Unit 9: AP Environmental Science Faculty Lecture with Associate Teaching Professor Julie Ferguson

Summary

In an enlightening lecture by Associate Professor Julie Ferguson from the University of California, Irvine, the intricate links between global climate change and extreme weather were explored. Ferguson detailed how human activities are significantly contributing to changes in greenhouse gas levels, driving rapid climate shifts that amplify extreme weather events. These changes are causing more intense wildfires and hurricanes, with significant economic and social impacts. The lecture stressed the importance of proactive policies and understanding environmental justice to mitigate these impacts effectively. Ferguson also provided a hopeful outlook on collective action and adaptation strategies to combat climate change's adverse effects.

Highlights

• Julie Ferguson from UC Irvine discusses global change focusing on climate change and extreme weather. 🌦️
• Climate change is primarily driven by greenhouse gases, notably CO2 and methane. 🌍
• Human activities like burning fossil fuels and deforestation significantly contribute to climate change. 🔥
• Climate change makes extreme weather events like hurricanes and wildfires more severe. 🌀🔥
• The importance of understanding the difference between weather and climate is emphasized. 🌦️🧐
• Ferguson explores the complex factors causing wildfires to increase in intensity. 🌲🔥
• The economic and social consequences of extreme weather events are profound, emphasizing the need for resilience. 💰🛡️
• Adaptation and proactive policies can mitigate the impact of climate change, promoting environmental justice. ⚖️
• Collective efforts offer hope and strategic opportunities to tackle climate change efficiently. 🤝

Key Takeaways

• Climate change is accelerating due to increased greenhouse gases, mainly from fossil fuel use and deforestation. 🌍
• Extreme weather events like hurricanes and wildfires are becoming more intense and frequent, significantly impacting communities and the economy. 🌀🔥
• Understanding and distinguishing between weather and climate is crucial for analyzing extreme weather events. 🌦️📊
• Adaptation strategies and proactive policies are essential to mitigate climate impacts and ensure environmental justice. 🛡️⚖️
• Collective action against climate change offers opportunities for societal transformation and resilience building. 🤝🌱

Overview

Associate Teaching Professor Julie Ferguson presented a compelling lecture that navigates through the complex relationship between global climate change and extreme weather events. As part of the AP Environmental Science curriculum, Ferguson highlighted the critical role human activities play in accelerating climate change through increased greenhouse gases, primarily from fossil fuel consumption and deforestation. By underscoring how these gases intensify weather phenomena like hurricanes and wildfires, the lecture aimed to instill a clearer understanding among students about the urgency of addressing these issues.

Ferguson's lecture delved into the nuanced discourse distinguishing weather from climate, and how climate change amplifies the severity of natural disasters. While hurricanes' frequency might be undetermined, their intensity and destructive potential are expected to rise due to warmer ocean temperatures. Similarly, wildfires are not only burning longer but also hotter, creating significant threats to both public safety and the environment. These scenarios reveal the dire need for enhanced policy measures and adaptation strategies to cope with these escalating threats.

A positive outlook was shared by Ferguson, emphasizing the importance of collective and informed action to mitigate climate change impacts. By fostering a sense of environmental justice and equitable policy development, society can navigate through these challenges and potentially transform infrastructures, economies, and communities. Encouraging students to look at the broader societal impacts of these environmental changes, Ferguson highlighted that understanding science and policy interplay is paramount to reaping the opportunities borne from climate-resilient innovations.

Chapters

• 00:00 - 01:30: Introduction and Guest Introduction The chapter titled 'Introduction and Guest Introduction' begins with the hostess, Julie Ferguson, from the University of California, Irvine. She expresses her delight in discussing topics related to Unit 9 of the AP Environmental Science class, focusing on global change. Julie highlights that amidst many interesting subjects, she chose to address climate change and extreme weather due to their significant impact.
• 01:30 - 04:00: Climate Change Fundamentals The chapter begins with the speaker acknowledging that climate change impacts everyone, whether directly or indirectly, and emphasizes the societal costs involved. The speaker introduces themselves as a UK native who relocated to California in 2008 to join the Department of Earth Systems Science at the University of California.
• 04:00 - 06:00: Extreme Weather Events and Climate Change The chapter discusses research at California Irvine focused on paleoclimate studies. The researcher employs methods like analyzing tiny plankton shells found in deep-sea sediment cores, the chemical composition of mollusk shells at the beach, and tropical corals to reconstruct past climate changes. These records aid in testing the accuracy of climate models.
• 06:00 - 20:00: Focus on Wildfires The chapter titled 'Focus on Wildfires' involves a discussion on enhancing the reliability of information regarding global change, especially in the context of wildfires. The narrator is engaged in teaching introductory environmental science classes, emphasizing both scientific and socio-economic aspects within the curriculum. These classes are an integral part of degree programs like the BS in Earth Systems Science, which centers on global change science, and the RBA in Environmental Science and Policy, which intertwines environmental science with policy and socio-economic factors.
