In a sketch of current and projected effects of climate change, "Scientists fear we've passed tipping point on climate change," (Jan. 27), author Carolyn Lochhead corrupts her own effort to suggest what may be a perilous situation for mankind by including a supposed contrasting view by bioclimatogist Ashley Balantyne. We know from ice core and other data that the past warming events referred to in Balantyne's characterization occurred on geologic, rather than human, time scales. Thus, multi-generational human families of the periods - had they existed - would not have experienced the profound changes that we have observed in a century. Whether or not Balantyne is "gloomy," it's likely he grasps the distinction.