rest of the week.

Inland towns get no such reprieve from the heat. Sunday in Melbourne is forecast to be 41C again, with the Bureau of Meteorology having a heatwave forecast in place.

In the first week of 2014 temperatures climbed towards 50C in a heatwave focussed on WA, Northern Territory, Queensland and NSW. It was so hot that thousands of bats fell from the trees from heat exhaustion.

The heat from Central Australia brought heatwave conditions across south east Australia, from the 13th January. Melbourne had four consecutive days of temperatures exceeding 41C, a new record for the city. The Victorian Premier Denis Napthine warned that the electricity grid was stretched to the limit and up to 100,000 people may lose power for a time.

Guest Post: Spending wisely now will make heatwaves less costly later

By Rod Keenan, University of Melbourne and Benjamin Preston, University of Melbourne

As Melbourne labours through its second heatwave this month, it is becoming clear that these events take a heavy toll. Health, energy consumption, transport, infrastructure, agriculture and other natural resources are all affected.

What is also clear is that the costs will continue to mount. The most prudent way to stop them escalating beyond our control is to spend money up front to ensure our cities and communities can withstand increasing temperatures. Put simply, we need to be more proactive, and less reactive, when adapting to climate change.

Atlantic sea surface temperatures affect Antarctic climate change

A new source of warming has been found for Antarctica: the North Atlantic and tropical Atlantic Ocean.

Warm waters in the Pacific have been connected to warming in Antarctica, but this is the first time that a connection with the Atlantic Ocean sea surface temperatures has been made.

"Our findings reveal a previously unknown--and surprising--force behind climate change that is occurring deep in our southern hemisphere: the Atlantic Ocean," says Xichen Li, a doctoral student in NYU's Courant Institute of Mathematical Sciences and the study's lead author. "Moreover, the study offers further confirmation that warming in one region can have far-reaching effects in another."

Global warming in recent decades has caused dramatic warming of the Antarctic Peninsula and West Antarctica. Changes in Antarctic climate have been attributed to greenhouse gas emissions and the ozone hole , sea surface temperatures in the central tropical Pacific warming (Qinghua Ding et al 2011) and the impact of El Nino.

Sunday, January 26, 2014

ExClimate: Climate modelling Australian climate impact scenarios

This article is a little bit of a tangent to my regular articles. I am presently doing an online course - Climate Change: Challenges and solutions - offered by the University of Exeter (UK). So please indulge me as I also use this blog for some climate course work. This article is for week 3, section 3.4 of the course on 'Your Warming World'.

The USGS provides an application, the CMIP5 Global Climate Change Viewer, for anyone to access to do research, with the proviso any results that are published should remain open and non-commercial. This application provides projections for two variables: temperature and precipitation. It can be run for annual mean or monthly results, using the mean model or a selected specific global climate model, and for different projected emissions pathways (Representative Concentration Pathways or RCP) for a particular period.

It might sound complicated, but the tool is relatively easy to use, but takes a little while to figure out all the bells and whistles. I did an initial investigation and produced some basic results, but after sleeping and some reflection decided to investigate further not only global climate model projections for the planet, but also regional projections for the South East Asia and the South Pacific and Australia in particular.

Saturday, January 25, 2014

ExClimate: Week 3.3 - Extreme events and climate Discussion

This article is a little bit of a tangent to my regular articles. I am presently doing an online course - Climate Change: Challenges and solutions - offered by the University of Exeter (UK). So please indulge me as I also use this blog for some climate course work. This article is for section 3.3 of the course on State of the climate extreme events.

1. Climate event for 2012 - Cat 4 cyclone Evan in South Pacific devastates Samoa and Fiji

Select an extreme weather event from 2012 (list provided). Does this provide further evidence of climate change or does it add more complexity to the issue?

I chose severe Tropical Cyclone Evan, a category 4 storm which devastated Samoa and Fiji in December 2012. While this particular storm was primarily part of natural climate variability, it fits the trend for more intense tropical cyclones which climate models and climate physics tells us is likely to occur.

Tropical cyclones on a global level are forecast to stay at about the same frequency, but with a greater number of intense tropical cyclones/hurricanes/typhoons occurring, according to the 2011 IPCC SREX Summary for Policymakers report.

Friday, January 24, 2014

Antarctic ice mass accelerating according to GRACE reanalysis, Pine Island Glacier in sustained retreat

The continent of Antarctica is a land of complexity and paradox, especially when talking about climate change. It is our driest and coldest desert on the planet but locks up an enormous amount of fresh water in it's thick ice sheets. The southern ocean surrounds the continent, insulating it from warmer latitudes, but those currents also bring warmer waters from the tropics to interact with the giant ice shelves around the continent.

And of course there is the paradox of Antarctic sea ice which is recording record sea ice extent over recent years due to the complex winds, currents and dynamics of melt water.