• 20:00 - 37:00: Focus on Hurricanes The chapter titled 'Focus on Hurricanes' begins with a discussion on the broader subject of the environment, specifically honing in on climate change and its impact on extreme weather events. The chapter emphasizes the consensus among climate scientists regarding the rapid changes in our climate, particularly when compared to historical climate patterns.
• 37:00 - 45:00: Climate Change Mitigation and Adaptation Strategies The chapter titled 'Climate Change Mitigation and Adaptation Strategies' discusses the rapid climate changes occurring due to the increased concentrations of greenhouse gases like carbon dioxide and methane. These gases are identified as primary drivers of the current climate changes, which contrasts with the various natural reasons that have caused climate variation over Earth's history.
• 45:00 - 48:00: Environmental Justice in Disaster Contexts The chapter titled 'Environmental Justice in Disaster Contexts' delves into the impact of human activities on greenhouse gas emissions. It highlights how actions such as burning fossil fuels for transportation and electricity generation, along with deforestation, particularly in tropical forests, contribute significantly to the release of carbon dioxide into the atmosphere. The discussion ties these activities to broader environmental changes, emphasizing the need to address such issues in understanding disaster contexts and promoting environmental justice.
• 48:00 - 49:30: Conclusion and Encouragement for Future Action The chapter discusses the impact of societal decisions on future climate changes, emphasizing the significance of switching to renewable energy and preventing deforestation. These actions are crucial in determining the scale and speed of climate changes in the coming years. The focus is on the link between extreme weather and climate change.

Unit 9: AP Environmental Science Faculty Lecture with Associate Teaching Professor Julie Ferguson Transcription

• 00:00 - 00:30 so hello everyone my name is julie ferguson and i am at the university of california irvine in southern california and i'm delighted to be with you today to talk about a topic related to unit 9 of your ap environmental science class all about global change and this was a challenge for me but there's so many really interesting topics that i could have chosen from and i narrowed it down because i'd like to talk with you today about climate change and extreme weather something that is really going to affect
• 00:30 - 01:00 all of us either personally if you've experienced or might experience an event like this in the future or just more broadly as a society because we're going to have to deal with the costs of these events so firstly before i get started i wanted to share a little bit of information about me so as you can tell from my accent i am originally from the uk but i moved to california in 2008 to work at the department of earth systems science at the university of
• 01:00 - 01:30 california irvine and this was after my phd and i came here to do more research on paleoclimate because my research is all about developing records of past climate change and i do that by using uh tiny plankton shells that we find in deep sea sediment cores or by using the chemical composition of things like mollusk shells that you'd find at the beach or also tropical corals as well and we use that information to test how good our climate models are
• 01:30 - 02:00 and sort of increase our reliability that they're giving us good information now i tend to do more teaching and so i teach a lot of introductory environmental science classes uh including to our majors in our bs in earth systems science which is all about the science of global change and what we can do and then also our new degree rba in environmental science and policy which covers both the environmental science but also the social economics the policy
• 02:00 - 02:30 the law all about the environment so we're going to be talking about climate change today but just one small aspect which is how it affects extreme weather and so before i talk about that more specifically i wanted to make sure that you understand that there are certain things about climate change that all of our climate scientists agree on the first is that our climate is changing and changing really quickly especially compared to the climate that
• 02:30 - 03:00 we've had over the past 10 000 years or more and really the reason that we're seeing that rapid change is because we have increasing amounts of greenhouse gases such as carbon dioxide and methane in our atmosphere we know that there are lots of reasons why our climate can change on different time scales over earth history but really we know pretty certainly that it's the greenhouse gases that are causing the change we see today and so why is it we see these increasing
• 03:00 - 03:30 greenhouse gases well you've probably learned this in your ap environmental science class that human activities for example burning fossil fuels for transportation or to generate electricity is releasing carbon dioxide to the atmosphere but also deforestation especially the the deforestation happening in our tropical forests is also returning carbon back to the atmosphere as well and so these are the activities that are really responsible for the change and what that means is that going
• 03:30 - 04:00 forward if we look at the future climate changes that are coming really how much change we're going to see depends on what we as a society decide to do do we switch to renewable energy do we prevent deforestation that is going to have a really big impact on the scale of the change and the speed of the change that we see in the coming decades and centuries so today i'm going to talk to you about extreme weather and how it links to climate
• 04:00 - 04:30 and so i wanted to make sure that we're really certain about the difference between weather and climate because journalists get this wrong all the time there's lots of news headlines about this or this heat wave or this drought being climate change and it's actually a bit more complicated than that so when i talk about weather i mean the condition of the atmosphere over a short period of time it might be a few days or so it might be just an hour so an example of this might be a hurricane for example
• 04:30 - 05:00 or a heat wave that is a weather event when we talk about climate we're instead talking about long-term sort of 30-year averages of our climate and so for example we have warmer conditions over the last 30 years than the preceding 30 years that would be about climate change and this makes it difficult when we think about extreme weather because we can't point at any one hurricane or any one wildfire or
