increases

The American butterfly census

April 15, 2025 By EarthWise Leave a Comment

There has been a great deal of interest in the plight of monarch butterflies in this country. Monarchs’ population and migratory habits are closely watched, and many people have been planting milkweed in their gardens to help their caterpillars. But other butterfly species have received much less attention despite the fact that many butterfly populations are in decline.

A groundbreaking new study has provided comprehensive answers about the status of butterflies in America. Over the past 20 years, the contiguous US has lost 22 percent of its butterflies.

The study is based on over 12 million individual butteries counted in 77,000 surveys across 35 monitoring programs from 2000 to 2020. Three hundred forty-two butterfly species in total were analyzed. Thirty three percent showed statistically significant declines while less than 3% displayed statistically significant increases. Overall, 13 times as many species decreased as increased.

Why are butterfly populations crashing? Experts point to a combination of factors: habitat loss as land in converted for agriculture or development, climate change, and pesticide use. It is not clear which factor is most important and may well vary by location. Pesticide use – especially neonicotinoids – has been shown to play a particularly lethal role in studies.

Insects including butterflies play a huge role in supporting life on earth. They pollinate plants, feed birds and many other creatures in the food web. Nature collapses without them. And butterflies are clearly in trouble.

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See How Butterflies Are Surviving, or Not, Near You

Photo, posted August 9, 2016, courtesy of Rachel Larue/Arlington National Cemetery via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Rats and climate change

March 10, 2025 By EarthWise Leave a Comment

Human activity has made rats one of the most prolific mammals on the planet. Our waste, buildings, and ships provide food, shelter, and transport. In the United States alone, rats cost the country approximately $27 billion each year in damage to infrastructure, crops, and contaminated food supplies. Additionally, rats carry and spread over 50 zoonotic pathogens and parasites, impacting public health around the world.

Now, climate change is adding to the problem. According to a new study recently published in the journal Science Advances, urban rat populations are exploding as global temperatures rise. The researchers found that Washington DC, San Francisco, Toronto, New York City, and Amsterdam had the greatest population increases. In fact, over the past decade, rats increased by a whopping 390% in Washington DC, 300% in San Francisco, 186% in Toronto, and 162% in New York City. The study, which examined data from 16 cities globally, found that 11 of them showed significant increases in rat numbers.

Only Tokyo, Louisville, and New Orleans bucked the trend with declining rat numbers.

According to the researchers, the best pest management strategies involve making the urban environment less rat-friendly as opposed to removing rodents that are already there. An example would be putting trash in containers instead of bags on the street.

There aren’t many perks to the changing climate – unless, of course, you’re a rat.

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Increasing rat numbers in cities are linked to climate warming, urbanization, and human population

‘Perfect rat storm’: urban rodent numbers soar as the climate heats, study finds

Photo, posted September 25, 2018, courtesy of Tim Felce via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Pollinator-friendly solar power

February 16, 2024 By EarthWise Leave a Comment

Global insect biodiversity has been in decline as a result of habitat loss, pesticide use, and climate change. Restoring insect habitat is a way to reverse that trend. Expanded use of solar energy is a critical part of mitigating climate change. In order to meet the grid decarbonization goals the U.S. has set, approximately 10 million acres of land will be needed for large-scale solar development. According to a new study by Argonne National Laboratory and the National Renewable Energy Laboratory, these two efforts are complementary.

Disturbed lands such as former agricultural fields are ideal locations to install solar panels. These lands can also be established as excellent habitats for insect pollinators and other wildlife that provide important ecosystem services.

A five-year study looked at two solar sites in southern Minnesota that were built on retired agricultural land. The sites were planted with native grasses and flowering plants in early 2018. Over a five-year period, the researchers conducted hundreds of observational surveys for flowering vegetation and insect communities, evaluating changes in plant and insect abundance and diversity.

The team observed increases for all habitat and biodiversity metrics. The total insect abundance tripled, while native bees showed a 20-fold increase in numbers.

The research highlights the relatively rapid insect community responses to habitat restoration at solar energy sites. If properly sited, the solar sites can offset the losses of natural areas created by solar farms and actually make prime farmland more productive through the pollination services provided by habitat-friendly solar energy.

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Insect populations flourish in the restored habitats of solar energy facilities

Photo, posted February 28, 2014, courtesy of Tom Koerner/USFWS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Greenhouse Gases Continue To Rise | Earth Wise

May 24, 2023 By EarthWise Leave a Comment

Despite all the focus on reducing emissions of greenhouse gases, there continues to be little progress toward actually accomplishing reductions. A combination of growing populations, increasing industrialization in the developing world, and just plain reluctance on the part of many sectors of society to act, have all contributed to the continuing buildup of climate-altering gases in the atmosphere.

Levels of carbon dioxide, methane, and nitrous oxide – the three greenhouse gases produced by human activity that are the major contributors to climate change – all continued historically high rates of growth in 2022.

CO2 levels rose by 2.13 parts per million last year, roughly the same rate observed during the past decade. The current level of 417 ppm is 50% higher than pre-industrial levels. Increases of more than 2 ppm have occurred for 11 consecutive years. Prior to 2013, there had never even been 3 years in row with increases of that size.

Methane levels increased by 14 parts per billion, the fourth largest increase over the past 40 years. Methane levels in the atmosphere are now two-and-a-half times greater than their pre-industrial level.

The third most significant greenhouse gas – nitrous oxide – also saw a large increase, reaching 24% above pre-industrial levels.

Carbon dioxide emissions are by far the most important contributor to climate change and the continuing widespread burning of fossil fuels is the primary source. There are widespread intentions to reduce carbon dioxide emissions, but those intentions have not yet resulted in sufficient actions.

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Greenhouse gases continued to increase rapidly in 2022

Photo, posted May 16, 2014, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio