EarthTalk®

Dear EarthTalk: How has the huge footprint of humanity forced other animal and plant species to evolve differently than they might otherwise have without people around? – Lois V., New York, NY

Humans have profoundly altered the planet, driving plants and animals to adapt in ways they never would have without our impact. Through activities like habitat destruction, pollution, climate change, hunting and introducing invasive species, humans have significantly accelerated evolutionary changes, transforming ecosystems in dramatic and often unpredictable ways.

One example is the rise of tuskless elephants. Decades of ivory poaching have created intense pressure on African elephants. In regions of heavy poaching, up to half of female elephants are now tuskless, an adaptation showing how humans can profoundly alter the genetic makeup of another animal population.

Urban environments have also become hotspots for what some researchers consider accelerated evolution. During the Industrial Revolution, peppered moths in England evolved darker colors to blend into soot-covered trees. Today, insects and city-dwelling birds are similarly adapting to human-made conditions. Pigeons have modified their eating habits to thrive on discarded food, and some mosquito species have adapted to reproduce in tiny water collections present in city environments. These alterations illustrate the adaptability of species adjusting to environments changed by humans.

Chemical resistance is another area where human influence is clear. The widespread use of pesticides and antibiotics has driven the evolution of resistant pests and bacteria. Farmers battle “superweeds” that can survive herbicides, and healthcare providers face rising concerns over antibiotic-resistant bacteria.

Climate change has further expedited evolutionary shifts. Animals are altering their migration patterns and breeding seasons to adapt to warmer temperatures. Birds like the great tit in Europe are laying eggs earlier in the spring to align with the availability of insects. Similarly, marine species are moving to cooler waters. This disrupts ecosystems and fisheries

These adaptations showcase the nature’s incredible resilience, despite some notable drawbacks. Rapid evolution can lead to reduced biodiversity, as species unable to adapt face extinction. Ecosystem imbalances arise as invasive species prevail, pushing out native organisms. According to the National Wildlife Federation, human activities are driving an unprecedented rate of evolutionary change. To help, choose sustainably sourced products, reduce waste, and support conservation efforts to protect habitats and species. Advocacy for policies that address climate change and pollution is also key.

CONTACTS: Scientific American article on human-driven evolution: www.scientificamerican.com/article/humans-are-driving-a-new-kind-of-evolution-in-animals/. 

Dear EarthTalk: What exactly is congestion pricing as just implemented in New York City and how will it help the environment? Should other cities also adopt this policy? – H.M., San Diego, CA

New York City recently became the first U.S. city to implement congestion pricing, a strategy aimed to reduce traffic in extreme congested areas by charging drivers a fee during peak hours. This approach not only helps alleviate traffic but also provides notable environmental benefits.

Congestion pricing seeks to manage demand for road space in busy areas. Drivers pay a fee to enter these zones with electronic tolling systems that track vehicles and collect payments. The revenue generated is usually invested into improving public transportation and infrastructure. For example, New York plans to issue these funds toward improving its subway system, which millions of residents depend on daily.

Reducing the number of vehicles on the road improves air quality. Fewer cars mean lower greenhouse gas emissions and less air pollution, major contributors to climate change and public health problems. Cleaner air also means fewer respiratory issues for residents mainly in the areas near major traffic hubs.

Beyond environmental gains, congestion pricing makes cities more tolerable. If traffic congestion decreases, it leads to faster commute times and less stress for drivers. Streets become quieter and more friendly for pedestrians. Walking and biking are encouraged more if streets are convivial. Cities like London have seen a 30 percent reduction in traffic volumes after executing congestion pricing; there have also been crucial improvements in public transit reliability.

Critics of congestion pricing usually point to worries about fairness. This is generally notable for low-income drivers who may struggle to afford the fees. Small businesses that rely on vehicle deliveries also worry about added costs. However, advocates of congestion pricing argue that the advantages outweigh these challenges. Investments in public transit can make commuting more attainable and affordable for everybody; programs offering discounts or exemptions can help mitigate the impact on vulnerable groups.

