From drought to floods in Northland

Following a devastating drought in Northland they have now had bad flooding. The lack of feed supplies on farms will make dealing with the floods more difficult, and the lack of grass will result in a muddy mess for farmers.

RNZ: Northland floods leave homes uninhabitable, farms under water

As the flood waters recede in Northland the full extent of the damage from the weekend’s deluge is becoming clear.

After months of near-crippling drought more than 200mm of rain fell over 10 hours from Friday night.

The main road into Kaitaia remains closed by massive slips.

The Waiharakeke Stream near Kaikohe has slowed to a raging torrent after bursting its banks and flowing into the small town of Moerewa.

Most people have been able to return to their homes, often to find them caked in mud and strewn with debris, and some are uninhabitable.

Moerewa residents are becoming sadly accustomed to the floods, which seem to come every couple of years now.

I heard this one referred to as a 500 year flood, which seems like an arbitrary label, but it highlights the severity of this flood.

There’s a vast plain between Whangārei and Kawakawa could almost be mistaken for a lake if it wasn’t for the tops of fence posts and the farm houses on raised ground surrounded by water.

Minister of Civil Defence Peeni Henare visited the region yesterday and said it would be a few days yet before the full extent of the damage is known.

Floods closed some of the region’s water treatment plants and Whangārei Mayor Sheryl Mai said residents are being asked to conserve water for the next few days.

“The quality of the water coming into the treatment plant is just awful and it takes a lot longer to treat that water.

Once the extent of the damage understand more clearly the councils will talk to central government about long-term solutions for flood prevention and repairs to infrastructure, she said.

It’s bad, but it will take time to determine how bad. It will take some time to deal with the damage, and flood prevention wil be a longer term and very difficult project.

 

Storms, floods and climate change

Inevitably when there are large scale storms and floods the issue of climate change comes up. It’s difficult to attribute single weather events to large scale long term changes, but it’s easy to see an association.

If there is more heat in the oceans and if there is more heat in the atmosphere then storms are more likely, and more of them will be bigger.

There has been a lot of news coverage of hurricane Harvey in the US and the very heavy rains and widespread flooding in Texas. President Trump has said  ‘Nobody’s seen anything like this’ – he is prone to exaggerating but he could be right:

WP: Catastrophic flooding ‘beyond anything experienced’ in Houston and ‘expected to worsen’

“Catastrophic flooding in the Houston metropolitan area is expected to worsen,” the National Weather Service said Sunday. It added: “This event is unprecedented and all impacts are unknown and beyond anything experienced.”

But Texas isn’t the only place there have been floods recently.

FloodsGlobalWarming

South Asia floods: Mumbai building collapses as monsoon rains wreak havoc

Flooding across India, Nepal and Bangladesh leaves parts of cities underwater as storm moves on to Pakistan

Across the region more than 1,200 people are feared to have died and 40 million are estimated to have been affected by flooding in India, Nepal and Bangladesh.

Vast swaths of land are underwater in the eastern part of the Indian state of Uttar Pradesh, where more than 100 people have reportedly died, 3,097 villages are submerged and almost 3 million villagers have been affected by flooding, according to officials. Army personnel have joined rescuers to evacuate people from the area.

The storm reached Pakistan on Thursday, lashing the port city of Karachi, where at least 14 people have died, and streets have been submerged by water.

Sierra Leone mudslide and flood leaves more than 1,000 people dead

More than 1,000 people have died from the mudslide and flood that hit Sierra Leone’s capital nearly two weeks ago, a local leader and a minister have said during services honouring the disaster’s victims.

Thousands of people living in areas at risk during heavy rains have been evacuated.

Niger Reports 44 People Killed in Floods

At least 44 people have been killed in floods caused by torrential rains this season in Niger.

No single storm or flood can be directly linked to climate change, but an increasing number of increasingly severe floods could.

HOW CLIMATE CHANGE CONTRIBUTED TO MASSIVE FLOODS IN SOUTH ASIA

Heavy monsoon rains have caused disastrous floods and left millions displaced in South Asia. Like Harvey, climate change likely played a role.

“This is not normal,” Reaz Ahmed, the director-general of Bangladesh’s Department of Disaster Management, told CNN. “Floods this year were bigger and more intense than the previous years.”

Climate change appears to be intensifying the region’s monsoon rains. Rising sea surface temperatures in South Asia, for example, led to more moisture in the atmosphere, providing this year’s monsoon with its ammunition for torrential rainfall—much the same way abnormally high water temperatures in the Gulf of Mexico intensified Harvey before it stalled over Texas.

Warmer air temperatures in high latitude regions of the globe have also increased glacier melt, which has, in turn, raised the Himalayan rivers’ water levels and heightened the risk of flooding.

Heavy Flooding and Global Warming: Is There a Connection?

Climate change increases the probability of some types of weather. Recent heavy rains and flooding in the Northeast, Midwest, and Great Plains are consistent with a warming planet, and such events are expected to become more common over time.

