climate scientist michael mann speaks with correspondent miles benson. coming up on "earth focus." >> we will have years like this more often than not. and we've had that for the last 5 years. >> and there just aren't enough sandbags to go around. still not enough sandbags to go around. >> i haven't seen a winter like this in a really long time. or even maybe never. >> we've been seeing some severe weather. expect to see more. it's coming. hurricanes, floods, droughts, raging wildfires, snowstorms, and tornadoes. is this purely nature, or are there manmade, therefore controllable, factors at work? a warmer, moister environment can intensify storms, creating heavier precipitation. and this scientists say is why human activities may account, at least in part, for the rise in extreme weather we're experiencing. >> the debate is settled. climate change is a fact. and when our children's children look us in the eye and ask if we did all we could to leave them a safer, more stable world with new sources of energy, i want us to be able to say yes, we did. [appl

global warming heatstroke is going to be the least of our worries that's because according to michael mann one of the world's leading climate scientists really only have to twenty thirty six twenty two years to prevent the earth's temperature from rising two degrees celsius after that michael mann says global warming will lock in with devastating quantz consequences for every single living thing on this planet serious scientific bodies are even debating whether or not industrial civilization could survive such a drastic temperature increase and the types of crazy weather while version droughts that would come with. other scientists like james hansen have an even gloomier view of how much more warming our planning can take. hansen argues that we need to lower the limit of acceptable warming by hold agreed to one single degree celsius the number we're already eight tenths of the way to at this point there's really only one thing we can do to prevent a total climate catastrophe along the lines of james hansen and michael mann and what they're predicting we need to keep carbon in the ground an

we were just talking with dr michael mann about carbon and you know his idea that we need to at least put a price on carbon president hasn't gone that far but you know carthy has said a thirty percent reduction from two thousand and five levels we've already had a seventy percent reduction. since two thousand use we're after there by twenty thirty. however the fuel fossil fuel industry and their largely i think wholly owned republican party have come out and said this is part of obama's war on the war on coal if coal is killing our planet what's wrong with having a war you know what i also think is interesting it was just you know in two thousand and eight that nancy pelosi and newt gingrich got together for that big television ad spot where they were saying that climate change was this big threat to human civilization and both parties needed to take action against that news yet walk that yeah i don't really know it's really a question for republicans as to what's happened in their party that this has become such a third rail over the past eight years six years when it speaking of pos

we apologize for michael mann.al problems. >>> still ahead after billions of dollars spent and millions of people jailed still no victory on the war on drugs. i'll talk to a top film maker who says the biggest victims are people of color. power plant in the country to combine solar and natural gas at the same location. during the day, we generate as much electricity as we can using solar. at night and when it's cloudy, we use more natural gas. this ensures we can produce clean electricity whenever our customers need it. ♪ ♪ ♪fame, makes a man take things over♪ ♪fame, lets him loose, hard to swallow♪ ♪fame, puts you there where things are hollow♪ the evolution of luxury continues. the next generation 2015 escalade. ♪fame i got more advice than i knew what to do with. what i needed was information i could trust on how to take care of me and my baby. luckily, unitedhealthcare has a simple program that helps moms stay on track with their doctors and get the right care and guidance-before and after the baby is born. sim

and and michael one of the i had a conversation earlier on the radio with dr michael mann and we weretalking about this weird winter we just had with it where and particularly the central and eastern united states all this polar air just slid down on top of us. and you know he was talking about how there's a still a debate in the scientific community about exactly what's going on but. one of the theory. is that that i put forward he said that that's absolute one of the ones being discussed is that there used to be a huge a really significant much larger temperature gradient a difference between the temperature of the arctic and the temperature of these mid-latitudes where we live or there or the the course of the temperate region it go and and because the arctic is warming so much faster particularly because of the i seem to affect it all that that but also because of just that's the nature of it is that temperature gradient is deteriorating the point where there's not a wall of of different pressure different temperature air holding the arctic air up there and so is a slide so so thi

michael don't realise how funny and hilarious he was. >> it raising concerns about media. >> definitely, he tells a story in an entertaining way how news can be mann ip ute lated by -- mann ipualated by journalists. in 2003, as soon as the iraq war was not going, a lot disavowed their positions and completely erase that from time, in light of the people pivotal in gaining support for the war. >> what would you like his legacy to be? >> always telling the truth, and i would like people to remember how he stood up to power and pursued truth no matter what. >> pleasure to have you with us. good luck with the book. nice to have you with us. >>> coming up the late night talk show game is changing. this time the only female host is heading to netflix. will anyone watch. >>> first, the transformation of america by the numbers, that's >> guns... >> there are two to three million guns in a population of only 8 million people. >> ...and gun laws... >> after those laws came in, there have been no more mass shootings... >> how different countries decide... >> their father had a gun... their grandfather had a gun... >> who has the right to bear arms? 5 days: g

question from james mann, who has written several books on the realists and neocons and on the obama administration, and told me he just completed a short biography on george w. bush. >> michael, thanks for this. i have one question you haven't mentioned but i read is in our article, which is immigration. i would be curious to know how it fits in your thinking and article. both -- and maybe it applies equally -- as to low skilled immigration, paradigm central america, and high-skilled paradigm i guess, india. >> i approach this from the view of strategy in general. if you have a rule governed global market with relatively free flows of capital and of labor, then you can have a shrinking population, and you're -- as long as per capita gdp is going up, then your country can get richer and richer. you know, so that japan, say, could shrink. fewer and fewer people every decade but the fewer people would be richer because the productivity growth is going up and they're better off. in a mercantilist world, in a world where some or most powers are treating economics as an instrument of state craft rather than a rule governed zerosome game, then the logic is different because the hig