• 05:00 - 05:30 heat wave and say that that event was caused by climate change it may have happened anyway but what we can say with increasing levels of certainty is that climate change makes these extreme weather events more intense so it makes them more extreme that hurricane is more strong that heat wave is hotter than it was before and in some cases it also may make them more frequent and so we're going to look at a couple of examples today and think about why it
• 05:30 - 06:00 is that climate change may make that happen so why should you care about this because these events are incredibly damaging to the people that experience them but also incredibly damaging to our economy as a country as well so this is a great diagram that we've taken from the national oceanographic and atmospheric administration website and it shows all of the weather events in 2020 that cost more than one billion dollars
• 06:00 - 06:30 in terms of the damage and you can see that there's really interesting patterns in terms of the type of extreme event that you get in different places so over on the west coast the big extreme events that we saw in 2020 were related to wildfire and many of you who live in this region may have experienced the effects of that if we come towards the middle of the country we have a drought in the summer months there and then later on in the year we also saw more flooding and these extreme
• 06:30 - 07:00 thunderstorm events also we had tornadoes and then the other event that we're going to talk about today is mainly experienced by people in the south west of the us but also sometimes hawaii and that is hurricanes you can see that there were quite a large number of hurricanes that made landfall that hit the us mainland last year and so we want to think about how is climate change going to affect these events and that helps us come up with a plan to
• 07:00 - 07:30 actually do something about it and protect people from the harm that that may cause so to begin with we're going to start off on the west coast i'm going to take an example from the west coast in wildfires and then we're going to look at the east coast and think about hurricanes so first of all it's important to mention that wildfires are a natural part of many ecosystems especially in the western us and they can actually have a lot of beneficial effects in terms of recycling nutrients
• 07:30 - 08:00 a lot of our ecosystems depend on say fire clearing the forest floor allowing seeds and new trees to to grow but wildfires can also cause death it can damage human property as well as causing quite widespread uh harmful air pollution and it can cost billions of dollars both in terms of the damage but also in fighting these fires as well and helping to protect people and what we've seen is that there seems to be a trend in that recent
• 08:00 - 08:30 fires are hotter so they're burning hotter they're burning the tops of the trees as well as just the forest floor they're larger so they're burning a greater area and they seem to be occurring more frequently and over more months of the year it used to be fire season was between a particular time of year and that is sort of getting longer and longer at each end and there are lots of really complex factors that go into wildfires so it can be that there's many causes behind some of these trends that
• 08:30 - 09:00 we're seeing so first of all we're just seeing increased human development at what we call this wildland interface so there are more people close to where the forests are we also in the 1900s and of that century saw fire suppression so especially in places where we were using a forest for timber we saw fire as a bad thing and we just put out all of the fires as soon as they occurred and what that did was it allowed fuel to build up on the forest floor usually
• 09:00 - 09:30 these smaller fires would come through and clear out that material on the forest floor but when that didn't happen when we put out all of the fires that built up over time and now when fires do occur there's lots of fuel there to burn and that tends to make these fires more intense it burns hotter and it tends to help that fire reach the canopy rather than just move along the floor it tends to kill more trees and then lastly of course we have climate change playing into this as well and so in this
• 09:30 - 10:00 particular lecture i want to talk more about what it is related to climate change that could cause these wildfires to get worse so this is my framework for thinking about the impacts of climate change on wildfire and so you can see that it's pretty complicated so we're going to go step by step so first of all if we start at the very top you can see that we have increasing temperatures we have more greenhouse gases in our atmosphere that's trapping more of that outgoing
• 10:00 - 10:30 infrared radiation and so that warms up our air temperatures and that has a number of different effects that you can see here the first is simply that we see increased evapotranspiration that means we have more water being lost from the leaves of plants as they're photosynthesizing we also see more evaporation from the soil it just means that the area ends up being drier overall because of these hotter temperatures and more evaporation the second one you can see in the middle
• 10:30 - 11:00 here is less precipitation and i've put a question mark here because we have a great deal less certainty when we talk about precipitation patterns and what's going to happen in the future it's something that it's really difficult to get right in our climate models but what we do seem to be seeing is that wet areas are getting wetter and dry areas are getting drier so what that means is that we seem to be seeing more flooding in certain places more drought in others and in the western us that seems to be leading
• 11:00 - 11:30 to less precipitation and more periods of drought that of course means that you end up with drier vegetation again because there's less rain there's less water available the other thing that's really important in the western us is the importance of snowpack so a lot of our rain in the western u.s falls in the winter or a lot of our precipitation and because it's falling in the winter and we have nice big mountains a lot of that precipitation actually falls as snow
• 11:30 - 12:00 and that means that instead of entering streams and running straight back to the ocean it collects and it builds up over the winter it basically acts like a natural reservoir storing that water for both the ecosystems and also humans because then as it melts away over spring and summer we have this source of water during the dry months that provides water to our trees and other vegetation but as we have increasing temperatures what we're seeing is that there's less and less