Sea ice growth or melt does not affect sea level rise. We need to look at what the great Ice sheets are doing to determine whether they are accelerating mass loss and contributing to sea level rise.

The GRACE satellites provide us with a remote measuring tool for ice mass balance, but like all tools it comes with certain biases built in. The job of the scientist is to analyse and correct for these biases.

Wednesday, January 22, 2014

Warming may spike when Pacific Decadal Oscillation moves to a positive phase

We are currently in a negative phase of the Pacific Decadal Oscillation, a cycle with phases that can last between 15 to 30 years. During a negative phase waters are cooler and heat mixes into deeper levels of the north Pacific ocean. When the next phase change ocurrs to a positive PDO we are likely to see some of the stored ocean heat released spiking atmospheric temperatures.

The Pacific Decadal oscillation was only identified by scientists in the 1990s, and we only have accurate observational data for identifying it going back some 50-60 years. Nathan J Mantua and SR Hare from the University of Washington in Seattle described the operation of the Pacific Decadal Oscillation in the Journal of Oceanography in 2002 (Mantua & Hare 2002 PDF). Read more about the PDO from the Climate Impacts Group from University of Washington.

Tuesday, January 21, 2014

Ocean Heat Content to 2000m continues warming


Ocean heat content has continued rising in the last 12 months to December 2013. This is observed in the top 700 meters of depth, as well as down to 2000 meters depth.

What pause in global warming? The Oceans take up about 93 per cent of the solar energy hitting the earth. The graphs show clearly there has been no let up in global warming, with oceans continuing to warm.

While atmospheric temperatures appear to have slowed over the last 15 years - a warming hiatus - but substantial warming is still occurring to the global system including adding heat to the world's oceans, melting Arctic sea ice, and the Greenland and Antarctic ice sheets.

Monday, January 20, 2014

ExClimate: CO2 Passing 400 parts per million, a comparison with the Pliocene

The Pliocene period, 3 to 5.3 million years ago, was the last time CO2 was at 400ppm. Investigate what the temperatures were during this time period and compare them to today. Using your knowledge from the course so far, what could explain the changes?

2013 was the first time planet Earth passed 400ppm carbon dioxide in the atmosphere since the Pliocene perod. Instruments at the Mauna Loa Observatory in Hawaii have been measuring atmospheric CO2 and other greenhouse gases for over 50 years. Other sites like CSIRO's Cape Grim observatory in Tasmania and New Zealand's National Institute of Water and Atmospheric Research (NIWA) at Baring Head Station near Wellington also take baseline measurements of atmospheric greenhouse gases.

The Keeling curve shows the rising levels of atmospheric carbon dioxide trend and is one of the most well known climate graphs. It was named after Charles Keeling from the Scripps Institute for Oceanography who started measuring CO2 at Mauna Loa in 1958 and continued up to his death in 2005. The graph clearly shows the northern hemisphere season cycle of carbon dioxide as part of the biological seasonal processes as CO2 is taken up by vegetation in Spring and Summer, then expired in Autumn and Winter, but the long term trend has been a gradual rising of CO2 by about 2ppm per year.

The significance of reaching 400ppm is that the planet has not seen this level of carbon dioxide for 3 to 5 million years, in the Pliocene Period. It was a warmer world then. By examining this geological period we can gain some insight on what we might expect to happen to temperatures, sea levels, the impact on ice sheets, and some signs of how our climate might change later this century and further into the future.

Sunday, January 19, 2014

ExClimate: The Ice Albedo Feedback mechanism and Snowball earth


This article is a little bit of a tangent to my regular articles. I am presently doing an online course - Climate Change: Challenges and solutions - offered by the University of Exeter (UK). So please indulge me as I also use this blog for some climate course work. This article is for section 2.3 of the course on Snowball earth events that have ocurred in the distant past.

No one is sure what precipitated the onset of snowball earth events. The oldest snowball earth event occurred approximately 2200 million years ago. The most recent event ended about 635 million years ago and is thought to have lasted 6 to 12 million years. Very basic life managed to survive at least the most recent snowball earth event.

The earth's orbit around the sun, it's axial tilt, and wobble all have different millenial cycles which can affect the amount of solar radiation being absorbed by the earth. Earth’s orbit changes from near circular to oval shape on a 100,000-year cycle (eccentricity). Earth’s axis is tilted and is presently at 23.5 degrees. It varies between 21.5 and 24.5 degrees every 41,000 years (obliquity - Milankovitch cycles). As the Earth spins it wobbles on its axis toward and away from the Sun over the span of 19,000 to 23,000 years (precession).