Individuals can play a key role in helping congestion pricing succeed. Reduce your own driving by using public transit, biking or walking when possible. Participate in community discussions or campaigns that support congestion pricing. Volunteer or donate to groups advocating for sustainable urban planning. Moreover, you can educate others about the benefits of congestion pricing and how it improves urban life. Support local policies that fund clean energy solutions or improve bike and pedestrian infrastructure. Together, we can create cleaner and less congested urban environments for everyone.

CONTACTS: Better Cities Project: https://better-cities.org; U.S. Department of Transportation Congestion Pricing Resources: https://ops.fhwa.dot.gov/congestionpricing.

Dear EarthTalk: I’ve heard that cattle cause a large share of global methane emissions that fuel global warming. What can be done besides reducing or eliminating meat consumption? – N.V.

Methane is a greenhouse gas that is 28 times more potent than carbon dioxide (CO2) when trapping heat in the atmosphere and is responsible for nearly half of the 1.1-degree Celsius increase in global temperatures. The gas is short-lived and gets broken down into CO2 and water vapor after a decade.

Cattle are ruminants: their stomachs allow them to digest fiber-rich foods like grass and hay. This produces methane, expelled as gas when cattle belch. Every year, a single cow will belch around 220 pounds of methane, which is oxidized to CO2, absorbed by plants and reintroduced into cows’ diets.

One of the most promising ways to reduce methane is altering cows’ diets. Methane is primarily produced by the digestion of fiber, so feeding cattle grains and fats like corn and barley may lower methane output. A study led CU Boulder, NIST, and Kansas State University explored this idea, feeding cows sorghum, a more sustainable crop requiring less water and fertilizer. Initial findings reveal minor differences in emissions, but further research will determine if these changes are statistically significant. Another approach, tested by scientists at UC Davis, involved adding one percent red seaweed to cattle feed, which reduced methane emissions by up to 60 percent without affecting milk production.

Another potential solution is genetic selection. Cattle living on the same farm, eating identical amounts of feed, can produce different amounts of methane because of certain genetic traits. Scientists are exploring possibilities of breeding for these traits or breeding cattle with bulls to reduce emissions. Additionally, methane reducing feed additives, which incorporate less than one percent of cattle diets, can interrupt the methane-formation process and reduce emissions. However, certain additives require further approval for animal health. Methane-reducing vaccines are also a viable solution that requires further testing, and are unlikely to be available before the end of the decade.

Changing management practices is expensive and many farmers have no economic incentives to adopt such methods. Therefore, many countries and organizations are developing a Payment for Environmental Services (PES) program to financially support these changes. Economists argue that these programs need to be tailored to meet the specific funding needs of farmers across different regions. Emissions intensity varies greatly across different countries based on their income level, with 6-16 times more intense emissions in lower income countries, due to less efficient systems.

Anyone can make a difference by supporting sustainable agriculture, advocating for policy changes, reducing food waste, adopting a plant-based diet and spreading awareness about this issue.

CONTACTS: Making Cows More Sustainable, https://www.ucdavis.edu/food/news/making-cattle-more-sustainable.

Dear EarthTalk: What is Jimmy Carter’s environmental legacy? -- B.N.., Athens, GA

Jimmy Carter, the 39th U.S. President, made a lasting impact on environmental policy. His robust initiatives to protect natural resources and advance clean energy established the foundation for environmental policy in subsequent decades. Despite obstacles, his efforts in land preservation, energy efficiency and climate activism still impact environmental policy in the present day.

One of Carter’s most significant actions, a symbolic one, was installing solar panels on the White House. And he signed the National Energy Act, which reduced U.S. dependence on foreign oil and encouraged the use of alternative energy sources. “The energy crisis is real. It is worldwide. It is a clear and present danger...” Carter stated during his presidency, emphasizing the urgency of moving to sustainable energy. Carter also created the Department of Energy in 1977 to consolidate management and energy policy. The move displayed his foresight in addressing energy security and climate issues. This laid out the groundwork for the renewable energy sector’s growth in subsequent decades.

