Rising Sea Levels NZ
February 26th, 2009 | by noel |Rising sea levels are part of our future so we may as well get on with figuring out how to cope with the changes in sea level due to global warming.
Rather than deny it is happening, or hoping it is some kind of conspiracy, or arguing whose fault it is, this post is about estimating when the sea will rise, and to what levels.
Recent research about global warming has come up with these disturbing findings:
1. Global warming is likely to accelerate at a much faster pace and cause more environmental damage than previously predicted.
http://www.abc.net.au/news/stories/2009/02/15/2491942.htm?section=world)
2. Future temperatures will be beyond anything predicted…
In 2001 the United Nations-sponsored Intergovernmental Panel on Climate Change (UN-IPCC) reported that the average temperature is likely to increase by between 1.4 and 5.8 degrees Celsius (2.5 and 10.4 degrees Fahrenheit) by 2100.
By 2007 the UN-IPCC was predicting temperature rises between 1.1C and 6.4C by 2100… but…one of the authors of the report recently admitted that many factors were not taken into account because of political pressure and the 2007 report seriously underestimated the scale of the problem.
http://news.bbc.co.uk/2/hi/science/nature/7890988.stm)
3. New studies are warning of a greenhouse gas time-bomb that could amplify global warming – permafrost in Siberia and Canada releasing huge amounts of methane.
http://www.smh.com.au/environment/global-warming/feedback-could-amplify-climate-change-peril-20090216-891i.html
4. Widespread devastation of plankton, the start of the food chain in Antarctic waters, by 2030.
http://www.news.com.au/couriermail/story/0,23739,24636575-953,00.html
5. Air temperatures on the Greenland ice sheet have increased by about 3.75 degrees Centigrade (7 degrees Fahrenheit) since 1991. Sure it is just one spot on earth, but if the average was a rise of 3.75 degrees every 20 years for all of the planet, then by 2100 temperatures would be 18.75 degrees Centigrade higher than they are now! (Even at a global rate of change of just 9 degrees Centigrade – which is more and more likely, life will cease to exist in many places, and way before 2100.)
6. Then there is the biggie that I find really worrying – the possibility of a massive and catastrophic release of methane from the ocean floor that could wipe out humanity.
http://www.killerinourmidst.com/
My point here – global warming is here to stay for the foreseeable future.
Get over it and start thinking about the solutions rather than being part of the problem so we can figure out how to survive.
So how far and how fast do I think sea levels will rise?
Here is the historical and measured rate of sea level change:
1990 – 2mm
2000 – 4mm
2010 – 8mm
Notice how the rate doubles every ten years.
I am going to stick my neck out here and give you my best estimates:
By 2050
Low – 5m
Expected – 14m
High – 60m
By 2100
Low – 14m
Expected – 60m
High – 100m
All of this within my grandson’s lifetime…
By the way, if you think 100m is ridiculous, check this out:
“…if greenhouse gas emissions carried on as they were, CO2 levels would be high enough to melt the Greenland and Antarctic ice sheets in 100-200 years, making the sea rise about 100m.”
http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10551751
Things to do:
1. See what New Zealand looks like when the sea has risen 14m (expected by 2050), by checking out the Google Flood Map.
http://flood.firetree.net/?ll=-36.9762,175.4791&z=9&m=14)
2. See what New Zealand looks like with a sea level rise of 60m (expected by 2100)
http://www.globalwarmingart.com/sealevel?lat=-40.664&lng=170.706&zoom=6
I have yet to develop a 100m map showing the effect of rising sea levels.
But think about this…
When the the sea level rises to 100m:
- The only current major airport still workable in the North Island is Rotorua.
- The mouth of the Waikato River is at Arapuni
- Tirau is on the sea shore
- Kinleith near Tokoroa is the only major industrial zone in the North Island
- Greatford, about 6km north of Bulls on State Highway 1, is at sea level
- The mouth of the Clutha River is at Roxburgh
- The West Coast Road starts at Aylesbury and ends near Wainihinihi
- Our climate is similar to Northern Australia right now
And if you think we will have problems, check out the rest of the world…
(More to follow on this subject)
Comments appreciated.