As average temperatures in regions across the country have gone up, more rain has fallen during the heaviest downpours. Very heavy precipitation events, defined as the heaviest one percent, now drop 67 percent more precipitation in the Northeast, 31 percent more in the Midwest and 15 percent more in the Great Plains, including the Dakotas, than they did 50 years ago.

This happens because warmer air holds more moisture.

Two things are inevitable, rain and climate debate.

Flooding, states of emergency

 

Cyclone Debbie moved west from the Pacific onto Australia and then south, causing serious flooding in a numbers of places in Queensland and northern New South Wales.  The remnants then headed sought east across the Tasman and has now reached New Zealand.

It is now causing flooding up and down the North Island and is going to drag some of the the rain down the east of the South Island.

After flooding and landslips a state of emergency has been declared in Rangitikei and and also in Whanganui, and there is also flooding in Auckland.

Heavy rain warnings are still in place for much of the North Island. The rain band will track south but shouldn’t be as bad in the South Island.

RNZ has a a summary of ‘what you need to know’ including…

MetService said there was a risk of flash flooding in Auckland, and there were heavy rain warnings for much of the central North Island, including Gisborne, Coromandel, Hawke’s Bay and Taranaki, as well as Auckland and Wairarapa.

and has a live blog here.

 

Greens use Dunedin to highlight major climate problem

The Greens have linked the heavy rain in Dunedin on Wednesday to climate change. In Question Time in Parliament yesterday Green co-leader Metiria Turei started with these questions.

1. METIRIA TUREI (Co-Leader—Green) to the Minister for Climate Change Issues : Does he agree that local authorities will face greater adaptation costs and find it more expensive to protect infrastructure and property as the climate changes; if not, why not?

A reasonable question – “as the climate changes” is debatable but most science suggests it may get warmer and with more extreme weather events.

Metiria Turei : Does the Minister agree with the Intergovernmental Panel on Climate Change editor Professor Blair Fitzharris that as global warming continues, Dunedin is likely to face more extreme rainfall events, storm surges, and extreme winds, and that low-lying, densely populated areas, coastal communities, and major transport infrastructure, including Dunedin Airport, are particularly at risk?

These are important points that we would expect the Greens to raise.

Metiria Turei : Does the Minister agree with Dunedin City Council’s submission on New Zealand’s climate change target, which says “More effective mitigation could significantly reduce potential future adaptation costs” and that “the Government should consider investing more in climate change mitigation”; if not, why not?

The Dunedin City Council is fairly Green leaning so this is no surprise. But it’s highly questionable whether the Government can do anything that would significantly alter any effects of climate change – New Zealand’s emissions are a very small proportion of global emissions and reducing emissions here by 40% as the Greens want is likely to make a very small difference at best.

Metiria Turei : How does the Minister justify the National Government’s record on climate change, which shows a 13 percent increase in net greenhouse gas emissions, to the people of Dunedin and to the Mayor of Dunedin, Dave Cull, who said today “There may be some areas with sea level rise that we end up retreating from and not putting any more infrastructure in and actually taking the buildings out of. That is the challenge going into the future with climate change.”?

That would be a major for Dunedin, which has large flat areas – reclaimed swamp – that are inhabited. These include South Dunedin, St Kilda and St Clair, plus much of the Taieri Plains. If Dunedin “retreated” from those areas it would more than decimate the city.

Metiria Turei : Is the Minister taking into account increased adaptation costs for local councils when determining New Zealand’s emissions reduction target, given that the Dunedin City Council estimates that engineering options to protect private property and infrastructure in high-risk areas against a 0.3 metre rise in the sea level will cost around $10 million, and that protection against a 1.6 metre rise in the sea level will cost around $150 million?

If these “increased adaptation costs” prove to be necessary it is going to be regardless of what New Zealand does with emissions. We have a minute effect on world climate systems.

Metiria Turei : By not taking urgent leadership on climate change, has his Government not abandoned the Dunedin City Council and the people of Dunedin to pick up the cost of more extreme rainfall events like yesterday, when the city was swamped in 24 hours by 2 months’ worth of rain, causing flooding, electricity outages, sewerage overflows, the evacuation of rest homes and schools, the Otago Peninsula being cut off, and which left the side of State Highway 1 “looking like a canal”?

Now Turei is trying to emotionally use a single weather event to criticise the Government and promote Green policy on climate change.

Yes, parts of the city were swamped – large parts of the city used to be swamp and have always been at risk of heavy rain accumulation.

“24 hours by 2 months’ worth of rain” is overstating things. On Wednesday there was 150-170 mm of rain. While it’s common for Dunedin to get 40-80 mm of rain in a month it’s not uncommon to get much more. For example:

  • April 2014 – 144.8 mm
  • June 2013 – 195.2 mm
  • May 2013 – 141.8 mm

So only two years ago there was 337 mm in two months.

