Climate Change Cartoons Oct 30 2015

 

 

 

http://energy.gov/articles/turn-your-halloween-pumpkins-power

With the passing of Halloween, millions of pounds of pumpkins have turned from seasonal decorations to trash destined for landfills, adding to more than 254 million tons of municipal solid waste (MSW) produced in the United States every year. This Halloween, think of turning this seasonal waste into energy as a very important “trick” that can have a positive environmental and energy impact. At landfills, MSW decomposes and eventually turns into methane—a harmful greenhouse gas that plays a part in climate change, with more than 20 times the warming effect of carbon dioxide (CO₂). However, when MSW is used to harness bioenergy—rather than simply being thrown away—the end result benefits the environment and helps our nation become less dependent on carbon-based fuel. Harnessing the potential of bioenergy allows the United States to generate its own supply of clean energy that reduces greenhouse gas emissions. It also limits stress on landfills by reducing waste and could ultimately create jobs for manufacturing, installing, and maintaining energy systems. The Energy Department’s Bioenergy Technologies Office is working together with industry to develop and test integrated biorefineries—facilities capable of efficiently converting plant and waste material into affordable biofuels, biopower and other products. These projects are located around the country and use a variety of materials as feedstocks….

 

 

 

Climate-Smart Restoration: Levee breach transforms 1000 acres of Sears Point farmland back into wetlands

Levee breach transforms [1000 acres of] Sears Point farmland back into wetlands

BY DEREK MOORE AND DIANE PETERSON THE PRESS DEMOCRAT

October 25, 2015, 6:37PM

Cooled by a stiff breeze off San Pablo Bay, about 300 supporters and partners of the Sonoma Land Trust cheered on Sunday as an excavator’s crane broke through a 140-year-old Sears Point levee, allowing saltwater to flood back over 1,000 acres of reclaimed oat hay fields at the southern tip of Sonoma County. As the water rushed in, the crowd of government officials and others involved in the decade-old Sears Point Restoration Project threw balls of pickleweed seeds into the mud to aid the wetland’s rebirth. It is expected to take another 25 to 30 years before the marshland’s vegetation and wildlife comes back completely, but a flock of sandpipers swept in Sunday to investigate the small levee breach, which will be widened to 285 feet. “Historically, over a quarter of the bay’s estuarine habitat was up here at the north end of the bay,” said Don Brubaker, the National Wildlife Refuge manager for the U.S. Fish and Wildlife Service, one of about two dozen partners in the project. “We’re going to see ducks coming in, and wading birds like herons and egrets … eventually, salmon could move in here.” About 1,000 members of the public were expected at a tour of the levee site later Sunday. The morning breach was just the start of the work planned this week by the Sonoma County Land Trust, which plans to lower about a mile of the old levee and cut another 285-foot breach along Tolay Creek.
During the past three years, the Sonoma County Land Trust has excavated a channel for the tidal water to enter the field and used the soil to build a new levee protecting the railroad tracks about a mile to the north, which will become the new northern edge of San Pablo Bay. Public access to the site is expected in early 2016, once safety measures at a railroad crossing are added. Sunday’s celebration started at 10:30 a.m. with a festive brunch and a string of speakers from various organizations and government, including Congressman Mike Thompson, D-St. Helena; state Sen. Lois Wolk, D-Solano; Assemblyman Bill Dodd, D-Napa; and Sonoma County Supervisor David Rabbitt.

Officials praised the restoration project’s many benefits, saying it will lessen the impact of rising sea levels, protect against floods, filter runoff pollution and attract wildlife.
“We are putting a big down payment toward our sea-level-rise insurance policy,” said Jared Blumenfeld, the southwest regional administrator for the Environmental Protection Agency. “I have spent a lot of time trying to make levees bigger and stronger, so this is ironic,” Wolk said. “But what we learned with (Hurricane) Katrina is that when the Mississippi Delta was eliminated, that created more of a problem when the sea rose.”

….The project adds nearly 1,000 acres toward a goal first established by the scientific community in 1999 of restoring 100,000 acres of wetlands in the Bay Area. About 45,000 acres have been restored to date, according to Save the Bay.

