Data Exploration: The Direct Impacts of Climate Change
Data Exploration: Direct Impacts of Climate Change By Bennett SherryClimate change is altering our world in all sorts of ways. In this data introduction, we’ll explore some of the numbers behind the direct impacts of climate change.Learn more at www.oerproject.com
2Data Exploration: Direct Impacts of Climate Change By Bennett SherryDirect impactsThe direct impacts of climate change include global warming, rise in sea levels, extreme weather, forest fires, drought, and flooding. Later, you’ll learn about the societal impacts of those changes, which we call indirect impacts. But for now, let’s focus on one direct impact: sea-level rise.Greenhouse gas emissions are trapping heat in Earth’s atmosphere, causing a general rise in global average temperatures. As global temperatures increase, water that was once stored in polar ice sheets and glaciers melts and enters the oceans. As water gets warmer, it also expands. So, when temperatures in the ocean go up, so do sea levels.The long viewSea levels have fluctuated throughout the history of the Earth. Natural processes such as plate tectonics shifted continents and have both raised and lowered the sea floor. Ice ages and warming periods have alternated over hundreds of thousands of years, causing sea levels to rise and fall. Some people claim that the sea-level rise we’re seeing today is part of one of these long-term natural cycles. However, records from coral and ocean sediment cores tell us that for most of the last 2,000 years, as temperatures stabilized after the last ice age, sea levels have remained relatively consistent. Around the turn of the twentieth century, that changed: sea levels suddenly started to climb, and they haven’t stopped. From 1900 to 1993, historical tide records tell us that sea levels rose by four to five inches. In the 30 years between 1993 to 2023, the trend accelerated as sea levels rose another four inches. In Chart 1, on the next page, you can see why the trend is so alarming. These changes are accelerating rapidly, and they coincide with a change in human activity: the burning of fossil fuels.Effect of sea level rise on homes in in Summer Haven, Florida. © Getty Images. Data reminder:No matter how official a chart might look, and no matter how carefully the data was collected, data simply can’t tell the whole story. The data can change, or be represented differently, or we can learn a new and more effective way to capture certain data. This is not to say that you shouldn’t trust data—it’s an extremely important piece to understanding climate change. But data can quickly become outdated. We encourage you to seek additional, well-researched sources of data, and to let us know if you think something is out of date!
3Data Exploration: Direct Impacts of Climate Change By Bennett SherryChart 1: Global mean sea level since 1000 CE. By 2° Institute, CC BY-NC 3.0 DEED.The trend is even more apparent when we overlay global temperature anomaly (below in Chart 2, in grey) alongside sea level rise (in blue). Temperature anomaly is a way of measuring the increase or decrease in temperature from a baseline average.Chart 2: Sea-level changes and changes in global temperature anomaly over the last 1,000 years. From 2° Institute. (To see this view in the interactive chart, you must select “Global Sea Levels” from the top-right menu button and then click the thermometer toggle on the top-left to overlay temperature anomaly). By 2° Institute, CC BY-NC 3.0 DEED.
4Data Exploration: Direct Impacts of Climate Change By Bennett SherrySee? Change.Let’s dig into the last 150 years of data and see how the rate of sea-level rise has changed. Chart 3, below, shows a zoomed-in view of how sea levels have changed since 1880. How do we know about these changes? From 1880 to 1993, researchers relied on historical sea-level recordings collected from different ports around the world.1 In 1993, NASA started measuring sea levels with satellites, which provide more exact measurements from all over the globe.In the twentieth century, sea levels rose an average of 1.7 mm (0.07 inches) per year. By 1993, the rate had accelerated to 2 mm. In 2016, it reached 3.4 mm per year. By 2022, it had increased to 4.4 mm per year, more than double the long-term trend in the twentieth century. By 2050, researchers predict that the rate will increase to 6.6 mm.2 This rate of acceleration could result in the sea level along the US coastline rising as much as 12 inches by 2050. That’s as much increase as was recorded in the 100 years between 1920 and 2020.3Chart 3. Sea-level rise, 1880 to 2002. From NOAA. By Our World in Data, CC BY. Explore Chart 3 here.1 Church, J.A., White, N.J. “Sea-Level Rise from the Late 19th to the Early 21st Century.” Surv Geophys 32, 585–602 (2011). https://link.springer.com/article/10.1007/s10712-011-9119-12 Note that these estimates vary depending on the source. However, the general trend of an increasing rate of increase is consistent across sources.3 EPA. “Climate Change Indicators: Sea Level.” https://www.epa.gov/climate-indicators/climate-change-indicators-sea-level#ref1
5Data Exploration: Direct Impacts of Climate Change By Bennett SherryWe’re in over our headsThese might sound like small numbers. After all, 3 mm is about the length of a sesame seed. So, what’s the big deal? Well, there are three issues:1. Over the course of decades, those small numbers really add up. If you stack enough sesame seeds, things get messy quickly.2. The rate of sea-level rise is accelerating, so those per-year numbers are going to get bigger.3. As you can tell in Chart 2, it takes a while for sea-level rise to catch up with the increase in temperatures. We won’t know exactly what a 1.5- or 2-degree rise in global temperature will mean for sea levels until after we’ve reached that threshold. We don’t really know how high the seas will rise by the end of this century, but the National Oceanic and Atmospheric Administration (NOAA) estimates that the oceans could rise between one and eight feet (0.4 to 2.4 meters) by the year 2100 (see Chart 4). That’s a big difference. Scientists are almost certain that sea levels will continue to rise until the year 2100. How much they rise, however, will depend on how quickly humanity moves to reduce our greenhouse gas emissions.Chart 4:This chart shows future sea levels through 2100 for six possible scenarios. These predictions vary based on future rates of greenhouse gas emissions and rise in global temperatures. By climate.gov. Humanity and the seaWhat does the variation in the level of sea rise mean for the world? What does it mean for you and your community? To begin answering those questions, let’s take a look at Map 1, below.
