record in medieval times, two periods of extremely dry climate in at least, the california and nevada region - fit occurred today would totally reset the way we all sort of think about,hydrology, i think. [inaudible] no. your not listening to what the models are telling us. they are telling us there still is the range of natural variability in precipitation eventhough temperature is changing remarkably. evidently that did not get through. but that's what happens. the characterization of precipitation is not unlike today. not rain verses snow, but the total water volume is still looking a lot like the modern climate. >> let me take a crack at this. it's a great question. its the barrier that a lot of water managers face. on the,pa leo climate, side the the past will help me deal with floods and droughts properly deal with them. if we had a better since of this from tree rings in the 1920s we would probably make different assumptions on the colorado rivers. maybe we would not but it was information we did not have about climate that would have changed potentially a decision that water manager'

we know that in the desert in the united states -- arizona, nevada, throughout that region -- the americansonducted many atmospheric tests without telling anyone. there were damages, but they were not destructive. i remember once when khrushchev exploded a 20-megaton bomb, which is 100 times more destructive than the bomb over hiroshima and nagasaki. it was launched into the atmosphere, and there were radioactive emissions over many areas but how many of those kinds of tests have taken place? i do not know whether there would be the hope for survival. when i spoke with economists' from the center for the global economy, they were asking, "what can be done, given a situation like that?" a very challenging d question. one of my colleagues said what you think of this scenario, and it seemed like a science-fiction scenario. what if everything were destroyed? what if the latin american countries were spared this? if you are in a situation like that as an economist, a scientist, what would you recommend kgiven this kind of scenario? that was a question i posed to economists. i reached this conclu

we know that in the desert in the united states, in arizona, nevada, throughout that region the americansc tests without telling anyone, and that there were damages but they weren't destructive. i remember once when cruise chef exploded a 20 mega ton bomb, which is 100 times more destructive than the bomes over japan and it was launched into the atmosphere and there were radio active emissions over many areas. but how many of those kinds of tests have taken place? i don't know. i don't know whether there would be the hope for survival. when i spoke with economists for the center for the global economy, they were asking what can be done given a situation like that? a very challenging situation. because if this wasn't discussed and all of a sudden one of my colleagues said, what do you think of this scenario? and it seemed like a science fiction scenario. what if everything were destroyed? but what if the latin american countries were spared this? if you're in a situation like that as a economist, as a scientists, what would you recommend given this kind of scenario? that was the question i

nevada are among those attending the 14th annual tahoe summit. the focus this year is on developing new ways to protect lake tahoe and its surrounding forest while trying to revive the region'stime for us to talk about our local weather. it seemed to be a little nicer in the city today. >> yeah. i think today is probably one of the nicest days of the month. get ready for the cooling trend. once again, the five-day forecast, especially by the weekend. tomorrow minor changes. the maps i can show you this. mostly clear skies over a good portion of the bay area. the fog bank to the west and already a few patches approaching right around point reyes and the cloud deck on the increase overnight. as far as a look outside right now, we can show you this looking towards san francisco bay and a few patches of fog already doing their thing and developing. and temperatures right now at least right around the bay mainly in the upper 50s at 59 degrees. temperatures from today, we warmed up coast side, also for san francisco, but we actually cooled off inland compared to yesterday's readings. warm spot 75 in antioc, 74 in san jose. weather story is this. fog increase overnight. cool for to