Meisler, with the land trust, confessed Friday that he had major doubts whether the tidal restoration would ever be realized. Perhaps the greatest hurdle was finding money for the project. The land trust raised $20 million to acquire the property in 2005 and raised another $18 million for the restoration work. Major donors included the state Wildlife Conservation Board ($5 million), California Coastal Conservancy ($3.2 million) and the Environmental Protection Agency ($2.5 million). There also have been many technical challenges with the project. To raise the farmland by about 7 feet, project managers are relying on the natural process of allowing tides to carry sediment into the area versus the standard — and more expensive — practice of trucking dirt in. The natural approach has never been tried before on a project of this size. Crews added more than 500 small islands to support marsh plants, act as wind breaks and filter out sediment from the incoming tides.

Standing in the dry basin Friday, his boots caked in dirt, Meisler acknowledged not knowing what would happen once water began flowing in. Asked to describe what it would look like in 30 years at the spot where he stood, he replied, “at least six feet under water and covered with pickleweed.”

 

Observers watch the levee being breached Sunday at Sears Point Ranch near Highway 37. A 1,000-acre tidal basin was created for the marsh restoration project. (Frankie Frost/Marin Independent Journal)

San Pablo Bay tidal basin flooded for marsh restoration project

By Janis Mara, Marin Independent Journal Posted: 10/25/15, 9:04 PM PDT | Updated: 1 hr ago

The long arm of the excavator scooped up a load of mud from the levee, and as onlookers gasped, the waters of San Pablo Bay flooded the tidal marsh basin Sunday at Sears Point Ranch in Sonoma County. The moment was the product of 10 years of planning and $18 million in funds, plus tireless work on the part of lead agency Sonoma Land Trust and more than a dozen governmental and advocacy groups. “The restoration of tidal flows is incredibly important,” state Sen. Lois Wolk, D-Davis, told a group of about 300 activists and dignitaries who watched the levee breaching at noon. Nearly 1,000 members of the public signed up to watch the water flowing into the recently constructed 1,000-acre tidal marsh basin off Reclamation Road near Highway 37 at 2 p.m. “(The tidal basin) will be the first line of defense against rising sea levels and the intense storms we know are to come,” Wolk said. “The delta and its survival are part of our national heritage and we must protect it,” Wolk said. “Fresh water mixes with the salty Pacific Ocean and this is what makes this ecosystem special. All species depend on tides and wetlands.”
The project is one of several restoring thousands of acres of marshland around the bay….The levee at Novato’s former Hamilton Field was breached in April 2014, unleashing the bay’s waters into the 648-acre area. That $200 million project will help restore the habitat for the California clapper rail, the salt marsh harvest mouse, fish and tidal plants. “It’s a thrill to be out here today to see the breach happening,” said Roger Leventhal, a senior engineer with Marin County. He was previously a design engineer for the preliminary design for the Sears Point Ranch project. “If you look at what happened at Hamilton and will hopefully happen in Novato, we will have a string of wetlands all the way from China Camp all the way around up to the Napa River,” Leventhal said. The next step in the Bay Area-wide plan is restoration of 1,850 acres north of Hamilton, including a large part of Bel Marin Keys….. “Today we are seeing what is the beginning of a new segment of the trail, two and a half miles,” said planner Maureen Gaffney of the San Francisco Bay Trail project. “This will connect to an existing one that is one and a half miles away at Sonoma Baylands, and will eventually make a ring around the entire San Francisco Bay.” Gaffney added, “The access for hiking and biking and wildlife viewing is amazing.”…

ZERO WASTE IS A LOCAL SOLUTION TO CLIMATE CHANGE

ZERO WASTE IS A LOCAL SOLUTION TO CLIMATE CHANGE

We use a LOT of energy…to heat our homes, to transport ourselves, and to make stuff. Energy went into making the computer you’re using right now, the clothes you’re wearing, the food you ate for breakfast, and pretty much everything you’ve ever bought, used, or thrown away. All that energy emits a lot of greenhouse gases (GHG), contributing to our climate problem. We hear a lot about changing our energy systems to tackle climate change, how energy and transportation are the two biggest culprits — the smokestacks and the tailpipes. But if a lot of those smokestack and tailpipe emissions come from making all our stuff, shouldn’t we be talking about HOW our stuff is made, too?

