Geography in the News: Story at a Glance - Climate Change (Guest blog)

Geography in the News is an old concept, made new again with every new wall display and resource sheet. But here guest blogger, Stephen Schwab, suggests a new twist - curating articles to create a through flow of ideas and concepts. Articles can be edited for different reading ages and tasks added to aid the learning.

Students get up-to-date examples and case studies beloved of exam boards, and it helps them to understand the idea of interconnectedness so important in our subject.

These three stories came from one day [Bloomberg Green, The Hill, Quartz] but can be curated over time to add in the concept of changes over time - they all focus on climate change.

Story at a glance: Much of the US Will Be an ‘Extreme Heat Belt’ by the 2050s

A heat model released Monday by researchers from the First Street Foundation estimates heat risks at the property level across the U.S. Researchers found the local hottest seven days of any particular area are expected to become the hottest 18 days over the next 30 years. By 2053, 1,023 counties could experience heat index temperatures above 125 degrees.

The heat model released Monday by researchers from the First Street Foundation estimates heat risks at the property level across the U.S. and how the intensity of hot days will change over the next three decades. The model identified the seven hottest days for any property this year and used that metric to determine how many of those days would occur in 30 years. Researchers found the local hottest seven days of any particular area are expected to become the hottest 18 days over the next 30 years. Miami-Dade County may experience the most dramatic shift in temperature, where the region’s seven hottest days, which include heat index temperatures at 103 Fahrenheit degrees, could increase to 34 days a year at that temperature by 2053.

The states expected to see the largest increase in dangerous temperatures are Texas, Arkansas, Louisiana, Missouri and Florida. According to the model, an “extreme heat belt” will encompass an area stretching from Texas and Louisiana to Illinois, Indiana and even parts of Wisconsin. By 2053, 1,023 counties could experience heat index temperatures above 125 degrees, an area home to more than 107 million that covers a quarter of U.S. land area. The model also estimates that just next year, 50 counties are expected to see temperatures beyond that figure.

In three decades, more than 100 million Americans will live in an “extreme heat belt” where at least one day a year, the heat index will exceed 125° Fahrenheit (52° Celsius) — the top level of the National Weather Service’s heat index, or the extreme danger level. (The index combines temperature and humidity to arrive at how it feels when you go outside.)

The future heat belt is a huge swath of the country that includes the Southeast and the area just west of the Appalachian Mountains, stretching from Texas and Louisiana all the way up through Missouri and Iowa to the Wisconsin border. This is not the part of the nation we most associate with heat, but since it is inland there are “no coastal influences to mitigate extreme temperatures,” and many communities “are not acclimated to warmer weather relative to their normal climate,” the report states. The sharpest heat increase, however, will be felt in Miami-Dade County, Florida, where the hottest days now, those reaching 103°F, will increase in frequency from 7 days a year to 34 by 2053.

The findings are part of the sixth report by First Street to help Americans picture how warming will impact them at home. Previous reports looked at fire and floods, and the foundation made available fire and flood risk scores for every property in the contiguous US on its website. According to the report, across the country, on average, peak temperatures now on the hottest 7 days per year will be reached 18 days a year in most localities. While you might not lose your home to extreme heat, it certainly has other risks. The recent heat wave in the Pacific Northwest sent almost 1,000 people to the hospital. Power grids experience blackouts, knocking out air conditioning. People can experience exhaustion and dehydration as temperatures soar and can die from heatstroke. Bridges and roads buckle. Wildlife is affected.

Temperatures are notoriously difficult to predict accurately even a few days out, much less 30 years. However, there are differences between climatology and meteorology. First Street uses climatology modelling that shows rising global temperatures based on the current level of greenhouse gas emissions to predict warming trends. Then it layers on address-specific information, such as how much tree canopy cover is nearby, or whether a home in an urban area is surrounded by impervious surfaces, like parking lots, that absorb and retain heat.

Story at a glance: Even small temperature changes will significantly affect North American forests

We have known for a long time that increasing global temperatures spell concern for a host of plant and animal species, along with human health, but new research demonstrates the extent of damage resulting from slight temperature increases on North American tree species. Results show that in addition to increased mortality, warming would significantly restrict growth for some species and effects will be compounded by reduced rainfall.

An analysis of more than 4,500 seedlings of nine North American tree species revealed just a slight temperature increase of 1.6°C alone, or combined with reduced rainfall, would increase mortality among the trees and significantly restrict growth.

The research, carried out by a team at The University of Michigan, was published in the journal Nature and underscores the precarious situation of North American boreal forests seen throughout Alaska, Canada and parts of Michigan and Minnesota. These areas are one of Earth’s largest nearly intact forested ecosystems and play a significant role in decreasing human-made carbon emissions; they are located below tundra regions but above more temperate forests.

Over five years, researchers used infrared lamps and soil heating cables to study near-term impacts of warming on the seedlings. Several common northern conifer species including balsam fir, white spruce, and white pine exhibited severely reduced growth under experimental conditions, while modest warming did enhance growth for some species more commonly found in southern temperate forests. However, the enhanced growth of these species is not enough to offset the effects of the vanishing conifers, researchers warned.

In addition to testing the effects of a 1.6°C warming, researchers also tested outcomes of a 3.1°C increase above ambient temperatures. Rainwater tarps were used to test drier conditions and outcomes were compared with control trees grown at ambient temperatures and under normal moisture conditions. Data showed reduced rainfall exacerbated the effects of slight temperature increases.

“Our results spell problems for the health and diversity of future regional forests,” said study co-author Peter Reich of the University of Michigan in a statement. “Present-day southern boreal forest may reach a tipping point with even modest climate warming, resulting in a major compositional shift with potential adverse impacts on the health and diversity of regional forests,” he added.

The resulting consequences could have sweeping impacts on forests’ ability to produce timber, host other plant and animal biodiversity and reduce flooding and carbon in the air.

Story at a glance: Spruce trees have arrived in the Arctic tundra a century ahead of schedule

As climate change decimates forests in places like Europe and the American west, boreal trees are moving into the Arctic. Young white spruce are now growing in the tundra, where climate scientists did not expect them to be for another hundred years or more, according to a new study conducted in Alaska.

The paper, published this month in Nature, found the tree species, which normally grows in the middle of Alaska, is expanding north into areas where cold temperatures previously limited vegetation to low shrubs and lichen. Its authors, researchers from Alaska Pacific University, University of Alaska Anchorage, Amherst College, and Northern Arizona University, estimate the spruce are gaining around 4km per decade, faster than any documented high-latitude population of conifers.

The findings underscore new research that shows scientists underestimated the speed at which the Arctic is melting. It is warming up four times faster than the rest of the world, transforming ecosystems, upending migratory patterns of animals, releasing and redistributing carbon—and creating the environmental conditions for conifers to grow.

All of this will have global implications. Migrating forests exacerbate the effects of climate change. More trees in the tundra mean less sunlight reflected off the ground and absorbed by vegetation instead, leading to further melting of Arctic ice.

Boreal conifers can jump from location to location, and travelled over mountains into the tundra, according to Roman Dial, the lead author of the study. It’s possible tree seedlings have taken root in other remote, inaccessible areas of the tundra that scientists have not yet discovered, the authors said. Young trees are hard to detect even with satellites. The scientists first discovered the spruce trees in 2019 during a field study. Because little is understood about how trees are adapting to climate change, discoveries like these are invaluable, helping scientists learn how to protect and reproduce species at risk now or in the future.