Emissions Don’t Raise NZ Temperatures

The New Zealand
Climate Science Coalition

5 August 2011 FOR IMMEDIATE RELEASE

Emissions Don’t Raise NZ Temperatures

No correlation here between CO2 and climate

New Zealand temperatures were flat during the 20th century and have been declining during the 21st century.

This claim is made in two papers released today by the New Zealand Climate Science Coalition.

“For almost 20 years, successive New Zealand Governments have been officially advised that domestic temperatures had risen sharply over the past 100 years, reflecting increases in atmospheric concentrations of carbon dioxide” said Barry Brill, chairman of the Coalition. “We now show that this advice was plainly wrong.”

NIWA’s advice to the Government (based on reports of the UN Intergovernmental Panel on Climate Change – IPCC) is that the 20th century global warming trend of 0.7°C exceeds the bounds of ‘natural variability’ and that most of the excess is probably caused by the increase in human-caused emissions of CO2 and other greenhouse gases.

Since about 1750, the atmospheric concentration of CO2 has increased from 280ppm to almost 400ppm, with almost half of this increase occurring in the last 30 years.

The New Zealand climate data offers no support at all for the claim that CO2 causes warming:

• There has been no acceleration in warming trends during the past 60 years, despite increasing global GHGs.

• The 5-station 30-year trends show a substantial deceleration between the peak period in 1949-78 and 1979-2008.

• The 0.2°C/decade trend predicted by IPCC climate models has not occurred, either globally or in New Zealand.

• Decades with the most New Zealand warming are (1) 1930s (2) 1950s, while the greatest cooling occurred in (1) 1940s, (2) 1970s and (3) 2000s.

NIWA has relied upon 2000-10 being “the warmest decade on record”. But climate change concerns relate to temperature changes (ie warming), not to absolute temperature levels (ie warmth).
Table 5 shows New Zealand’s historical average temperatures since the instrumental record began, divided by decade. The first group is coloured according to mean warmth, with the warmest in red and the coolest in blue. The second group is coloured according to warming trend.
Note that there has been no really significant trend since the 1950s, and that there has been a cooling trend since the turn of the century.
All New Zealand temperature trends have been modest, short-lived and unpredictable. They change constantly in both sign and amplitude, displaying no discernible pattern. Clearly, they are not responding to any linear or progressive external forcing (See Table 5 from the NZCSC Report)

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