Tag: floods

Catch a fire (worst year since 1816)

The extraordinary sequence of extreme weather events during the last 18 months is probably the worst run of natural disasters since 1816, when a huge volcanic eruption at Mt Tambora cooled the earth enough to cause the famous “year without a summer“, according to a powerful blog post by Weather Underground founder Jeff Masters. He runs through the list, giving details of each:

  • Earth’s hottest year on record
  • Most extreme winter Arctic atmospheric circulation on record
  • Arctic sea ice: lowest volume on record, 3rd lowest extent
  • Record melting in Greenland, and a massive calving event
  • Second most extreme shift from El Niño to La Niña
  • Second worst coral bleaching year
  • Wettest year over land
  • Amazon rainforest experiences its 2nd 100-year drought in 5 years
  • Global tropical cyclone activity lowest on record
  • A hyperactive Atlantic hurricane season: 3rd busiest on record
  • A rare tropical storm in the South Atlantic
  • Strongest storm in Southwestern U.S. history
  • Strongest non-coastal storm in U.S. history
  • Weakest and latest-ending East Asian monsoon on record
  • No monsoon depressions in India’s Southwest Monsoon for 2nd time in 134 years
  • The Pakistani flood: most expensive natural disaster in Pakistan’s history
  • The Russian heat wave and drought: deadliest heat wave in human history
  • Record rains trigger Australia’s most expensive natural disaster in history
  • Heaviest rains on record trigger Colombia’s worst flooding disaster in history
  • Tennessee’s 1-in-1000 year flood kills 30, does $2.4 billion in damage

Continue reading “Catch a fire (worst year since 1816)”

Lessons from a drowning continent: no time like the present to invest in our future

Jim Salinger’s spending the summer at the University of Tasmania in Hobart. This reflection on the lessons of Australia’s recent floods first ran in the Waikato Times at the beginning of the month, but I felt it deserved a wider audience and so with Jim’s permission reproduce it here.

As I watch from my summer roaring forties perch in Hobart, Tasmania the somewhat unprecedented rains that are deluging parts of Australia raise some pertinent lessons on climate and risk management for New Zealand. Firstly let’s look at some figures and ask the question of what are the climate mechanisms behind the deluges.

For December 2010 the Bureau of Meteorology figures show that eastern Australia (the states of Queensland, New South Wales, Victoria and Tasmania) had its wettest December on record, with an average area total of 167 mm (132% above normal). What caused Brisbane to flood were the heavy falls to the north and west between 10-12 January with totals for the three days exceeding 200 mm. In Toowoomba over 100 mm fell in less than an hour.

Further south in Victoria heavy rainfall and flash flooding occurred between 10 to 15 January, with more than 100 mm of rain across two thirds of the state. Bureau of Meteorology figures show many weather stations in Victoria have now broken their all-time January records in over 100 years of observationd: 259 mm fell on Dunolly (the previous record was 123 mm), and the 282 mm of rain that fell in 1 day at Faimouth in the north east of Tasmania – the highest 1-day total for any gauge on record for the state.

The extremely wet December had eastern Australia primed for the record floods that were to follow in January. The soil could not take any more moisture and the heavy rains turned into runoff, with record floods in some parts.

 

The causes of these floods have been laid at the feet of the La Niña climate pattern – the sister of El Niño. La Niña brings strengthened moisture-laden easterly winds on to the Australian continent. This year the La Niña event is strong, with it being amongst the top three in magnitude, ranking with the 1918/19 and 1973/74 events. However there is one distinct difference this season: temperatures in Australia this past decade have been 0.5 deg C warmer than in the 1970s, and 0.9 deg C warmer than in the 1910s, all as a result of global warming. And during the 2010/11 season, La Niña seas off eastern Australia have been much warmer than average, being 1 to 2 deg C above the 1985-1998 average.