  • May 2010 – 207 mm
  • June 2009 – 158.4 mm
  • May 2009 – 163 mm
  • June 2002 – 137.4 mm
  • May 2002 – 205.4 mm

So it’s quite common to get heavy rainfall at this time of year. In a single month there was more rain than there was on Wednesday.

  • January 2002 – 251 mm

2002 was a much wetter year than this year has been so far.

  • October 2001 – 164 mm

Source: University of Otago Weather Station

So while this week there was an abnormal amount of rain in a day the total over a month. Including this week’s downpour Metservice shows that rainfall in Dunedin over the last 31 days is just over 200 mm, that’s much higher than usual but not uncommon.

Turei’s last question:

Metiria Turei : Is the Minister not confirming by his dismissive attitude towards the science of climate change that someone is paying the cost of his doing nothing on this issue, and that this week that just happens to be the people of Dunedin?

The present and past Governments haven’t done nothing. They have done far less than the Greens want them to do. But the reality is that even if we eliminated all our emissions, wiped out all emitting animals from the country and reforested the whole country it is likely to have a negligible effect on the world climate.

New Zealand reducing emissions is necessary but in the whole scheme of things it would be little more than a token change, and not weather changing.

As part of the international community New Zealand needs to do something, and should do more than at present.

But Greens have a major problem – if they overstate weather events, if they link single local weather events to world wide climate and if they try to shame other parties into adopting their climate targets then they are likely to find it difficult to get co-operation.

Their over the top claims are more likely to repel rather than attract support for their ideals. Like this One News report:

Climate change and Government’s ‘inaction’ to blame for Dunedin’s 100-year-flood, say Greens

One News have chosen that headline on a rolling blog on the rain in Dunedin that covers many topics.

The Dunedin flood is a result of climate change and the Government’s “inaction” on the issue, the Green Party says.

“The flooding in Dunedin highlights that the National Government needs to stop being the problem and start being part of the solution on climate change,” Green Party local government spokesperson Eugenie Sage said.

“Since National came to power in 2008, New Zealand’s net emissions have increased by 13 percent; the scientific consensus is that increasing emissions will cause more extreme weather events.”

Ms Sage said the Government should aim for an emission target reduction of 40% below 1990 levels by 2030.”Last month it was Wellington. Yesterday it was Dunedin. What region will suffer next from a lack of strong, cross-party leadership on the climate?”

“Strong, cross-party leadership on the climate” – Green-speak for ‘do what we want’ – would have had no effect on flooding in different parts of the country.

At a recent climate change consultatin meeting in Dunedin two Dunedin councillors spoke:

Dunedin City councillor Aaron Hawkins also stood up to speak, his voice cracking.

”I want to acknowledge the anger that’s felt by my generation and people younger … that the question of even having children is such a moral and ethical dilemma.”

Hawkins is not speaking for “my generation and people younger”, he’s speaking for himself and like-minded Greens, a minority.

Cr Jinty MacTavish said the target of a 40% emissions reduction by 2030 many people in the room were calling for – and which was criticised as being inadequate by Prof Bob Lloyd earlier in the night – was a ”compromise”.

So claims for a 40% reduction are seen as a minimum by some.

And their claims are not universally supported. The ODT reports:

Don’t blame climate change for city deluge, weather experts say

The flooding in Dunedin on Wednesday was not caused by climate change, a University of Otago climatologist says.

”I think this is just a weather event,” Dr Nicolas Cullen, of the department of geography, said.

The Green Party and Dunedin Mayor Dave Cull have been quick to link the downpour to climate change.

Dr Cullen cited a 1929 downpour of 220mm within 24 hours, and estimated Wednesday was a one-in-30-year event.

”This particular event is more related just to the weather patterns that developed over the period which allowed that frontal system to really hit Dunedin quite hard.”

”You tell me. It’s wrong,” Dr Cullen said when asked why it was called a 100-year event by the Dunedin City Council.

”I wouldn’t put this in the climate change basket too quickly.”

If the same rainfall happened every month for a year ”then we can start talking about climate change”.

The flood did, however, demonstrate the city’s potential vulnerability to sea level rise, he said.

So a climatologist disputes the claims of the Dunedin City Council politicians and the Green party.

Dunedin hydrologist Dave Stewart said his initial estimate of Wednesday’s flood was a one in 30-to-50 year event.

He had not had time to analyse the data, but rainfall at various sites ranged from 140mm to 180mm.

Mr Stewart was scathing about the DCC’s 100-year claim, saying he did not know how it arrived at the estimate.

He also dismissed the idea the event was linked with climate change.

And a hydrologist disputes the claims of the Dunedin City Council politicians and the Green party.

This highlights a major problem with climate change – exaggerations and unsupportable claims don’t help the Green case of action on reducing emissions. They make it easier to dismiss them as a bunch of extremist nutters.