• 12:00 - 12:30 snow and more and more rain in the winter so we're not storing as much snow to begin with and it's melting away sooner which means that we have these later summer months where we really don't have that water source that we used to have and again that can go into drying out our vegetation and the drier our vegetation is it's easier for it to catch fire and when it does catch fire it can spread more easily it burns more intensely so we get these worse fires the last thing on my diagram that i
• 12:30 - 13:00 wanted to mention is actually based on some research that was done in our department which was looking at where fires seem to be happening where they weren't before and what was causing it and in particular we're seeing this increase in uh parts of in forests within alaska and parts of canada that we hadn't seen before and are quite a long way from humans and what we seem to think is that these increasing temperatures are increasing the likelihood that we have big storms
• 13:00 - 13:30 and so we get more lightning strikes in places that we didn't actually see before and so we're seeing this move north of these large fires uh burning places that we didn't usually have fires before and even into the arctic uh which is pretty much unheard of and so what the research tells us there's a really interesting research study done in 2016 was looking at what would have happened without climate change and what happened with climate change and what they came up with was that the
• 13:30 - 14:00 area burned between 1984 and 2015 in the western us is about twice what it would have been without climate change and so climate change isn't a small factor here it's actually a really significant factor in this sort of area burned because of all of these different impacts so why is it we should care about this why should we be concerned about wildfire so what harm does it cause so i have three images here to try and represent
• 14:00 - 14:30 that so in the top image here you're looking at the remains of an area of a town that burned in the alameda fire in oregon and you can see that it was really devastating people lost their homes and these fires especially when they're really fast moving can cause deaths and injuries there just isn't much time let alone the trauma of having to live through a really scary event like this it is not very fun and so it destroys homes infrastructure property and also has
• 14:30 - 15:00 effects on the timber industry agriculture tourism for example if you have to close areas like yosemite for example after fires in the bottom left hand side this image is actually from san francisco during the 2020 fires if you are on the west coast you may have experienced several days like this back in fall i know we did here in southern california as well whether the sky was completely orange it looked very apocalyptic and that's because of the particles the smoke
• 15:00 - 15:30 produced by these wildfires and that affects air quality in particular the particulate matter got this tiny particles that when you breathe in gets into your lungs and can cause damage but the other thing of course is that we're returning a lot of carbon dioxide to the atmosphere during these fires and that can amplify global warming so it's one of these positive feedback loops it's amplifying climate change and then on the right hand side you can see these other longer-term effects so
• 15:30 - 16:00 we're seeing destruction of ecosystems and habitat and especially where we're seeing these friars these fires happen more and more frequently we can actually see long-term changes in the type of vegetation that is growing in these places it also makes it easier for invasive species to come and colonize an area as well it can lower water quality and that's because we're losing the root systems and the vegetation that helps bind the soil together and so we get more and more erosion when
• 16:00 - 16:30 we get rainfall and that gets down into our streams and our rivers also the chemicals used for fighting the fires as well can get down and into those streams and harm aquatic ecosystems and then lastly something that happens a lot around the los angeles area is that when we get these big wildfires it again removes this vegetation removes the root systems holding the soil together also where we get these really hot fires we get this chemical on the the surface of the soil
• 16:30 - 17:00 that prevents water seeping in and so when we do get our winter storms the following winter we get more frequent flooding because that water doesn't seep down as much it runs across the surface and that also increases the risk of landslides as well so there's lots of associated hazards with this apart from just the fire itself so the question is what do we do about it because one of the main reasons that we study these things is because we want to better understand and try and mitigate the risk reduce the
• 17:00 - 17:30 risk to people and ecosystems so the first thing we can do is try and prevent as many fires from starting uh actually more than 80 percent of the fires in the us are actually created and started by humans so the rest are often caused by lightning strikes for example in those northern forests but especially where we have people close to the forests a lot of them are started by people and that can be an accident it can be someone with a campfire getting out of
• 17:30 - 18:00 hand or it can be arson sometimes and a couple of the big fires we've seen recently in california have been the cause of them has been ascribed to problems with the electricity grid the idea that we have these big transmission lines and when it's windy or if there's a fault it can create a spark which can trigger a wildfire and so one of the things that we're doing now in southern california is there's actually ways that you can shut down parts of the
• 18:00 - 18:30 transmission system so if you know that there's gonna be a really strong wind event then you actually shut down parts of the energy transmission system to try and prevent any uh chance of a wildfire happening obviously that causes other problems because it means that some areas might not have electricity for a while but that is one way of dealing with this the next thing we can do is we can try and manage our forests a little better we said that fire suppression caused this material to build up well what we can do is we could try and