Smokestacks, Tailpipes and Trash Cans

More than 40% of our climate impact in the U.S. comes from our stuff and our food — how we make it, haul it, use it and throw it away. It’s called our consumption emissions. The more we buy and throw away stuff, the more energy it takes to make new stuff, and the faster climate change accelerates. Zero Waste addresses the entire system of our stuff and can substantially reduce climate emissions by changing what and how much we buy, what resources went into making it, how long it’s designed to last, how much gets reused, recycled or composted, and what we throw away. Zero Waste is one of the fastest, easiest, most cost-effective short-term climate solutions We need time to solve our long-term energy and transportation problems. Zero Waste strategies can be implemented TODAY, using existing technologies and proven programs, and produce immediate results. Zero Waste can help buy us some time to develop more complex energy and transportation solutions.

By 2030, Zero Waste strategies could reduce GHG emissions by more than 400 million metric tons CO₂ per year, the equivalent of taking more than 20% of U.S. coal-fired powered plants off the grid. This means Zero Waste offers greater annual GHG savings than expanding nuclear power, significantly improving vehicle efficiency, carbon capture projects, and many other prominent climate strategies. Zero Waste strategies are also cost-effective climate solutions. ICLEI calls out recycling and composting as some of the most cost-effective actions local governments can take to reduce community GHG emissions. Communities around the world are investing in Zero Waste as a priority climate action. One of California’s first actions in its landmark climate change policy was to require businesses and apartments to recycle, a move that will reduce GHG emissions by five million metric tons….

Leading experts support Zero Waste as a climate solution:

“Recycling is already making a major contribution to keeping down emissions. Indeed, its scale is so little appreciated that it might be described as one of the ‘best kept secrets’ in energy and climate change…”

-Renowned Economist Lord Nicholas Stern, Blueprint for a Safer Planet

 

 
 

Fact Check: Reign of Recycling

The New York Times (NYT Opinion) printed an opinion piece by John Tierney (@JohnTierneyNYC) that astounded us by the sheer number of inaccurate statements and misrepresentations about the economic and environmental impact of the recycling industry. We thought it would be helpful to point a bunch of them out and share third-party, verifiable sources.

Drought-driven salmon deaths could have far-reaching impact

Drought-driven salmon deaths could have far-reaching impact

Drought-driven salmon deaths could have far-reaching impact

By Peter Fimrite SF Chronicle Updated 7:46 am, Thursday, October 29, 2015

One of the last wild runs of chinook salmon in California is sinking fast amid the four-year drought and now appears perilously close to oblivion after the federal agency in charge of protecting marine life documented the death of millions of young fish and eggs in the Sacramento River. The National Marine Fisheries Service reported Wednesday that 95 percent of the winter-run chinook eggs, hatchlings and juvenile salmon died this year in the river, which was too warm to support them despite conservation efforts. It was the second year in a row that most of the juvenile salmon died in the soupy water released from Shasta Dam, failing to make it to the ocean. The situation could have far-reaching effects, leading to cuts in water allotments to farmers next year if projected rains and a strong snowpack don’t erase drought deficits this winter. Commercial and recreational fishing limits could be imposed to protect the endangered chinook population, taking a toll on those industries. “Certainly there is cause for alarm when we are talking about 95 percent mortality,” said Garwin Yip, the branch chief for water operations and delta consultations for the fisheries service. “We think it is temperature-related.”

The problem was caused by a lack of snow this year on top of four years of drought. The U.S. Bureau of Reclamation, Yip said, was left without enough cold water behind Shasta Dam to release during spawning season. Chinook, also known as king salmon, are born in the Sacramento River and pass through San Francisco Bay. They roam the Pacific Ocean as far away as Alaska before returning three years later to spawn. There are three distinct runs of salmon — winter, spring and late fall, which is what West Coast fishers catch in the ocean. The winter and spring-run chinook salmon are listed under the state and federal endangered species acts. The winter run has been endangered since 1994. The fisheries service worked with two state agencies, the Department of Water Resources and the Department of Fish and Wildlife, to develop an elaborate plan this year to regulate cold-water releases from Shasta Dam.

Resource officials are required by law to release enough cold water to keep the Sacramento River at 56 degrees — the ideal temperature for fish. In a bid to meet that requirement, federal officials sharply limited flows and delayed water deliveries to hundreds of Central Valley farmers.