Carter’s dedication to conservation was equally effective. His administration included multiple wildlife reserves, national parks and public lands in the federal portfolio. Specifically, he enacted the Alaska National Interest Lands Conservation Act in 1980, which protected over 100 million acres of Alaska wilderness, enlarged the National Park System and protected priceless ecosystems for future generations. Reinforcing existing environmental codification was another order for Carter. He reinforced the Clean Air and Clean Water Acts, and in 1980, signed the Superfund law to clean up hazardous waste sites.

After leaving office, Carter continued to work for the environment. Through the Carter Center, he promoted sustainable farming and clean energy. His work with Habitat for Humanity promoted affordable and sustainable housing as a foundation of environmental and social justice. “Habitat has successfully removed the stigma of charity by substituting it with a sense of partnership,” Carter voiced. Carter’s environmental vision faced difficulties. Economic struggles limited the scope of some initiatives. Additionally, President Reagan removed the White House solar panels, indicating a retreat from Carter’s vision. But his cutting-edge advocacy inspired subsequent efforts on climate change and conservation.

Jimmy Carter’s environmental legacy serves as a reminder that fearlessness and long-term vision are important in addressing today’s ecological challenges. His leadership continues to inspire. Ultimately, his efforts underscore the mutuality of protecting the environment, sustainable development, and social justice.

CONTACTS: The Carter Center, https://www.cartercenter.org; Jimmy Carter Presidential Library & Museum, https://www.jimmycarterlibrary.gov.

Dear EarthTalk: Why are some people in the green building industry so bullish on bamboo? -- Tim Carey, Puyallup, WA

Bamboo, one of the fastest-growing plants on the planet, is well-known as a rudimentary building material used for many centuries. Today, although the resource is often limited to scaffolding or remote housing projects, advocates have recently rallied for its usage in modern construction. To combat growing greenhouse gas emissions in this industry, bamboo can become an alternative to traditional building materials, mitigating climate change with both economic benefits and sustainable qualities.

Contrary to popular belief, bamboo is a type of grass, not a tree, so it has a unique advantage as timber. While trees typically die after wood harvest and take decades to regrow, bamboo stalks can be continually harvested and regenerated without killing the plant, practically turning it into a limitless renewable resource. In addition, bamboo can match the sturdy properties of more resource-intensive substances. It withstands compression forces greater than concrete and has a tensile strength similar to steel.

What makes bamboo so unique is its ability to fight climate change directly. Like most plants, it absorbs carbon dioxide (CO2), the primary greenhouse gas, throughout its life, removing it from the atmosphere and storing it. Researchers at China’s Xihua University note that every cubic meter of bamboo structural components store up to 187 kilograms of CO2 in its entire lifecycle. If harvested and utilized as a material, bamboo can act as a long-lasting vault for emissions.

“It's a great way of taking carbon out of the environment and making sure it doesn't get re-released,” Atelier One engineer Chris Matthews told Dezeen in 2023. “In general, the idea of bio-based materials where we are capturing carbon and locking it up in a building—that has to be the way forward.” Usually, industrially refining timber like tropical hardwood emits CO2 enough to offset the benefits of this carbon bio-capture, making the process carbon neutral. Bamboo, however, is different. Dutch researchers found that the carbon footprint of flattened bamboo (similar uses to tropical hardwood) is a net-negative.

Bamboo isn’t perfect; Matthews admits that it is “prone to fungal and insect attack.” Thus, researchers continue to engineer more effective products such as laminated bamboo, densely glued blocks of bamboo fiber and hybrid materials. Project Drawdown, which provides free climate solutions ideas and guides to facilitate the transition to a carbon-neutral world, sponsors projects to implement bamboo into degraded forestland to help mitigate climate change. Bamboo can become the future of sustainable construction. Bamboo’s renewability and carbon-sequestering abilities make it an ever more valuable building material.

CONTACTS: Designing with Bamboo for Superior Environmental & Human Health Impacts, usgbc.org/education/sessions/designing-bamboo-superior-environmental-human-health-impacts-4919470.

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