Ignore the values of lat and long (i.e., x and y) in the Bio4 calculation

[susyelo]

https://github.com/KerkhoffLab/climate-velocity/blob/0db4745cbd3f974558ae769a6b5588c6b3616dfe/functions/bioclim.var.r#L23

As it is written the code calculates bio4 based on all the variables in the data frame "temp" which includes the lat and long coordinates. In the following line, we can ignore these values.
clim$bio4 <- (rowSds(as.matrix(temp[,-c(1:2)]), rows=NULL, cols=NULL, na.rm=FALSE))/clim$bio1*100