Failed plan

The problem, Yip said, was that “there wasn’t as much cold water as anticipated and the water wasn’t as cold as we thought it was going to be.” The lack of cold water forced regulators to come up with a new temperature management plan, this one allowing the water to warm up to 57 degrees. But it didn’t work, and water temperatures, at times, rose to 58 degrees, he said. As a result, the number of juvenile fish counted this month at the Red Bluff diversion dam, downstream of Shasta, was down 22 percent compared with last year, which was also a bad year. That’s despite the fact that there were 21 percent more adult fish laying eggs in the river, Yip said. Two months remain in this year’s run, but

Elevated CO2 Levels Directly Affect Human Cognition, New Harvard Study Shows

CREDIT: Climate Interactive The world had been on a path toward 900 ppm of CO2 in the air by 2100. Commitments made by major countries to cut or constrain CO2 emissions through 2030 — Intended Nationally Determined Contributions (INDCs) — would put us on a sharply lower trajectory. To avoid catastrophic impacts, however, we will need much stronger commitments post-2030.

Elevated CO2 Levels Directly Affect Human Cognition, New Harvard Study Shows

by Joe Romm Oct 26, 2015 10:05am

In a landmark public health finding, a new study from the Harvard School of Public Health finds that carbon dioxide (CO2) has a direct and negative impact on human cognition and decision-making. These impacts have been observed at CO2 levels that most Americans — and their children — are routinely exposed to today inside classrooms, offices, homes, planes, and cars. Carbon dioxide levels are inevitably higher indoors than the baseline set by the outdoor air used for ventilation, a baseline that is rising at an accelerating rate thanks to human activity, especially the burning of fossil fuels. So this seminal research has equally great importance for climate policy, providing an entirely new public health impetus for keeping global CO2 levels as low as possible. In a series of articles, I will examine the implications for public health both today (indoors) as well as in the future (indoors and out) due to rising CO2 levels. This series is the result of a year-long investigation for Climate Progress and my new Oxford University Press book coming out next week, “Climate Change: What Everyone Needs to Know.” This investigative report is built on dozens of studies and literature reviews as well as exclusive interviews with many of the world’s leading experts in public health and indoor air quality, including authors of both studies.

What scientists have discovered about the impact of elevated carbon dioxide levels on the brain

Significantly, the Harvard study confirms the findings of a little-publicized 2012 Lawrence Berkeley National Laboratory (LBNL) study, “Is CO2 an Indoor Pollutant? Direct Effects of Low-to-Moderate CO2 Concentrations on Human Decision-Making Performance.” That study found “statistically significant and meaningful reductions in decision-making performance” in test subjects as CO2 levels rose from a baseline of 600 parts per million (ppm) to 1000 ppm and 2500 ppm.

…The impact of fossil fuels and modern buildings on human cognition

GREENLAND IS MELTING AWAY

This river is one of a network of thousands at the front line of climate change

GREENLAND IS MELTING AWAY

October 27, 2015 NY TIMES

By Coral Davenport, Josh Haner, Larry Buchanan and Derek Watkins

On the Greenland Ice Sheet — The midnight sun still gleamed at 1 a.m. across the brilliant expanse of the Greenland ice sheet. Brandon Overstreet, a doctoral candidate in hydrology at the University of Wyoming, picked his way across the frozen landscape, clipped his climbing harness to an anchor in the ice and crept toward the edge of a river that rushed downstream toward an enormous sinkhole. If he fell in, “the death rate is 100 percent,” said Mr. Overstreet’s friend and fellow researcher, Lincoln Pitcher. But Mr. Overstreet’s task, to collect critical data from the river, is essential to understanding one of the most consequential impacts of global warming. The scientific data he and a team of six other researchers collect here could yield groundbreaking information on the rate at which the melting of Greenland ice sheet, one of the biggest and fastest-melting chunks of ice on Earth, will drive up sea levels in the coming decades. The full melting of Greenland’s ice sheet could increase sea levels by about 20 feet. “We scientists love to sit at our computers and use climate models to make those predictions,” said Laurence C. Smith, head of the geography department at the University of California, Los Angeles, and the leader of the team that worked in Greenland this summer. “But to really know what’s happening, that kind of understanding can only come about through empirical measurements in the field.” For years, scientists have studied the impact of the planet’s warming on the Greenland and Antarctic ice sheets. But while researchers have satellite images to track the icebergs that break off, and have created models to simulate the thawing, they have little on-the-ground information and so have trouble predicting precisely how fast sea levels will rise…The scientists were excited but anxious as they prepared to travel inland by helicopter to do the fieldwork at the heart of their research: For 72 hours, every hour on the hour, they would stand watch by a supraglacial watershed, taking measurements — velocity, volume, temperature and depth — from the icy bank of the rushing river.

