1 00:00:01,920 --> 00:00:06,400 Speaker 1: Welcome to brain Stuff production of I Heart Radio. Hey 2 00:00:06,440 --> 00:00:10,880 Speaker 1: brain Stuff, Lauren Vogel Bomb here. If weather is your mood, 3 00:00:11,080 --> 00:00:15,120 Speaker 1: then climate is your personality. That's an analogy some scientists 4 00:00:15,240 --> 00:00:18,000 Speaker 1: used to help explain the difference between these two words 5 00:00:18,040 --> 00:00:22,000 Speaker 1: that people sometimes get mixed up. In other words, whether 6 00:00:22,160 --> 00:00:24,919 Speaker 1: exists in the short term, it's the state of the 7 00:00:24,960 --> 00:00:28,160 Speaker 1: atmosphere in a specific area during a limited period of 8 00:00:28,160 --> 00:00:32,599 Speaker 1: time I think minutes, hours, days, or weeks. Climate, meanwhile, 9 00:00:32,680 --> 00:00:37,360 Speaker 1: describes long term average trends in weather. And if you're 10 00:00:37,400 --> 00:00:41,400 Speaker 1: interested in the ladder, you'd better know geography. Our global 11 00:00:41,440 --> 00:00:45,040 Speaker 1: climate is made up of many smaller regional climates. Break 12 00:00:45,080 --> 00:00:47,960 Speaker 1: those down and you'll find local variations at just about 13 00:00:48,000 --> 00:00:52,920 Speaker 1: every conceivable scale. And that brings us to micro climates, 14 00:00:53,080 --> 00:00:58,040 Speaker 1: an amazing subject with broad applications for farming, conservation, wildlife management, 15 00:00:58,160 --> 00:01:02,800 Speaker 1: and city planning. The climates are a bit like woven tapestries. 16 00:01:03,320 --> 00:01:06,360 Speaker 1: The big picture is important, no question, but so are 17 00:01:06,400 --> 00:01:10,399 Speaker 1: all the seemingly minor details found inside the larger whole. 18 00:01:11,800 --> 00:01:15,400 Speaker 1: We spoke via email with tomaso Uker, an environmental scientist 19 00:01:15,480 --> 00:01:18,240 Speaker 1: at the University of Bristol. He said he would define 20 00:01:18,240 --> 00:01:23,960 Speaker 1: the term microclimate as quote the suite of climactic conditions temperature, rainfall, humidity, 21 00:01:24,000 --> 00:01:28,480 Speaker 1: solar radiation measured in localized areas, typically near the ground, 22 00:01:28,600 --> 00:01:32,920 Speaker 1: and at spatial scales that are directly relevant to ecological processes. 23 00:01:34,319 --> 00:01:36,520 Speaker 1: We'll talk about that last bit in a minute, but 24 00:01:36,800 --> 00:01:41,200 Speaker 1: first there's another criteria to discuss. According to some researchers, 25 00:01:41,200 --> 00:01:45,280 Speaker 1: a microclimate by definition must differ from the larger area 26 00:01:45,440 --> 00:01:49,800 Speaker 1: that surrounds it. Forests provide us with some great examples. 27 00:01:50,360 --> 00:01:53,640 Speaker 1: We also spoke via email with University of Montana ecologist 28 00:01:53,680 --> 00:01:57,360 Speaker 1: Solomon Debrowski. He said the climate near the ground in 29 00:01:57,360 --> 00:02:00,520 Speaker 1: a tropical rainforest is dramatically different from the climate in 30 00:02:00,520 --> 00:02:03,160 Speaker 1: the canopy fifty meters or about a hundred and sixty 31 00:02:03,160 --> 00:02:07,520 Speaker 1: feet above. This vertical gradient, among other factors, allows for 32 00:02:07,560 --> 00:02:13,240 Speaker 1: the staggering biodiversity we see in the tropics. Likewise, scientists 33 00:02:13,280 --> 00:02:17,640 Speaker 1: observed that partial solar eclipse caused the air temperature of 34 00:02:17,680 --> 00:02:21,240 Speaker 1: an Eastern European meadow to change more dramatically than it 35 00:02:21,280 --> 00:02:25,320 Speaker 1: did in a nearby forest. That's because trees provide not 36 00:02:25,400 --> 00:02:30,200 Speaker 1: only shade, but their leaves also reflect solar radiation. At 37 00:02:30,200 --> 00:02:34,760 Speaker 