Some Effects on NZ of the Sea Level Rising 14m
4 Responses to “Rising Sea Levels NZ”
By cm on Dec 2, 2009 | Reply
Unbelievable. There is no evidence to support a 14m rise by 2100. Even the most dire IPCC numbers are less than 1m and even those seem quite a stretch.
What’s your motivation to try push out alarmism like this?
Do you have scientific training or is this just what you “feel”?
By admin on Dec 2, 2009 | Reply
Hi Cm,
First of all let me say that I hope I am completely wrong about all of this.
That said, my interest was piqued when I read the following article: http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10551751
I thought – this guy is nuts – it cannot be.
Everyone else is saying it will be 1m or less (although I believe in the last day or two we have seen a revision to 1.6m by the IPCC people).
To try and find out what was going on, I looked at all of the published numbers I could find. The IPCC stats were part of this – but the IPCC was very conservative – probably because of the numbers of scientists involved, politics etc, so the art of compromise crept into the estimates. In other words it was a committee decision that tried to please everyone instead of the truth.
Working from memory here, but the stats I saw for the last century were showing that while the overall sea level rise in 100 years was relatively small (2mm from memory) that 25% of the change had taken place in the first 50 years and 75% of the change had taken place in the last 50 years. i.e. the rate of change was speeding up but the way the stats were being presented disguised this – I have no idea whether this was intentional. (Not the point as I see it, but it could be argued that the IPCC were fudging the numbers so they were not too alarmist?)
Anyway, as I kept burrowing into things I saw more and more figures that suggested that the IPCC numbers were way under what was likely i.e. the IPCC stats were not only presented using “averages” which disguised the increasing rate of change but the numbers themselves were way too low based on the latest findings. i.e. the IPCC numbers were seriously understated and this was proved again and again. It was as if the IPCC people were looking in the rear view mirror and did not have the balls to proffer an opinion (I can understand why when we still have people in NZ who say it ain’t happening etc – and if you are a publicly funded scientist, who needs the aggravation, right? I mean you might get fired from NIWA or something!)
Another part of the IPCC problem was that the scientists were not adding all of the sources into the equation. Some would give an estimate that only took account of glaciers, others just Greenland, others just thermal expansion etc – as if they were only interested in one leg of an elephant – whereas I was trying to get the complete picture.
Moving right along… armed with 3 historical data points re sea level, I extrapolated the numbers using various scenarios. I allowed for cumulative effects and for the non-linear mathematics of nature. My numbers ended up more or less agreeing with the numbers mentioned in the NZ Herald article.
Here are the factors:
Rate of change – doubles every 10 years based on 2mm increase e.g.
1990 2mm per annum
2000 4mm per annum
2010 8mm per annum
Maximum is 256mm in 2060 and stays that way.
Then look at the Total rise per period e.g.
1990 20mm in 10 years
2000 40mm in 10 years
2010 80mm in 10 years
Then look at the cumulative rise e.g.
1990 20mm in 10 years
2000 60mm in 10 years
2010 140mm in 10 years
…and you end up with a 15m rise by 2100.
I do have the source of the initial rates of change somewhere but not handy. They are disturbing because they are doubling. But I ran with this number series because by and large that is how life is – e.g. cell growth etc, so let’s allow that to be the rate of change.
The real bugger is that news items over the last few months tend to reinforce the doubling series. And as I mentioned above, the doubling series results in a set of numbers that agree with the NZ Herald article.
But like I say – I hope I am wrong. But so far the jury is out.
By admin on Dec 2, 2009 | Reply
One last thing – I have revised my numbers downwards since January – I now think my minimum scenario is most likely. 3-5m by 2050 and 14-15m by 2100. (God help us if the 100m estimate is correct!)