It is a simple law of physics that a warmer atmosphere holds more moisture. With the long term heating of the oceans more moisture has been measured in the atmosphere during the last decade. The consequence is that global warming leads to an increase in the magnitude and incidence of heavy rainfall, and the resultant floods.

Global warming has arrived, and the climate has warmed. Global warming is no longer a theory…

The first lesson from the Australian flooding events is that global warming has arrived, and the climate has warmed. Global warming is no longer a theory based on abstract calculations of what the climate is very likely to do in future decades. In 2007 the Intergovernmental Panel on Climate Change (IPCC) concluded that “It is very likely that hot extremes, heat waves and heavy precipitation events will continue to become more frequent.”

The second lesson — the canary in the coal mine — is that because of global warming the frequency of these extreme weather events is only going to increase. Thus the one in 100 year high rainfall event will become far more common, with highest-ever totals being exceeded more and more often in the future.

The third lesson is that there needs to be better preparation for these events by civil society. The responsibility in New Zealand falls on local bodies through the Civil Defence and Emergency Management Act (CDEM). It’s local government that is responsible for district plans and granting developers the permission to build. Firstly should major towns be located on river floodplains? This is where there is pressure from developers. A solution is to build higher and higher flood levees but should the cost be borne by the community? Perhaps the full costs should be placed on the developer. Another option is to ban development in flood-prone areas.

However New Zealand is the lucky country in regard to the fourth lesson. We have an Earthquake Commission that covers citizens for flood damage, which Australia does not have. But insurance should be compulsory for all dwellings, to share the cost of these disasters between all citizens.

Global warming is here, now — and not a phenomenon for future generations to deal with. Thus we must embark on a course of emissions reductions targets as soon as possible, to claw back rapidly rising greenhouse gas levels in the atmosphere. If we do not act now the severity of such floods, and the subsequent loss of life and property — let alone the effect on the economy — will increase dramatically. There is no time like the present to invest in our future wellbeing.

Too many teardrops

This astonishing video was shot on Monday as flash flooding hit the Queensland town of Toowoomba after a reported 140mm of rain fell in only 30 minutes. 12 people are confirmed to have been killed in the region, and 90 more are missing according to state premier Anna Bligh. Floodwaters are rising in the state capital Brisbane, with the central business district closed down. Flood levels are expected to top out above the levels reached in 1974 — the previous record holder. I know that Hot Topic‘s readers will join me in wishing the people of Queensland well. This ABC page has a list of relief funds to which you can donate. I can confirm that Skeptical Science’s John Cook is OK, and not expecting any direct impacts. We’ll be talking to him about the floods in the next Climate Show, scheduled for recording next week.

Has global warming had an impact on this event? Watching the deniers quotes The Age saying that the floods are “consistent with (although not proof of) climate change predictions for northern Australia”, and that seems fair. The direct “cause” of the flooding is the current strong La Niña (possibly the strongest since records began, according to AMOS president Prof Neville Nicholls). This phase of ENSO causes warm water to pile up against NE Australia, helping to fuel large rainfall events. The record floods of 1974, for example, were associated with a La Niña event. To make matters worse, over the last year sea surface temperatures around Australia have been running at record levels, as this Bureau of Meteorology chart from their climate summary for 2010 shows:

The recipe seems clear enough: an intense La Niña and record sea surface temperatures combining to cause record floods. A more precise attribution of warming’s influence on the event will have to wait for the studies to be done, but for the time being it certainly looks likely that this is another extreme weather event which has been made worse by recent warming.

Update 13/1/11: Barry Brook at Brave New Climate considers the costs of the floods, and puts them in to the context of the last few years of Aussie weather extremes, and NASA’s Earth Observatory has an image showing rainfall in the Brisbane area, showing that over 200 mm fell in the flash flood regions.

[Nick Lowe]

Wake the world

This is a guest post by Anthony Giddens and Martin Rees. Giddens is a former director of the London School of Economics, a fellow of King’s College, Cambridge and the author of The Politics of Climate Change. Rees is president of the Royal Society.