1: the same time, forests tend to reduce wind speeds, and 38 00:02:34,840 --> 00:02:38,120 Speaker 1: all of those factors add up. Twenty nineteen review of 39 00:02:38,200 --> 00:02:42,120 Speaker 1: ninety eight wooded places spread out across five continents found 40 00:02:42,200 --> 00:02:45,679 Speaker 1: that forests are about four degrees Celsie's cooler on average 41 00:02:45,720 --> 00:02:48,600 Speaker 1: than the areas outside of them. That's around seven degrees 42 00:02:48,600 --> 00:02:53,079 Speaker 1: cooler in fahrenheit. Now, if you hate the cold, don't worry. 43 00:02:53,520 --> 00:02:56,680 Speaker 1: There's a cozy exception to the rule. According to that 44 00:02:56,720 --> 00:02:59,880 Speaker 1: same study, forests are usually one degree celsius or a 45 00:03:00,000 --> 00:03:03,519 Speaker 1: at one point eight degrees fahrenheit warmer than the external 46 00:03:03,600 --> 00:03:09,960 Speaker 1: environment during wintertime, which is pretty cool. So when does 47 00:03:09,960 --> 00:03:14,160 Speaker 1: a microclimate stop being well micro? In other words, is 48 00:03:14,200 --> 00:03:16,720 Speaker 1: there a maximum size we should be aware of when 49 00:03:16,760 --> 00:03:20,800 Speaker 1: discussing them. It depends on who you ask, the uker said. 50 00:03:21,200 --> 00:03:25,120 Speaker 1: In terms of horizontal scale, some have defined microclimate as 51 00:03:25,200 --> 00:03:27,720 Speaker 1: anything that's less than a hundred meters or about three 52 00:03:27,800 --> 00:03:33,040 Speaker 1: hundred feet in range. I'm personally less prescriptive about this. Instead, 53 00:03:33,280 --> 00:03:36,280 Speaker 1: he says, the scales we consider microclimates at should be 54 00:03:36,320 --> 00:03:40,240 Speaker 1: determined by the questions we're trying to answer. Quote, if 55 00:03:40,280 --> 00:03:43,040 Speaker 1: I want to know how temperature affects the photosynthesis of 56 00:03:43,040 --> 00:03:46,440 Speaker 1: a leaf, I should be measuring temperature at centimeter scale. 57 00:03:46,920 --> 00:03:49,000 Speaker 1: If I want to know if and how temperature affects 58 00:03:49,000 --> 00:03:52,520 Speaker 1: the habitat preference of a large mobile mammal, it's probably 59 00:03:52,560 --> 00:03:56,040 Speaker 1: more relevant to capture temperature variation across tens to hundreds 60 00:03:56,040 --> 00:04:01,400 Speaker 1: of meters. But yes, solitary plants have the power to 61 00:04:01,480 --> 00:04:06,520 Speaker 1: generate itty bitty microclimates. Just ask Peter Blanken, a geography 62 00:04:06,520 --> 00:04:09,320 Speaker 1: professor at the University of Colorado, Boulder and the co 63 00:04:09,440 --> 00:04:13,680 Speaker 1: author of a book called Microclimate and Local Climate. He 64 00:04:13,760 --> 00:04:17,119 Speaker 1: said via email, a single stock of corn can create 65 00:04:17,160 --> 00:04:20,120 Speaker 1: its own microclimate through the shading and changes in soil 66 00:04:20,160 --> 00:04:23,159 Speaker 1: properties in the immediate vicinity of the stock. For a 67 00:04:23,200 --> 00:04:26,239 Speaker 1: field of corn, the microclimate created would be much larger, 68 00:04:26,279 --> 00:04:31,240 Speaker 1: extending over the entire field. Many organisms eke out a 69 00:04:31,279 --> 00:04:34,440 Speaker 1: living in some of the dinkiest microclimates you can imagine. 