I read the snow.co.nz forums quite a bit, and was interested to see a discussion today regarding skiing in the kaimai’s and other areas of the North Island in the past. As part of this discussion one of the forum users posted this image from NIWA showing temperature in NZ over the last 150 years.
Now I am not one to take a chart at face value so I went hunting around the NIWA website to find the source of the data etc and came across this page: http://www.niwa.co.nz/our-science/climate/information-and-resources/clivar/pastclimate
Now the interesting thing about this chart is it is not based on predictions of the past. It is based on actual records as noted here:
Figure 7: Mean annual temperature over New Zealand, from 1853 to 2007 inclusive, based on between 2 (from 1853) and 7 (from 1908) long-term station records. The blue and red bars show annual differences from the 1971 – 2000 average, the solid black line is a smoothed time series, and the dotted line is the linear trend over 1908 to 2007 (0.92°C/100 years).
Further interesting notes are the more recent history.
Points of interest since 1990 include the cool period in 1992-93 associated with the injection of small particles high into the atmosphere by the eruption of Mount Pinatubo, and the high temperature in 1998 (the warmest year for New Zealand since measurements began). The 1998 warming was apparent in the Tasman Sea to considerable depth (Sutton et al., 2005; Bowen et al., 2006) and happened to coincide with the end of an El Niño event when New Zealand temperatures are usually below normal.
This whole data set is interesting for a number of reasons. The first is that is shows the increase in air temp in NZ over the last one hundred and fifty years as measured – this is important because almost all other charts that you see are based on predicted temp. The second is that it shows quite interesting the end of the little ice age in 1850 and the subsequent heating of the earth.
Now how this relates to global warming is even more interesting. And this is where this chart comes in:
This is the average temperature of the world over the last 150 years again based on actual data (thanks wiki: http://commons.wikimedia.org/wiki/File:Temp-sunspot-co2.svg)
If there was ever a time to sign on to lower C02 levels then now must be it. Visit http://www.signon.org.nz and sign on. Do it.
