15 February 2011

Nick Smith mistakes gross and net GHG emissions

Still on the topic of Nick Smith not being able to tell the difference between gross greenhouse gas emissions and net greenhouse gas emissions (after subtracting forest carbon removals).

It needed its own chart. Here it is. Nick Smith's press release of 10 February 2011 says net GHG emissions in 1990 are 61 million tonnes - the large blue dot. That is actually the gross GHG emissions. Russel Norman's press release of February 2011 gives the correct 1990 net GHG emissions 29 million tonnes according to the Ministry for the Environment.

Here is the R code.

Year<-c(1990:2007)
gross<-c(61.84,62.02,63.21,62.94,64.10,64.45,66.02,68.87,66.96,68.60,70.58,73.10,73.44,75.99,75.04,77.16,77.59,75.54)
net<-c(30.77,30.49,32.67,32.29,34.21,35.68,37.31,39.00,35.17,36.15,39.30,42.89,45.85,47.57,47.14,53.37,57.88,58.72)
png(file="Smith.png",pointsize = 16,width=600,height=500)
plot(Year,gross,axes="FALSE",type="n",xlim=c(1990,2007),ylim=c(0,82),xlab="Year",ylab="Emissions (Megatonnes)",main="New Zealand's Gross & Net GHG Emissions 1990 to 2007")
axis(1,line=0,at=Year,labels=Year,lwd=1)
axis(2,lwd=1)
points(Year[1],net[1],pch=19, col=3,lwd=8)
text(1990,23,"Norman's \nNet GHG \nemissions",adj=0, col=1)
points(Year[1],61.7,pch=19, col=4,lwd=8)
text(1990,54,"Smith's \nNet GHG \nemissions",adj=0, col=1)
points(Year,net, type="l",col=3,lwd=2)
points(Year,gross,type="l", col=4,lwd=2)
legend(1996, 25,bty = "n", c("MfE Gross GHG emissions","MfE Net GHG emissions"),lty = c(1,1), pch=c(NA,NA),lwd=c(2,2), col = c(4,3))
mtext(side=1,line=-1.5,cex=0.8,"Source: MfE 2010 New Zealand’s Greenhouse Gas Inventory 1990–2008")
box()
dev.off()

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