Warming Trends: Increasing Heat is Dangerous for Pilgrims, Climate Warnings Painted on Seaweed and Many Plots a Global Forest Make

A column highlighting climate-related studies, innovations, books, cultural events and other developments from the global warming frontier.

Prospective pilgrims walk on the road, which has water spray cooling system, to stone Jamarat pillars that symbolize the devil as a part of the annual Islamic Hajj pilgrimage during the first day of Eid Al-Adha in Mecca, Saudi Arabia on Sept. 2, 2017. Credit: Firat Yurdakul/Anadolu Agency/Getty Images
Prospective pilgrims walk on the road, which has water spray cooling system, to stone Jamarat pillars that symbolize the devil as a part of the annual Islamic Hajj pilgrimage during the first day of Eid Al-Adha in Mecca, Saudi Arabia on Sept. 2, 2017. Credit: Firat Yurdakul/Anadolu Agency/Getty Images

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Global Warming Poses Danger to Pilgrims

Millions travel to Mecca in Saudi Arabia every year to fulfill one of the five pillars of the Islamic faith—the “hajj,” a pilgrimage to the sacred city every Muslim who is able must take. But the physically demanding experience, which requires long walks and sleeping in tents in one of the world’s hottest cities, will become more dangerous for pilgrims as the planet warms, a recent study found.

During the hajj this week, temperatures in Mecca hovered between 100 and 110 degrees Fahrenheit. Only 60,000 people were allowed to attend the annual five-day pilgrimage because of Covid-19 restrictions, but ordinarily, more than 2 million Muslims from around the world gather to perform rituals like the symbolic stoning of the Devil, circling the cube-shaped Kaaba and walking between the two hills of Safa and Marwa seven times.

But Mecca, a desert city located about 40 miles inland from the Red Sea, can be a perilous place for large outdoor gatherings and physical activity. Winds blow humid air from the sea into Mecca, which combined with the sweltering desert heat create conditions that can lead to heat exhaustion and deadly heat stroke. 


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Fahad Saeed, a climate scientist at Climate Analytics, said the risk is not as high for people who live in Saudi Arabia and are used to the conditions. “But those who are coming from other parts of the world, especially the elderly, it becomes dangerous,” he said.

Saeed led a study in Environmental Research Letters that used wet bulb temperatures—a metric that combines both heat and humidity—to estimate the risk of heat stroke for pilgrims in Mecca over the coming decades. He and his colleagues found that if global temperatures warm 1.5 degrees Celsius above pre-industrial levels, the risk of heat stroke during the hajj would increase by a factor of five. If temperatures warm 2 degrees Celsius, the risk would increase by 10.

Some aspects of the hajj have already been adapted to the heat. Some tents where pilgrims stay have been outfitted with air conditioning, for example, and the walk between Safa and Marwa takes place in a long building connecting the two hills, where it is kept cool. 

Although air conditioning is becoming necessary, Saeed said it comes at a cost, and he considers it a damaging impact of climate change on a sacred tradition of one of the world’s largest faiths. 

“This will result in the loss of the religious heritage in a way that the very sense of the ritual will be lost,” he said. 


For Monarch Butterflies, Heat Means Population Decline

Although monarch butterfly populations have faced habitat loss with the increased use of herbicides, the primary reason for their decline is climate change, a new study has found

An analysis by researchers at Michigan State University of 18,000 surveys conducted over a 25-year period, largely by volunteers, found that the weather conditions in spring and summer breeding grounds from Texas to the Midwest and Southern Ontario, was seven times more important in determining monarch population levels than other factors, like the loss of milkweed habitat and mortality of butterflies during the autumn migration.

In the spring breeding grounds, like Texas, and parts of the summer breeding grounds, like Iowa and Ohio, monarch populations were highest when temperatures were more moderate, and they declined when temperatures were above normal.

“Even if the decline wasn’t a really steep decline, they were still declining and that was tied to some of these things like increases in temperatures throughout the summer breeding range,”  said Erin Zylstra, lead author and a postdoctoral researcher at Michigan State. “Obviously the implications of the long term climate projections are a little bit worrying. We expect temperatures to increase both in the spring and summer breeding grounds.”

The decline of monarchs in the mid-1990s and early 2000s was associated with an increased use of herbicides that wiped out milkweed plants on farmland, Zylstra said, and milkweed is the only plant on which monarchs lay their eggs. The data from the last two decades shows that climate has become the main driver of the changes in monarch populations as the planet warms.

This knowledge is helpful for future efforts to protect monarchs, Zylstra said, because conservationists can target places where temperatures may be milder, rather than places where warming may be too extreme, giving monarchs a better opportunity to survive.