What caused the earth to go into a giant snowball is still being debated in scientific circles. A number of theories have been advanced including :

  • a reduction in solar output,
  • the Earth passing through rare space clouds,
  • a combination of high obliquity in the Earth's orbit, orbital eccentricity or precession;
  • Lithospheric weathering reducing atmospheric carbon causing planetary cooling

Thursday, January 16, 2014

Victorian Premier warns 100,000 premises may lose power during extreme heatwave


Original story by me at Climate Action Moreland

The Premier Denis Napthine warned Victorians that 100,000 premises may lose power during the extreme heatwave due to demand on the state's electricity grid. Thank you Premier, for your incompetence at managing electricity generation in Victoria.

Climate scientists have been warning of the increased frequency and intensity of heatwaves, with a long term trend of increasing temperatures and 2013 being our hottest year on record. (See this 2009 study by Alexander and Arblaster - Assessing trends in observed and modelled climate extremes over Australia in relation to future projections (PDF))

Much of the electricity system is about managing peak demand through ensuring adequate generating capacity in the network. Victoria's continued reliance on aging brown coal fired generators with impediments to diversification through renewables has let down the electors and residents of Victoria, badly. We are now seeing the results of poor climate and energy policy at the state level.

Monday, January 13, 2014

Extreme Heatwave hits Southeast Australia

This page may be updated further in coming days
Last week we saw record temperatures in a heatwave in Queensland and Western New South Wales with 34 maximum temperatures broken and mass deaths of flying foxes. The heat has been building over the last week in Western Australia and central Australia with an extreme heatwave across much of south east Australia forecast for this week.

Alasdair Hainsworth, Assistant Director for Weather Services at the Bureau of Meteorology said “What is unusual about this event, which the pilot heatwave forecast shows, is that when high maximum temperatures and above average minimum temperatures are sustained over a number of days, there is a build-up of ‘excess’ heat. Extreme heatwave conditions can be seen in southern NSW, Victoria and Tasmania."

Tess Parker from Monash University explains the dynamics of the heatwave at the Conversation: What’s cranking up the heat across south-eastern Australia?

Saturday, January 11, 2014

Climate Geo-engineering study on sulphate injection shows Hydrological disruption to rain and severe drought

While politicians have effectively dithered on robust action to reduce greenhouse gas emissions over the last 20 years we are hearing more about geo-engineering proposals to moderate rising temperatures. But the latest study from the University of Reading scientists modelling solar radiation management, and in particular atmospheric aerosol injection - one of the easiest geo-engineering proposals to do at large scale - says such a project would result in a major decrease in tropical rainfall and an increase in drought in many regional areas.

The Reading University study concentrated on the consequences on geo-engineering methods to change the solar radiation reaching the earth: through mirrors above the atmosphere; and injecting sulfate aerosols into the atmosphere to reflect solar radiation. The first could prove hideously expensive and is at the moment impractical, but the second method is quite achieveable at reasonable cost.

The study - Weakened tropical circulation and reduced precipitation in response to geoengineering (Full paper) - looks at aerosol injection in particular and the projected impacts. It was published in Environmental Research Letters.

Related: Yale Environment360: Solar Geoengineering: Weighing Costs of Blocking the Sun’s Rays (9 Jan 2014)

Thursday, January 9, 2014

Guest Post: Climate change may cut cloud cover and increase temperatures - higher climate sensitivity likely

It seems there is no silver lining in clouds as a moderating influence for a warming climate. In fact, indications are the latest research reduces some uncertainty in a crucial area, which means that climate sensitivity will be towards the higher end of the range at about 3 to 5 degrees Celsius for a doubling of atmospheric carbon dioxide. This means we are well on track to realising 4 degrees world by the end of the century. In this article from the Conversation Professor Steve Sherwood explains the importance of this research for climate sensitivity.

Related: Peter Sinclair: Happy New Year. It's worse than we thought, Climate Code Red: Warming climate may cut cloud cover, push temperatures even higher See also comments by Michael E. Mann and Gavin Schmidt at Real climate Blog: A Bit More Sensitive....

Wednesday, January 8, 2014

Risk attribution Study: Record Australian 2013 temperatures caused by climate change

Professor David Karoly and Post-doctoral researcher Sophie lewis have been undertaking analysis on the temperature record for Australia in 2013. Their article published at The Conversation - Australia’s hottest year was no freak event: humans caused it - is an attribution of risk study of the extreme Australian heat in 2013 involving statistical probability analysis. This is cutting edge climate science research using Global Climate modelling, simulations and probability analysis to determine likely cause.

Last year Lewis and Karoly examined the temperatures for the 2012-2013 Australian summer using Fractional Attribution of Risk (FAR) analysis, publishing a study - Anthropogenic contributions to Australia's record summer temperatures of 2013 (open access) - that "found that it was very likely (with 90% confidence) that human influences increased the odds of extreme summers such as 2012-13 by at least five times."