• 18:30 - 19:00 have these controlled burns to clear out some of that vegetation when the weather conditions are suitable so we wouldn't get out of control so we could definitely manage our forests in a different way to help us reduce the intensity of fires when they do happen the next thing we can do is simply find ways of preventing deaths and protecting structures during fires we sort of know they're going to happen so what is it we can do to help so the first would be let's educate people let's come up with plans so that
• 19:00 - 19:30 we have evacuation routes people know what to do there are warning systems that make sure that everyone hears about a fire when it happens and can get out and then also with structures well maybe we can think about the design of our buildings what they're made from the building materials we need to try and make sure that everyone understands to have a defensible space so an area around your home where you've cleared the trees away you've removed anything that might be flammable like gas tanks and then lastly we just need to plan better so
• 19:30 - 20:00 can we regulate where buildings are happening can we educate people can we restrict for example where people can have campfires what activities people are carrying out so all of these ways are great ways and you can no doubt think of many many more all right so with that i want to switch to the east coast and think about climate change and hurricanes so here you can see a large hurricane approaching the coast of the us louisiana here
• 20:00 - 20:30 so hurricanes are also known as cyclones or typhoons depending where in the world they are but they're all the same thing there are these huge storms that develop specifically over tropical oceans because they need warm water to form the number of them varies a lot from year to year and that makes it quite difficult for us to see a trend over time in terms of the number of hurricanes that are happening what we're seeing is that more and more people are living near the coast
• 20:30 - 21:00 and so even if climate change wasn't affecting the strength of hurricanes there are about three times as many people now near the coast that can be influenced and affected by the damage that hurricanes can cause so if we look at the research that's been done we really can't say right now whether climate change is going to increase the number of hurricanes or decrease or stay the same the research just isn't certain enough for that so we don't know that yet but what we do know is that hurricanes are very
• 21:00 - 21:30 likely to get stronger due to climate change and in fact we think we're already seeing that we seem to be seeing uh more of the category three four and five hurricanes those strongest hurricanes compared to the category one and two hurricanes these weaker hurricanes so one of the things that i want to do before we talk about climate change and and how hurricanes form is talk about why hurricanes cause damage what are the ways that they can
• 21:30 - 22:00 affect society and people and ecosystems well the first image in my top left is meant to show the damage that can be caused by strong winds so we're getting better and better at building our houses and infrastructure in a way that can withstand strong winds but these hurricane winds can be extremely strong and the stronger they are the more damage they cause for example they can cause trees to fall down onto buildings or across roads it can also bring down for example
• 22:00 - 22:30 our electricity transmission lines and cause power to be lost the top right diagram shows uh flooding and this is something that is very very common and incredibly damaging after our hurricanes often one of the the main sources of economic damage and that's because there is so much rain that falls uh over these areas that it just overpowers the ability of the natural stream channels to carry that water back to the ocean and so it spills out and spreads across the landscape
• 22:30 - 23:00 and then lastly at the bottom my two diagrams here are meant to represent storm surge and storm surge tends to be what causes most of the deaths and a lot of the damage along coastline specifically as a result of hurricanes so what is a storm surge why should you be worried about that well the idea is that these hurricanes are associated with really strong winds and those winds push water up towards the coastline as that hurricane moves towards the coast it pushes water
• 23:00 - 23:30 ahead of it and that ends up raising the level of the ocean so in my right hand diagram at the bottom here you can see the bottom line here represents the mean sea level this is the average sea level over time the arrow above that shows the high tide so you have to be lucky and hope that your storm surge doesn't get associated with that extra amount of high tide and then above that you can see that the level of the ocean has risen way above and that storm
• 23:30 - 24:00 surge for weaker hurricanes can be maybe just a foot or something that wouldn't be noticeable but in really large powerful hurricanes it can be maybe 20 30 feet and that can be really devastating because the whole ocean rises over many hours to be much higher than usual that allows that water to flood inland it can affect homes and then on top of that you have waves crashing and so if you have a home near the beach it's very very hard for that home to withstand that that building
• 24:00 - 24:30 tends to be very very damaged and you can see some of the effects of a storm surge from an area of florida in this image on the left hand side so really really devastating and one of the main ways that we get damage in these hurricanes so i wanted to talk a little bit about how hurricanes form what are the ingredients you need to form a hurricane because we need to understand that before we can understand why climate change might make them stronger so here is my diagram that i
• 24:30 - 25:00 tried to draw out like a little cartoon to show a hurricane so you can see that we're over the ocean water and i've taken a slice down through the hurricane usually you're seeing satellite images looking for above and it's sort of this big spiral we're taking a slice down through it and you can see that that hurricane consists of sets of these thunderstorms that are circulating around this central low pressure system and in particular
• 25:00 - 25:30 those uh storm clouds get stronger and stronger into the middle and and these uh really tall clouds here on either side of that central eye the eye of the hurricane the the walls on either side are called the eye wall and this is where the most damaging hurricane conditions tend to happen as the hurricane moves across so let's look at my labels here to try and understand how our hurricane forms so the first thing that we need in order to form a hurricane is warm water and by