This year has seen outbreaks of extreme weather in many regions of the world. No one can say with certainty that events such as the flooding in Pakistan, the unprecedented weather episodes in some parts of the US, the heatwave and drought in Russia, or the floods and landslides in northern China were influenced by climate change. Yet they constitute a stark warning. Extreme weather events will grow in frequency and intensity as the world warms.

No binding agreements were reached at the meetings in Copenhagen last December. Leaked emails between scientists at the University of East Anglia, claimed by critics to show manipulation of data, received a great deal of attention – as did errors found in the volumes produced by the UN’s Intergovernmental Panel on Climate Change. Many newspapers, especially on the political right, have carried headlines that global warming has either stopped or is no longer a problem.

Continue reading “Wake the world”

People get ready

Britain needs to step up its efforts to prepare for unavoidable climate change, according to How well prepared is the UK for climate change? the first report of the Adaptation Sub-Committee of the Committee on Climate Change— the body established by the UK’s 2008 Climate Change Act to advise government on all aspects of climate-related policy. Committee chairman Lord John Krebs summarises the thrust of the report like this:

In brief, our headline finding is that whilst the UK has started to build capacity for adaptation through advice and information to a range of public and private sector organisations, there is little evidence that this is translating into tangible action on the ground in a systematic way.

The report identifies five key areas in which early action is required.

 

From the executive summary:

  1. Taking a strategic approach to land use planning – for example to (i) ensure that new buildings and infrastructure are sited in areas that minimise exposure to flood risk, do not increase flood risk to others, and do not create a legacy of flood defence or water supply costs; (ii) manage competing pressures on land – urban, natural and agricultural – in response to a changing climate; and (iii) enhance green space where effective in the design of towns and cities to help manage surface water drainage and cope with rising temperatures and heatwaves.
  2. Providing national infrastructure (energy, water, transport, waste and communications) – for example to ensure it can cope with rising temperatures; it is resilient to potential increases in certain extreme weather events, such as storms, floods and droughts; and it takes account of changing patterns of consumer demand in areas such as energy and water use, travel and consumption.
  3. Designing and renovating buildings – for example to ensure they can cope with rising temperatures and floods and minimise water use through appropriate use of construction materials and through better design.
  4. Managing natural resources sustainably – for example by using water more efficiently; improving and extending ecological networks so that species can adapt and move as the climate changes; and making space for water along rivers and the coast.
  5. Effective emergency planning – for example by making better use of probabilistic weather forecasts to anticipate extreme weather events more effectively; creating plans that reduce impact on and ensure continuation of care for the most vulnerable groups in society during heatwaves and floods; and developing business continuity plans based on high-quality climate risk information so that businesses can cope better with disruptions to their supply chains during floods and damage to assets from severe weather.

The report’s emphasis on flooding as a major climate change impact is understandable, given the UK’s recent history. Coping with increased flooding is a key challenge for the country given the amount of development that has taken place on vulnerable floodplains. If you are at all interested in how we might plan to adapt to climate change — both the unavoidable change, the climate commitment — and the further changes we hope to avoid by mitigating carbon emissions, then this report is well worth reading. Many of the points it makes are relevant in the New Zealand context. One thing that’s worth picking out (from section 2.4, p25):

Adaptation is context specific. Unlike mitigation, where every unit of carbon has the same cost regardless of where it is emitted, the “optimal” adaptation response is context specific, depending on who is adapting, where in the country, and how they weigh up other factors in their decisions. This makes it difficult to determine in advance what successful adaptation will look like.

And there’s the rub. There’s plenty of politics in deciding how to cut carbon emissions — there’s a whole lot more in coping with unavoidable climate change. At least Britain has a body charged with looking at the big picture and advising government — something that’s sadly lacking in New Zealand. [See also BBC, Guardian]

[Al Green]