70 00:04:34,920 --> 00:04:39,200 Speaker 1: Take aphids, spider mites, and leaf minor insects. All those 71 00:04:39,279 --> 00:04:41,840 Speaker 1: critters are dwarfed by the plant leaves they feed on, 72 00:04:42,320 --> 00:04:46,680 Speaker 1: and every leaf comes with its own microclimate. Observations show 73 00:04:46,720 --> 00:04:50,120 Speaker 1: that aphids seek out cooler leaves, while those other invertebrates 74 00:04:50,120 --> 00:04:53,960 Speaker 1: prefer warmer ones. Because none of these animals can generate 75 00:04:53,960 --> 00:04:57,240 Speaker 1: their own body heat, leaf microclimates have a critical effect 76 00:04:57,279 --> 00:05:01,760 Speaker 1: on their well being. It no secret that our planet 77 00:05:01,800 --> 00:05:04,320 Speaker 1: is going through some rough times. At the macro level, 78 00:05:04,880 --> 00:05:07,600 Speaker 1: the global temperature is climbing. Nine out of the ten 79 00:05:07,720 --> 00:05:10,479 Speaker 1: hottest years on record have occurred since two thousand five, 80 00:05:11,240 --> 00:05:14,760 Speaker 1: and by one reason estimate, roughly one million species around 81 00:05:14,760 --> 00:05:18,600 Speaker 1: the world are facing extinction due to human activities. The 82 00:05:18,760 --> 00:05:21,800 Speaker 1: uker said on one of the big questions that ecologists 83 00:05:21,800 --> 00:05:24,560 Speaker 1: and environmental scientists are trying to answer right now is 84 00:05:24,680 --> 00:05:28,679 Speaker 1: how will individual species and whole ecosystems respond to rapid 85 00:05:28,720 --> 00:05:33,360 Speaker 1: climate change and habitat loss. To me, microclimates are key 86 00:05:33,400 --> 00:05:36,920 Speaker 1: component of this research. If we don't measure and understand 87 00:05:37,000 --> 00:05:40,560 Speaker 1: climate at the appropriate scale, then predicting how things will 88 00:05:40,640 --> 00:05:45,080 Speaker 1: change in the future becomes a lot harder. Developers have 89 00:05:45,279 --> 00:05:48,359 Speaker 1: long understood the impact that small scale climates have on 90 00:05:48,400 --> 00:05:52,000 Speaker 1: our daily lives. Urban heat island is a term for 91 00:05:52,120 --> 00:05:56,440 Speaker 1: cities that have higher temperatures than neighboring rural areas. Plants 92 00:05:56,480 --> 00:05:59,960 Speaker 1: release vapors that can moderate local climates, but in city 93 00:06:00,000 --> 00:06:03,960 Speaker 1: these natural greenery is often scarce, and to make matters worse, 94 00:06:04,200 --> 00:06:06,839 Speaker 1: plenty of our roads and buildings are made of materials 95 00:06:06,839 --> 00:06:10,200 Speaker 1: that absorb or re emit heat from the sun, and 96 00:06:10,520 --> 00:06:15,160 Speaker 1: vehicle emissions don't exactly help the situation. Still, it's not 97 00:06:15,200 --> 00:06:19,960 Speaker 1: like Boston or Beijing are thermal monoliths. Sometimes the documented 98 00:06:19,960 --> 00:06:22,800 Speaker 1: temperatures within a single city vary by fifteen to twenty 99 00:06:22,839 --> 00:06:27,279 Speaker 1: degrees fahrenheit that's eight to eleven degrees celsius. That's where 100 00:06:27,320 --> 00:06:30,279 Speaker 1: metro parks and city trees come in. They have good 101 00:06:30,279 --> 00:06:35,400 Speaker 1: cooling effects on nearby neighborhoods, Blanket said. Several cities around 102 00:06:35,400 --> 00:06:38,640 Speaker 1: the world have developed programs to increase urban green spaces. 103 00:06:39,120 --> 00:06:42,120 Speaker 1: Tree planting programs and green roof programs have been shown 104 00:06:42,160 --> 00:06:46,640 Speaker 1: to lower surface temperatures, decrease air pollution, and decrease surface 105 00:06:46,640 --> 00:06:55,400 Speaker 1: water runoff or urban flash flooding in urban areas. Today's 106 00:06:55,400 --> 00:06:58,119 Speaker 1: episode was written by Mark Mancini and produced by Tyler Klang. 107 00:06:58,600 --> 00:07:00,479 Speaker 1: Or more in this and lots of other cool topics, 108 00:07:00,560 --> 00:07:02,960 Speaker 1: visit how stuff works dot com. Brain Stuff is a 109 00:07:02,960 --> 00:07:05,279 Speaker 1: production of my heart Radio. Or more podcasts in my 110 00:07:05,320 --> 00:07:07,960 Speaker 1: heart Radio, visit the I heart Radio app, Apple Podcasts, 111 00:07:08,040 --> 00:07:09,800 Speaker 1: or wherever you listen to your favorite shows.