“No one has ever collected a data set like this,” Asa Rennermalm, a professor of geography at the Rutgers University Climate Institute who was running the project with Dr. Smith, told the team over a lunch of musk ox burgers at the Kangerlussuaq airport cafeteria. Taking each measurement was so difficult and dangerous that it would require two scientists at a time, she said. They would have to plan a sleep schedule to ensure that a group was always awake to do the job. Everyone knew the team would be working just upriver from the moulin — the sinkhole that would sweep anyone who fell into it deep into the ice sheet. ….They might even learn, Dr. Smith said, that the water is refreezing within the ice sheet and that sea levels are actually rising more slowly than models project. For three days and three nights, the scientists continued to measure the river, as up to 430,000 gallons of water a minute poured off the ice and into the moulin. On the final morning, the team, tired but elated, gathered by the river as the boogie board made its final trip. By then, Mr. Ryan’s backup drone had safely completed its mapping mission. Mr. Overstreet broke open a celebratory bag of dried mangoes — a lavish treat for the ice campers.

HFCs- Worst Climate Threat, Stronger Than CO2

HFCs- Worst Climate Threat You Never Heard of Is Stronger Than CO2

Alex Nussbaum
anussbaum1

October 29, 2015 — 5:00 PM PDT Updated on October 30, 2015 — 7:44 AM PDT

• HFCs are thousands of times stronger than CO2 at trapping heat
  
• As envoys debate a phase-out, some countries balk at cost
  

The biggest global warming battle you’ve never heard of kicks off in Dubai this weekend. Climate negotiators from across the globe will gather in the Persian Gulf city to debate how to get rid of hydrofluorocarbons — a class of hundreds of artificial chemicals used in refrigerators, air-conditioners, fire suppressants and other widely used products. While less common than greenhouse gases like carbon dioxide or methane, HFCs can be thousands of times more potent, pound for pound, at heating up the planet. They’re also gaining in popularity as demand for air conditioning, refrigeration and other services is expected to soar in developing countries in coming decades. The result: HFCs are now the world’s fastest growing greenhouse gases and projected to rise even more in the future. A worldwide agreement coming out of the United Nations-run meeting in Dubai to quickly get rid of HFCs may keep the equivalent of 100 billion tons of CO2 out of the atmosphere by 2050 and avoid a half-degree Celsius of warming by century’s end, proponents say. That’s about a quarter of the 2-degrees Celsius (3.6-degree Fahrenheit) limit that scientists say is needed to avoid the worst effects of climate change. “If we can avoid 100 billion tons and eliminate a half-degree of warming, that’s a pretty good down payment,” said Durwood Zaelke, president of the Washington-based Institute for Governance & Sustainable Development. A global deal is proving elusive, however. Poorer countries and those in warmer climates have concerns about the reliability and expense of substitutes, which can cost ten times as much as the climate-threatening chemicals they replace. Advocates fear a new ban may boost the black market for HFCs. Chemical makers including Chemours Co. have found a significant amount of the refrigerants in use in some regions are labeled as the newer, safer products, but are actually older, cheaper products harmful to the environment. “The chemical industry is producing literally hundreds of different kinds of HFC blends,” said Clare Perry, a senior campaigner for the Environmental Investigations Agency, a nonprofit that tracks environmental crime. “The scope for illegal trade is just enormous.”….

Marine reserves will need stepping stones to help fish disperse between them

 

http://www.ecology.com/2012/11/13/marine-reserves-make-fish-naive/

Marine reserves will need stepping stones to help fish disperse between them

Posted: 27 Oct 2015 10:29 AM PDT

A massive field effort on the Belizean Barrier Reef has revealed for the first time that the offspring of at least one coral reef fish, a neon goby, do not disperse far from their parents. The results indicate that if marine protected areas aim to conserve such fishes, and biodiversity more broadly, then they must be spaced closely enough to allow larvae to disperse successfully between them.
A growing body of scientific research has demonstrated that marine protected areas, particularly no-take marine reserves that exclude extractive activities like fishing, can increase biodiversity and sustain fisheries within the reserves, often with spillover benefits in surrounding areas. But despite the decline of coral reefs and fisheries worldwide, only 3.5 percent of the ocean is protected and only 1.6 percent of it is fully protected. Moreover, for reserves to conserve marine biodiversity most effectively, they must be embedded in networks that are connected such that marine life from one reserve can repopulate other reserves. “Before our study, we didn’t have a deep, quantitative understanding of how far fish larvae do and do not disperse from their parents,” says study co-author Peter Buston of Boston University. “If we’re going to design effective networks of marine reserves, we need to know how far baby fish can and cannot travel. Our study suggests that for fishes like the neon gobies, protected areas may need to be close together.”…