• 25:30 - 26:00 warm water i mean really warm greater than 80 degrees fahrenheit which is about 26 degrees celsius so that's why these really only form in the tropics we then have warm air above the ocean and we get evaporation of that lovely warm ocean water into the air so we end up with lots of water vapor contained within our warm air because we have this central low pressure system this is our center of the storm we have air moving from high pressure to
• 26:00 - 26:30 low pressure so that air tends to converge into the middle of the storm it spirals inwards because it's affected by the coriolis force as well so it spirals inwards to the middle and because it's all moving inwards once it gets to the middle there's nowhere really it for it to go other than up so it's forced upwards and you can see it spirals upwards with most of that air rising within the eye walls on either side of the eye so as that air rises
• 26:30 - 27:00 something really interesting happens which is that air cools down and all of the water vapor that that gaseous form of the water within the air condenses out and this is where we we managed to fuel our hurricanes so let me take a step back for a second and remind you that one of the reasons that we sweat is that that helps cool us down so we produce little droplets of sweat on our skin and as that water from the sweat evaporates that helps cool us down
• 27:00 - 27:30 it's because it takes energy away from our skin this is called a latent heat flux this amount of energy that's required by water in order to evaporate but here's the key thing when that water condenses again when it goes back from gas to liquid that same amount of energy that was carried away during evaporation gets released back so this condensation process releases heat to the surrounding air and that surrounding air warms up and
• 27:30 - 28:00 what does warm air do it rises and so as this moisture condenses we get this warming of the air which causes it to rise even further and because it's that air is rising even further that pulls more air in from underneath and so what we do is we create this this sort of everlasting loop where we have air converging and rising but then it's forced to rise even more because it's being heated and that pulls more air from underneath so it's self-sustaining this storm by the way this is why these
• 28:00 - 28:30 hurricanes tend to die away when you move on to land because once you're on land you no longer have lots of evaporation you cut off your source of moisture so we don't get as much condensation and so the storm just starts to fade away we can't fuel that storm anymore so it's really this condensation process that keeps that storm going and strengthens it over time and then there's one last thing on my diagram that i wanted to mention and it's over here on the left hand side this big red arrow
• 28:30 - 29:00 with a cross through it and what that is meant to show you is weak upper-level winds so the other thing we need for these hurricanes to form is something we call low amounts of wind shear which is low amounts of wind in the upper atmosphere and that's because what we want to do if we want a hurricane is we want to have all of that air rising in one central place if we have strong upper level winds it basically blows the hurricane apart instead that rising air is spread over a larger area and we do get that condensation
• 29:00 - 29:30 but it's not in one central place near the eye it's spread over a large plane area and it weakens the hurricane so those are the things we need for our hurricanes to form so the question you're hopefully asking is well how is climate change going to affect the strength of these hurricanes what particular aspects of the way that our climate is changing cause that to happen so here is my diagram uh trying to show those different features so the first thing i want to draw your
• 29:30 - 30:00 attention to is our surface ocean and i've drawn a red box here to to try and show that our surface ocean is getting warmer a huge amount of the energy about 90 percent of that extra energy that has been trapped on earth due to those greenhouse gases has actually gone into warming up the oceans so our surface ocean has been getting warmer and that makes it easier to evaporate we also get warmer air above the ocean that can hold more water vapor so we have more moisture in the air
• 30:00 - 30:30 we then have that air converging and rising and because there's more moisture that means that we have more condensation and because we have more condensation that means we get more rain so that strengthens the amount of rain we get and worsens flooding it also increases the amount of heat that is released and causes more air to rise and even more air to come in so that strengthens the winds because we get this stronger rising air pulling in more winds from
• 30:30 - 31:00 underneath and so we get this increase in rainfall increasing in strong winds and then the last thing that could cause damage was our storm surge so if we're getting stronger winds that's going to push more water so that's automatically going to worsen our storm surge but the other thing we have to worry about is that our sea level is also rising so our mean sea level is getting higher and so not only is the storm surge bigger but it's also going to be higher already because of
• 31:00 - 31:30 higher sea level so why is it that our sea levels are rising there's two main reasons the first is simply to do with the fact that it's warming up as something warms up the molecules move faster and in the ocean those molecules are moving faster they spread further apart and so what that does is that if you get four kilometers of ocean all spreading apart that creates a measurable increase in sea level that's something we call thermal expansion the fact that it's
• 31:30 - 32:00 warming up and that water expands the other reason of course is that we're seeing melting of ice in our glaciers on greenland and antarctica and that puts more water into the ocean and raises the level so that again worsens our storm surge the last thing i want to point out is again related to this wind shear these upper level winds i've been a question mark there because one of the reasons that we actually aren't sure what's going to happen to the number of hurricanes is because we think that this wind shear
• 32:00 - 32:30 might get stronger in the future and that might mean that we see fewer hurricanes but it's really uncertain so we just don't really know what's going to happen there so as we said before if we know it's going to happen we can do something about it our understanding of the scientific processes here and what impact it has means that we have an opportunity to try and prevent as much damage as possible so there are lots and lots of things you could do here i'm just giving you a few examples