“We should be thinking about cutting carbon emissions personally and advocating for our communities, politicians, governments to do more to cut carbon emissions,” Zylstra said. “It’s not only good for monarchs, it’s good for lots and lots of stuff.”


Red Signals Danger in Maps Painted on Seaweed

On world maps showing the projected impacts of the climate crisis, the color red often dominates, symbolizing the most extreme conditions, the biggest risk or the highest danger. 

When artist Christina Conklin paints copies of such maps onto thin sheets of seaweed that she harvests directly from the ocean and dries into flat pieces of parchment, the color red stands starkly against the translucent background. 

“They’re kind of beautifully terrifying maps,” she said. “I just transcribe them because that seems like the best way to do this kind of art-science hybrid.”

Christina Conklin's art shows Antarctic ice stream speed on a piece of dried seaweed. Credit: ©Christina Conklin
Christina Conklin’s art shows Antarctic ice stream speed on a piece of dried seaweed. Credit: ©Christina Conklin

Conklin’s climate maps on seaweed appear in a new book she co-authored with Marina Psaros called The Atlas of Disappearing Places. The book features 20 locations in and around the world’s oceans, including cities like New York and Shanghai and more remote places like Vietnamese rice paddies and the dead zones of the Arabian Sea. Each place includes a speculative vision of the future if climate change is not quickly halted, a collection of climate solutions taking place in that area and Conklin’s unique seaweed art. 

The book’s focus is on the ocean, which Conklin compared to a human body. The warming ocean has a fever, she said, and by the time sea level rise really begins to make coastal cities unlivable, it will be like the ocean is in intensive care, on the brink of death. 

She hopes the book inspires readers to understand the gravity of the climate crisis, without losing hope for the future. 

“The little bit of change we’ve experienced so far is a thin little edge of the wedge,” Conklin said. “What we need to do now is get really, really focused in the 2020s to have a different story for our children and our grandchildren.”


Mining Humans’ Cultural Past for Keys to Survival in a Warming Future

Fighting climate change and protecting biodiversity often go hand-in-hand. But what about cultural diversity as a climate solution? 

A new scholarly discipline, the archaeology of climate change, aims to find lessons in past cultures that can help negotiate the future challenges of global warming. 

In a Perspective in the Proceedings of the National Academy of Sciences, researchers from France, the United States and Canada argue that by studying how societies and ecosystems of the past changed during earlier periods of atmospheric warming, archaeologists can discover important information, like the tipping points that led humans to move and reorganize their societies, and whether those efforts were successful. Co-author Ariane Burke, who runs the Hominin Dispersals Research Group, said cultural diversity was an important factor in successful adaptation to past climate changes.  

The impacts of climate change that we face today vary from flooding in Europe to wildfires in the United States, she said, and “we need more than one strategy, and cultural diversity is one of the things that allows us to quickly draw on this sort of library of alternative strategies, and be able to react quickly to what’s going on.”

An example of what we can learn from this new discipline, Burke said, is how indigenous farming practices used traditional knowledge gathered over generations of living on the land to grow crops in ways that are more friendly to the ecosystem and more resilient in the face of climate change than industrial crops and agricultural practices. 

“Having a monoculture of human culture exposes us to danger because we don’t have enough alternative strategies that we can draw upon should our main strategy fail us,” Burke said “It’s like a great big experiment, the more experiments you run, some of them will be successful.”


How Thousands of Tree Plots Add Up to a Global Forest

Some of the most vital research on the world’s tropical forests has been meticulously carried out, year after year, by local scientists who know their plots of trees by heart.

A collective database is now bringing together these scientists and their years of measurements to stitch together a comprehensive picture of important forest ecosystems. Founded in 2009 and managed by the University of Leeds in the U.K., ForestPlots.net has connected 2,512 scientists in 59 countries, studying over 5,000 plots of forest land. A new study in the journal Biological Conservation shows how this database has helped scientists standardize measurement practices to create a global collection of tree knowledge that is informing our understanding of climate change. 

“The idea is to support a worldwide grassroots community of field investigators with deep knowledge of particular patches of forest,” said founder Oliver Phillips, a professor of tropical ecology at the University of Leeds. “ForestPlots is both this connected community of researchers and the database that brings their work together.”

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The database has enabled discoveries that wouldn’t have been possible without such complete and detailed information, Phillips said. For example, the data can show how tropical forests vary in diversity and productivity and how much carbon tropical forests are absorbing, helping to mitigate climate change.

“We shouldn’t forget the number one priority from a biodiversity viewpoint and a climate control viewpoint is to conserve what we already have standing,” Phillips said. “Intact forests are a really big part of the solution, that’s where the science can really contribute and make sure this message comes out loud and clear.”