 

Cassidy C. D’Aloia, Steven M. Bogdanowicz, Robin K. Francis, John E. Majoris, Richard G. Harrison, Peter M. Buston. Patterns, causes, and consequences of marine larval dispersal. Proceedings of the National Academy of Sciences, 2015; 201513754 DOI: 10.1073/pnas.1513754112

Rewilding the future

Rewilding the future

Posted: 27 Oct 2015 06:52 AM PDT

New research shows that the loss of large animals has had strong effects on ecosystem functions, and that reintroducing large animal faunas may restore biodiverse ecosystems. Rewilding is gaining a lot of interest as an alternative conservation and land management approach in recent years, but remains controversial. It is increasingly clear that Earth harbored rich faunas of large animals — such as elephants, wild horses and big cats — pretty much everywhere, but that these have starkly declined with the spread of humans across the world — a decline that continues in many areas. A range of studies now show that these losses have had strong effects on ecosystem functions, and a prominent strain of rewilding, trophic rewilding, focuses on restoring large animal faunas and their top-down food-web effects to promote self-regulating biodiverse ecosystems. A new study led by researchers from Department of Bioscience, Aarhus University, published in PNAS today, synthesizes the current scientific research on trophic rewilding and outlines key research priorities for rewilding science. “Reviewing the evidence from major rewilding projects such as the wolf reintroduction to the Yellowstone National Park and the Oostvaardersplassen experiment in the Netherlands, the study concludes that species reintroductions and ecological replacements can successfully restore lost food-web cascades with strong ecological effects,” says lead author Professor Jens-Christian Svenning, Department of Bioscience, Aarhus University.

 

Jens-Christian Svenning, Pil B. M. Pedersen, C. Josh Donlan, Rasmus Ejrnæs, Søren Faurby, Mauro Galetti, Dennis M. Hansen, Brody Sandel, Christopher J. Sandom, John W. Terborgh, Frans W. M. Vera. Science for a wilder Anthropocene: Synthesis and future directions for trophic rewilding research. Proceedings of the National Academy of Sciences, 2015; 201502556 DOI: 10.1073/pnas.1502556112

Scientists’ warning: Extinction of big land animals forever alters environment

 

In this photo taken on Thursday, Oct. 1, 2015, an elephant crosses the road in Hwange National Park, about 700 kilometers south west of Harare, Zimbabwe. Cyanide poisoning has killed 22 elephants in Zimbabwe. Photo: Tsvangirayi Mukwazhi, Associated Press

Scientists’ warning: Extinction of big land animals forever alters environment

By Peter Fimrite Updated 3:03 pm, Monday, October 26, 2015 SF Chronicle

Extinctions of large animals — a fate that could soon befall elephants and rhinoceros — have a cascade effect on local ecosystems, including Northern California, where many smaller animals and plants died off after mammoths were wiped out, a team of scientists has discovered. The size of elephants, wildebeest and other big plant-eaters not only makes them impressive and fascinating, but vital to the many species, including flora and fauna, that live with and depend on them, according to a joint report by UC Berkeley, Stanford University, California State University Sacramento and the University of Chile. “Ecological studies have shown that if you pull out a top predator or a key herbivore today, you get dramatic change in the ecosystem,” said Anthony Barnosky, a UC Berkeley professor of integrative biology and the study leader. “Our study makes it clear that in the past, such changes have lasted for thousands of years. These extinctions really do permanently change the dynamics. You can’t go back.” The study, which was released Monday and is to be published in the journal Proceedings of the National Academy of Sciences, looked at past extinctions in North and South America since humans arrived about 15,000 years ago. The scientists found that the number and diversity of small animals and vegetation decreased all along the Pacific Northwest, as well as the western and northeastern United States, after mammoth and mastodon extinctions. In Alaska and the Yukon, what was once a mix of forest and grassland became mostly tundra after the loss of mammoths, native horses and other large animals, according to the study….