• 32:30 - 33:00 of things that we could uh try so the first one is that if we know that sea levels are rising and that we have these storm surges can we build sea walls to protect our built environment and can we also make sure that we're preserving our natural defenses against storm surge many of you might have learned about ecosystem services well natural defenses against storm surge is one of these ecosystem services something that we get as a benefit from the natural ecosystems that exist and in particular along many of the
• 33:00 - 33:30 areas that are affected by hurricanes we get these amazing mangrove swamps and also mangrove forests and also we get coral reefs both of those are really good at reducing the strength of the waves reducing coastal erosion and their good protection against storm surge here you can see that we don't also have to rely on just concrete to build out our sea walls we can also do things like have these bamboo walls to try and slow down the waves and
• 33:30 - 34:00 protect against coastal erosion the next thing is well if we know that sea levels are rising if we know that uh that we're going to have stronger hurricanes in future which are going to cause more flooding well maybe we need to sort of draw a line and say you can't build in these places it's not responsible for our government to let people develop in certain places and if there are people living in really vulnerable places maybe we also need to help them relocate as well and then if we have
• 34:00 - 34:30 infrastructure like roads or electricity stations or water systems that are vulnerable we need to also either relocate them or protect them as well and that's related to storm surge near the coast but also flooding as well the next thing we can do is try and reduce urban runoff so where we have lots and lots of rain that can be made worse by our urban environment and that's because if we think about most cities what we imagine is lots of concrete everywhere and that concrete acts as what we call
• 34:30 - 35:00 an impermeable surface when rain falls that rain can't get through the concrete it collects on the surface and therefore runs off more quickly into our streams so even just with normal rainstorms our urban areas tend to be more at risk from flooding if we then add in hurricane strength rainfall then we're going to be in trouble and to be honest there's a certain amount that we can't really do for the amount of rainfall that we're going to get with hurricanes
• 35:00 - 35:30 if we look at for example at hurricane harvey um that hit texas there was i think 60 inches of rain which is a ridiculous amount of rain and it's going to be very difficult to protect against that sort of rainfall and that is going to become more frequent as we get this more moisture in the air more condensation more rainfall as well so that's something that we need to bear in mind when we're building our environments when we're dealing with our urban areas and then lastly we can think about
• 35:30 - 36:00 encouraging policies to build resilience so we need to preserve for example wetlands and floodplains further back in our drainage basin or our watershed because that also helps slow down the flow of water we can educate people about the danger of hurricanes we can help them prepare their own homes we can help them come up with evacuation plans for where they're going to go the government also provides a national flood insurance for example which is
• 36:00 - 36:30 actually required for people living in certain areas that are commonly flooded and then cities as well can plan how is it that we are going to help people deal with the effects of these stronger hurricanes in the future especially more vulnerable people and this brings me on to one last thing i want to say about extreme events specifically which is how it relates to environmental justice so when we look at the effects of natural disasters we see that people in poverty and
• 36:30 - 37:00 marginalized groups are disproportionately impacted by these events and there's a number of reasons for that if you want to read more i have a file a link down here which has a report explaining some of these things but here are just some of the reasons why that may be true firstly they may be less likely to receive warnings and even if they do receive warnings they may be less likely to evacuate or less likely to avoid the hazard so we saw that for example with hurricane katrina which is people who could evacuate did
• 37:00 - 37:30 but maybe people didn't have a car and so weren't able to evacuate or maybe you don't have the resources to go and stay in a hotel for a week to avoid something like that maybe they just can't the other example i have is down here in the bottom right hand corner this is something we see every year with climate with wildfires in the western us which is that one of the things you're recommended to do when we have these really bad smoky days is stay inside and avoid being outside
• 37:30 - 38:00 in that smoky air but if your job depends on you being outside for example our farm workers here then you don't have that choice and so you're more likely to be exposed to this hazardous hazardous air quality the next uh list thing on my list is that poorer people are unfortunately a greater chance of living in vulnerable housing that could be more affected by for example strong winds and in at-risk zones if you live in a
• 38:00 - 38:30 flood zone if you have a choice and you can afford it often you will move to somewhere that's less at risk and that tends to leave behind the people that can't afford to move somewhere else or it devalues your property price and so that means that it's hard to move away they also tend to have less access to health care less wealth to recover after a disaster so if there's a big disaster and you don't have a lot of savings it's difficult to repair your home to repair your business for example and
• 38:30 - 39:00 then also we tend to see that these marginalized groups tend to have less political power to advocate for themselves to advocate for help either before or after one of these events and an example of this is shown in the upper image here so this image shows an area of puerto rico about six months after hurricane maria and hurricane irma struck and you can see that the blue that you see there on the roofs is actually
• 39:00 - 39:30 tarpaulins where people's roofs have been damaged and they still haven't been fixed six months after an event and there is concern that uh depending on where you are and your political power there may be different amounts of resources provided to your region to help you recover after such an event and so given that we are seeing this increased probability of natural disasters related to climate change and we need to adapt and limit the risk and damage to people
