Speaker 1: Welcome to brain Stuff from How Stuff Works, Pay brain
Speaker 1: Stuff Lauren Vogelbaum. Here. You might remember when in Republican
Speaker 1: Senator James Inhoff of Oklahoma set out to refute the
Speaker 1: quote hysteria over global warming by tossing a snowball around
Speaker 1: inside the US capital. The obvious implication was, how could
Speaker 1: the climate be changing that radically from humans burning fossil
Speaker 1: fuels and pumping greenhouse gases into the atmosphere, since we
Speaker 1: still have snowfall and chilly temperatures on a winter day.
Speaker 1: But even if you're not a U. S. Senator from
Speaker 1: an oil producing state, you might be wondering how it
Speaker 1: is that scientists can predict climate trends over many years
Speaker 1: but can't predict what the weather will be three weeks
Speaker 1: from today. The reason is that weather and climate are
Speaker 1: two very different things. Basically, whether it is what happens
Speaker 1: today or tomorrow or this week, it's the day to
Speaker 1: day variations. Climate, meanwhile, happens over many years. It's the
Speaker 1: combined long term average of weather events. Scientists look at
Speaker 1: climate in terms of fixed thirty year periods. Right now,
Speaker 1: for example, scientists are comparing the daily temperature to the
Speaker 1: period that started in nineteen eighty one and ended in one.
Speaker 1: They'll shift forward ten years and start comparing temperatures to
Speaker 1: the period between nine and twenty and so on. Scientists
Speaker 1: rely on thirty year periods because it's an amount of
Speaker 1: time that's long enough to produce meaningful comparisons, but just
Speaker 1: short enough that any changes that occur will be subtle
Speaker 1: without being imperceptible. Twenty years might not show enough change,
Speaker 1: and fifty years might be too drastic. To make sense
Speaker 1: of those, thirty year periods help us put the weather
Speaker 1: on a particular day in the right context. Comparing the
Speaker 1: temperature on December to the same day a hundred years
Speaker 1: ago wouldn't provide that much useful information because the climate
Speaker 1: was too different then, but comparing it to the average
Speaker 1: of the temperature readings for every December five between nine
Speaker 1: and twenty ten, when the climate conditions were pretty much constant,
Speaker 1: makes it possible to say whether a given to number
Speaker 1: five is an unusually cold or warm day. We spoke
Speaker 1: with Jonathan Martin, a professor of atmospheric and oceanic studies
Speaker 1: at the University of Wisconsin Madison. He explained or trying
Speaker 1: to compare apples to apples when it comes to prediction.
Speaker 1: Whether in climate are also very different. Weather forecasting, Martin explains,
Speaker 1: is based upon observation of conditions that are already occurring
Speaker 1: in real time in the atmosphere. Because those conditions only
Speaker 1: exist for a short time, whether it can be reliably
Speaker 1: forecast only over relatively short periods of ten to fourteen
Speaker 1: days at most, though Martin said that's theoretical, My confidence
Speaker 1: ends at day eight. Envisioning climate, in contrast, is much
Speaker 1: more low resolution. Scientists are trying to project what the
Speaker 1: trend will be over a long period, not what the
Speaker 1: weather will be like on a specific day fifty or
Speaker 1: a hundred years from now. That involves gathering and crunching
Speaker 1: huge amounts of data in powerful computers and doing modeling.
Speaker 1: We also spoke with Jeffrey S. Duke's director of the
Speaker 1: Climate Change Research Center at Purdue University. He said, in
Speaker 1: one sense, climate does not affect weather. It's a description
Speaker 1: of the weather over a long period. You could turn
Speaker 1: that around and say that climate provides you with information
Speaker 1: about how likely you are to get a given type
Speaker 1: of weather at a given time of year. But historically
Speaker 1: the climate has been determined by the weather over long periods.
Speaker 1: He continued In another sense, though, climate for a given
Speaker 1: location is determined by a bunch of factors, such as
Speaker 1: the latitude and position on the planet, which affects how
Speaker 1: it is influenced by the circulation of the atmosphere and oceans,
Speaker 1: and the daytime heating of continents. Climate is also influenced
Speaker 1: by the composition of the atmosphere, the transport of water
Speaker 1: from soil to air by plants, and other factors. On
Speaker 1: a given day, the sum of all these influences determines
Speaker 1: the weather, but as some of these larger scale factors
Speaker 1: change over time, they will drag the weather and the
Speaker 1: climate along with them. In recent years, some of the
Speaker 1: sharp distinction between weather and climate has blurred slightly as
Speaker 1: scientists have used increasingly phisticated models and accumulated knowledge in
Speaker 1: an effort to figure out the extent to which some
Speaker 1: specific weather events, say a hurricane, a heat wave, or
Speaker 1: a monster snowstorm, is actually a function of climate change
Speaker 1: driven by humans releasing greenhouse emissions into the atmosphere. By
Speaker 1: running thousands of computer simulations, they can conduct what if experiments,
Speaker 1: seeing how the atmosphere would behave if you removed one
Speaker 1: factor or another. Although such analysis is still a work
Speaker 1: in progress, Martin thinks that eventually it will be possible
Speaker 1: to determine the extent to which specific weather events are
Speaker 1: influenced by climate change. Some of that research is already
Speaker 1: bearing results. The National Oceanic and Atmospheric Administration presented a
Speaker 1: paper in December in which they concluded that three extreme
Speaker 1: weather events in that year's record global heat, extreme heat
Speaker 1: over Asia, and unusually warm waters in the Bearing Sea
Speaker 1: would not have been possible without human caused climate change.
Speaker 1: Today's episode was written by Patrick J. Keiger and produced
Speaker 1: by Tyler Clang. For more on this and lots of
Speaker 1: other stormy topics, visit our home planet, how stuff Works
Speaker 1: dot com. M