Fractional Attribution of Risk (FAR) methodologies were originally developed in epidemiology, health and population studies, and over the last few years have been applied to extreme weather events to determine the statistical likelihood of these events being substantially caused or contributed to by human caused greenhouse gas emissions and climate change. You can read background on Why bother trying to attribute extreme events? at the Real climate Blog.

2013 temperatures for Australia were off the charts claims Climate Council


The Climate Council has released it's latest report written by Professor Will Steffen: Off the Charts: 2013 was Australia's hottest year.

It draws heavily on the detail in the Bureau of Meteorology Annual Climate Statement for 2013 which I reported on, but also puts the information in context with the global trend and other scientific papers and reviews such as the IPCC Fifth Assessment Report, IPCC Working Group 1: the Physcical Science released in late September 2013.

If follows the Climate Council's first major report published at the end of 2013 on by Professor Lesley Hughes: Be Prepared: Climate Change and the Australian Bushfire Threat.

Tuesday, January 7, 2014

Mass bat deaths in record setting Queensland heatwave

Flying Foxes are dropping to earth and dying in their thousands from heat exhaustion. The extreme heat in Queensland from the 29 December to 5 January has taken a massive toll of flying fox colonies, warns a wildlife conservation organisation. It is estimated that perhaps hundreds of thousands of native flying foxes have died as a direct result of the record setting high temperatures in the heatwave event across Queensland and north western NSW.

Last year Australia suffered it's hottest year on record, with scientists claiming that extensive fractional risk attribution modelling of 2013 temperatures that this was clearly caused by human greenhouse gas emissions and climate change.

A wildlife conservation organisation, the Bat Conservation and Rescue Queensland Ltd, said that "many colonies across South-East Queensland have been severely affected including those at Camira, Mt. Ommaney, Pan Pacific Gardens, Regents Park, Boonah, Bellmere, Pine Rivers and Palmwoods. Reports indicate all Western Suburbs colonies and inland, and colonies from Gympie down to Yamanto have been devastated."

We tend to think of our own comfort and safety in extreme weather events, but animals and plants can also suffer. Heat related stress is a major cause of increased human mortality during heatwaves. But these events also impact populations of many species such as flying foxes and birds. They can't seek shelter in air-conditioned lounge rooms or shopping centres (except maybe the odd few sparrows). Instead, they fall from their tree roosts suffering heat exhaustion and dehydration.

Monday, January 6, 2014

Australian Heatwave temperatures climb towards 50C at start of 2014

With substantial heat in the continental centre, the first days of 2014 saw temperatures climb towards 50C in western Queensland, western NSW, South Australia and parts of Western Australia and the Northern Territory.

See this video report from the Guardian (3 January 2013) of bushfires on North Stradbroke Island in south east Queensland, and temperatures hitting 54C at Oodnadatta in South Australia.

Related: 2013 hottest year on record for Australia | Sea surface temperatures unusually warm around Australia in 2013

Sunday, January 5, 2014

2013 hottest year on record for Australia

Australia's Bureau of Meteorology (BOM) confirmed on 3 January 2014 in the annual climate statement that 2013 was the hottest year on record for Australia. This was all the more concerning considering the neutral ENSO conditions. 2013 also ranks as the sixth-warmest year since global records commenced in 1880, according to the WMO.

Related: Sea surface temperatures unusually warm around Australia in 2013 | 2013 was Australia's hottest year, warm for much of the world say Bureau of Meteorology scientists | SMH: Climate change: It's hot - and not just in the kitchens of bickering MPs | Alex White (Guardian): Australia swelters under a sham climate change policy after hottest year on record

Sea surface temperatures unusually warm around Australia in 2013

Sea surface temperatures around Australia in 2013 were unusually warm reported the Australian Bureau of Meteorology in it's annual climate statement. Record ocean temperatures were recorded for January and February, with November the second-highest on record. This continues a long term trend for increasing sea surface temperatures around Australia and globally.

Updates:

Friday, January 3, 2014

Volcanic activity adds further to instability of West Antarctic Ice Sheet

Volcanic activity detected near the Executive Committee range in Marie Byrd Land in West Antarctica adds another factor to the instability of the West Antarctic Ice Sheet (WAIS). A small eruption under the ice could result in melt water adding substantial lubrication to the bottom of a portion of the ice sheet, speeding up the ice stream discharge into the Ross Sea.

The West Antarctic Ice sheet is buttressed by huge ice shelves at it's edges which hold back the ice streams. Warming Southern ocean currents are melting ice shelves, causing them to retreat, allowing faster discharge of ice flows from the interior. Much of the ice sheet is grounded on a sub-glacial basin below sea level, so as the ice shelf grounding line retreats, more warm water can interact with the ice to speed the discharge and collapse of the ice sheet. Volcanic activity adds further potential instability to this process.