6Data Exploration: Direct Impacts of Climate Change By Bennett SherryMap 1: Global population density. Courtesy Visual Capitalist. Did you notice that you can recognize the shape of most of the continents even though there are no borders, no coastlines, no oceans—just population density spikes? That’s because a lot of Earth’s population lives very close to the ocean. Take a look at Map 2, below. About 40% of Earth’s population lives within 100 km (about 60 miles) of a coast. Eight of the top ten largest cities in the world are on a coastline. Sea-level rise is a huge problem for humanity because coastal regions are very densely populated, and coastal populations are increasing. By the end of the twenty-first century, over 410 million people are expected to be at risk from rising seas. This will not only affect small island nations in the Pacific Ocean, such as Kiribati and Tuvalu, Map 2. Coastal populations and shoreline degradation. Courtesy PRB.com.
7Data Exploration: Direct Impacts of Climate Change By Bennett Sherrywhose very existence is threatened. If sea levels continue to rise at the current rates, flooding and weather events will drive massive migrations on every continent. Coastal communities will be even more vulnerable to extreme weather events like flooding, hurricanes and typhoons. Coastal regions are critical to international economics and infrastructure, including fisheries, shipping, and tourism—which is why so many people live along the coast.To make matters worse, the charts above deal with average global sea-level rise. In reality, sea-level changes are different from place to place, and are based on factors such as geography and gravitational pull. Coastal regions will experience sea-level rise unequally, depending on available infrastructure, such as levees and dams. In some regions, sea-level rise has been and will be far worse than the global average would indicate, thanks to issues like erosion and drilling. Despite less than a foot of global sea-level rise, high-tide flooding is 300% to 900% more frequent than 50 years ago.4 Coastal communities are already experiencing the consequences of this direct impact of climate change.If you live inland, maybe in Colorado or Iowa, you might think you’re safe from this direct impact. But even landlocked regions will be affected by the indirect impacts of coastal flooding: economic damage, supply-chain disruption, migration, food shortages, and other, unforeseen changes. You’ll learn more about these soon. ConclusionSea-level rise is caused by climate change, which is caused by human activity. It threatens coastlines all over the world and the 40% of humanity who live there. But sea-level rise will affect all of us, not just those who live on the coast. Sea-level changes, like climate change in general, will affect communities unequally. As you review the data and tools in this article, think about what people and regions of the world will be most at risk from the direct impacts of climate change. If you want to explore more about what sea levels will mean for your community or for your favorite coastal cities around the world, you can check out these tools, maintained by NOAA and NASA:NOAA Sea Level Rise Viewer: This tool shows how the US coastline will change if sea levels rise between 1 and 10 feet. For some locations—like Fulton Street in Manhattan—you can see a visual estimate of how a place will change based on sea-level increase.4 Lindsey, R. “Climate Change: Global Sea Level.” Climate.gov. https://www.climate.gov/news-features/understanding-climate/climate-change-global-sea-levelNOAA Sea Level Rise Viewer.
8Data Exploration: Direct Impacts of Climate Change By Bennett SherryNASA’s IPCC AR6 Sea Level Projection Tool: This tool allows you to see predicted sea levels around the world in different years based on several different warming scenarios. NASA’s IPCC AR6 Sea Level Projection Tool
9Data Exploration: Direct Impacts of Climate Change By Bennett SherryBennett SherryBennett Sherry holds a PhD in history from the University of Pittsburgh and has undergraduate teaching experience in world history, human rights, and the Middle East at the University of Pittsburgh and the University of Maine at Augusta. Additionally, he is a research associate at Pitt’s World History Center. Bennett writes about refugees and international organizations in the twentieth century.Credit: “Data Introduction: Direct Impacts of Climate Change ”, Bennett Sherry / OER Project, https://www.oerproject.com/Image credits This work is licensed under CC BY 4.0 except for the following: Cover image: Direct effects of climate change: drought, crop stress, and sea level rise. © piyaset / iStock / Getty Images Plus.Effect of sea level rise on homes in in Summer Haven, Florida. © Aerial_Views / E+ / Getty Images.OER Project aims to empower teachers by offering free and fully supported history courses for middle- and high-school students. Your account is the key to accessing our standards-aligned courses that are designed with built-in supports like leveled readings, audio recordings of texts, video transcripts, and more. Offerings include a variety of materials, from full-year, standards-based courses to shorter course extensions, all of which build upon foundational historical thinking skills in preparation for AP, college, and beyond. To learn more about The OER Project, visit www.oerproject.com