• 39:30 - 40:00 that actually gives us an opportunity to be more proactive and actually address some of these equity issues and try and ensure environmental justice where we can where we have new policies so i wanted to end on a happier note because talking about climate change can be pretty depressing and pretty overwhelming it just seems such a huge problem and so i wanted to share an image with you that i use a lot in my college classes to try and give people a framework for thinking about action
• 40:00 - 40:30 because really the best thing that we can do to try and reduce the risk of these really devastating events is act to prevent as much climate change as we can that's going to reduce the risk of these extreme events and so this is a complicated diagram so let me walk you through it piece by piece so first of all we're going to look at the black writing and the black arrows and we're going to start at the very top at 12 o'clock so we can all agree that most of us have a desire for improved well-being for better lives
• 40:30 - 41:00 and what that tends to to do is create a demand for goods and services maybe we want better food maybe we want to travel maybe we want a new tv um and so that demand for goods and services in turn creates a demand for cheap easy energy um and in turn right now the way that we produce that cheap easy energy is using fossil fuels they are a great source of cheap easy energy but the problem is is that burning those fossil fuels produces co2 emissions
• 41:00 - 41:30 that enter our atmosphere so we're causing an increase in the co2 in our atmosphere and in turn that extra co2 is causing more warming of our climate it's causing our climate to change and it's also having negative impacts on our oceans for example through ocean acidification which is a huge potential problem and these negative impacts on our climate and our ocean and our ecosystems end up reducing our well-being they harm us but we want better lives and so you can
• 41:30 - 42:00 see that this cycle just keeps going and so the good news is that there's lots of places where actually we can act to prevent this cycle to prevent climate change and try and prevent a harm to people's lives so let's take a look at those actions and each of them is in red and marked by this sort of red line showing a break in the cycle so first of all we have a desire for improved well-being well does that necessarily translate into more stuff
• 42:00 - 42:30 can we think about encouraging people to think differently about diet do we get rid of say single-use plastic items or plastic packaging so can we somehow remove the demand for goods and services or reduce the extra demand for goods and services associated with people's lives getting better so that would be a conservation we're still going to have some demand for goods and services though we're not going to stop going anywhere or not use appliances and so can we actually
• 42:30 - 43:00 produce say refrigerators that don't need as much electricity or can we produce cars that get more miles per gallon of gas so in other words can we make our stuff more efficient in which case we reduce the demand for cheap easy energy however even if we make things really efficient we're still going to have some demand for cheap easy energy and so the good news there is that we have a lot of other options we have
• 43:00 - 43:30 solar energy we have wind energy hydroelectric biofuels all of those could be used uh as a way of reducing uh the amount of carbon emissions going into the atmosphere it's going to be difficult to completely change away from fossil fuels there's going to be some amount especially for the next sort of 50 years or so and so we are going to see some carbon emissions but can we use technology such as carbon capture and storage to actually capture that co2 for example
• 43:30 - 44:00 from a power station uh liquefy it and store it somewhere perhaps underground that's going to be difficult to do at a big giant societal scale but maybe in a few places we could use that and that could help us lower our emissions even further we are seeing still though that there are rising carbon dioxide levels in the atmosphere so can we prevent that from having negative impacts on climate and oceans so the next step that we could potentially do is have geoengineering and by that i
• 44:00 - 44:30 mean artificially messing with the climate system for example by increasing the amount of reflection from the earth by having more clouds or more aerosols in the atmosphere or can we do things that would help remove carbon from the atmosphere either artificially by creating some sort of industrial process or by planting trees for example which is something that we can and are doing right now that would help remove co2 from the atmosphere
• 44:30 - 45:00 uh however we are seeing negative impacts from climate change we are going to continue to see some climate changes into the future even if we act today and so it's really important that we take what we understand all of the things that you've learned about in your class about ecosystems about ecosystem services about climate about natural hazards and we use that information to come up with plans to adapt to that change to make sure that it doesn't uh reduce well-being as much as possible
• 45:00 - 45:30 especially across society not and taking care of the more vulnerable people as well so hopefully that has given you something to think about in terms of there's lots of things that we can do and what i want to point out is that this is not just an environmental science problem this is our entire society going to shift in the next decades and it's a tremendous tremendously exciting time to be around our world is going to look really really
• 45:30 - 46:00 different our society is going to look really really different in the next 30 40 years and the information that you've learned in your ap environmental science class is going to be really relevant for that no one is going to be able to opt out of that change and so the more you understand about this the more you understand the threats but also the opportunities for society the better off you'll be whether you end up in business in policy making running for public office or as an environmental scientist
• 46:00 - 46:30 somewhere acting to help these things so you're going to carry that information with you for the next decades and use it repeatedly as well so i hope you really value that opportunity it's going to serve you very well so with that i'll thank you for your attention and i'll wish you the best of luck in your exam in a couple of months