Keelercurve <- function(
          url="ftp://ftp.cmdl.noaa.gov/ccg/co2/trends/co2_mm_mlo.txt",
          urlbg="http://www.realclimate.org/images/raffinery.jpg") {
  
  require(jpeg)
    if (!file.exists("raffinery.jpg"))
     download.file(urlbg,"raffinery.jpg")
  img <- readJPEG("raffinery.jpg")

  Mauna.Loa <- read.table(url,
                          col.names=c("year","month","yymm","ave","interp",
                                "trend","no.days"))
  #Mauna.Loa[Mauna.Loa<0] <- NA
  co2 <- Mauna.Loa$interp
  yy <- Mauna.Loa$year
#  yy <- as.matrix(Mauna.Loa[,1])
#  yymm <- sort(rep(yy,12) + (rep(1:12,length(yy)) - 0.5)/12)
  yymm <- Mauna.Loa$yymm
  

  dev.new(width=10,height=8)
  par(bty="n",xaxt="n",yaxt="n",mar=rep(0,4),fig=c(0,1,0,1))
  plot(yymm,co2, type='n')
  rasterImage(img, 0.999*min(yymm), 0.99*min(co2),
              1.001*max(yymm), 1.01*max(co2))
  lines(yymm,co2,lwd=11,col="white")
  lines(yymm,co2,lwd=9,col="grey30")
  text(mean(yymm),max(co2),"CO2 concentrations (Mauna Loa)",font=2,cex=1.75)
  text(min(yymm),min(co2),"1958",col="white",pos=4)
  text(max(yymm),min(co2),"1958",col="white",pos=2)
  dev2bitmap("CO2.png",res=150)
}