Bruce Melton :
Yosemite National Park: Climate Change is here, and it’s bad

We are documenting what no others are documenting.

Yosemite National Park, El Capitan, and bark beetle kill. Photo by Bruce Melton / The Rag Blog.

By Bruce Melton | The Rag Blog | July 31, 2019

Bruce Melton will discuss his recent environmental expedition to Yosemite National Park at Thorne Dreyer’s 74th Birthday Bash, a benefit for the New Journalism Project which takes place this Thursday, August 1, 6-9:30 p.m., at The High Road on Dawson. Bruce and his Climate Change Band will perform at the event, as will jazz singer Sarah Sharp.

As of 2017, 2.4 million trees have been killed by bark beetles in Yosemite National Park.

Some say it’s a natural occurrence, and it is. It happens every time our climate changes abruptly.

This story is a part of Climate Change Across America, an epic filmmaking effort to document the ongoing extreme impacts of climate change already happening across North America. This is our fifth year of production and we have driven 52,500 miles in our quest so far, from Brownsville to the North Slope of Alaska, short on money, camping almost always. (See Beach Report 2019, 2018 Photo Tour, 2018 Trip Log, 2018 Instagram, Permafrost 2018, Beach Report 2017, The Desert 2017, The Beetles 2016, and more at

We are documenting what no others are documenting: sea level rise beach erosion that has already eroded away much of our wild barrier island beaches; unprecedented beetle-killed forests across North America from a native bark beetle; permafrost melt that has caused Alaska to flip from a carbon sink to a carbon source; flooding that has increased to the million-year storm intensity with Hurricane Harvey; and the 14,000 catastrophes in one day when a climate change-maddened wildfire swept through Paradise California.

What we are documenting is remarkable in that, when it makes the media it is often portrayed as being “natural cycles.” This is an explanation that sounds good, but it simply is not good sound science. The perceived debate has taken its toll and our country’s most precious resources are imperiled and currently in various states of egregious collapse. This installment of our story is about climate change in Yosemite National Park. (See our Instagram videos from 2019 here.)

2.4 million mature trees have been killed by native bark beetles inside the park.

Yosemite National Park, California, July 2019: 2.4 million mature trees have been killed by native bark beetles inside the park. The beetles have overpopulated as winter temperatures have risen and the summer beetle breeding season has lengthened. Real drought and perceived drought, where warmer temperatures create more evaporation even with normal rainfall, has caused trees to create less sap, which is the main method that trees use to repel bark beetle attacks.

Across North America, 96 million acres of forest have been mostly killed by bark beetles since the turn of the century. This area is the size of New England, New York, and New Jersey combined, dwarfing any previous known attack. The kill in California peaked in the mid-twenty teens with their worst drought ever recorded.

The culprit is a tiny grain of rice-sized native bark beetle driven berserk because of warming. The beetles thrive on drought-stressed trees and create astonishing attacks that can kill 95 percent of the trees in a forest. The attack in Yosemite hasn’t been this extreme, but it remains ongoing and even the best-case warming target of 1.5 C allows triple the warming that allowed this global beetle pandemic to begin.

The beetles in Yosemite are active between about 3,000 and 4,500 feet in elevation, on about 18 percent of the total park area of 748,000 acres. Badly impacted is the central Yosemite Valley.
The National Park Service is cutting 5,000 trees per year to help keep campers safe and for good reason. A wood fungus accompanies the beetle making the dead wood extremely brittle, greatly enhancing the risk of visitor injury if the dead trees are not promptly cut in popular areas.

Who knows that our national treasures are collapsing?

But who sees it? Who knows that our national treasures are collapsing? The media certainly isn’t dwelling on it. Part of the reason is that the dead trees literally disappear back into the forest. Their dead sticks are only about 10 percent as visible as when they were leaved. And besides, dead trees are just a normal part of the forest, right?

It’s hard to see unless you are looking. I ask tourists all the time, “What do you think about all the dead trees?” They respond with, “Oh yeah, what do you call those pretty red pine trees?” Then, in the most visible areas where the most tourists are located, the Park Service cuts down the dead trees quickly to keep from killing tourists.

Like last year in Yosemite, the beetle kill was nowhere near epidemic attack levels after two years of banner winter snow. But new beetle kill persists. Some say it’s from stress because of Smokey Bear fire suppression policy but the facts are that if it were not for warming, and nonlinearly increasing stress from warming, these attacks would be no bigger than they were before the turn of the twenty-first century when climate change warmed beyond natural variation.

Two ponderosas fallen to beetle kill this year despite two banner years of snow in a row. Photo by Bruce Melton / The Rag Blog.

The Sentinel, Half Dome, El Capitan, Bridal Veil, Yosemite Falls… I shot some climbers on El Cap, framed by beetle kill ponderosa in the foreground. Out national treasure should not have to exist with a destroyed forest at their feet, but they do.

National Forests are dying at a rate that is twice as fast as they are growing.

U.S. National Forest Service data now shows that U.S. National Forests, on average, are dying at a rate that is twice as fast as they are growing. Warming to 1.5 C targets will dramatically increase forest mortality, and these forests will not grow back. Not until we not just limit warming to 1.5 C, but until we restore our climate to the evolutionary boundaries where our ecosystems evolved.

One of the park rangers shared a telling story of Yosemite’s largely unseen climate impacts. Thirty years ago the National Park Service rented cross country skis to tourists in Yosemite Valley. It doesn’t snow enough in Yosemite Valley any longer and they have stopped renting cross country skis.

Please help us get this story out. Our national treasures and treasures across the world are at grave risk. We must change the rhetoric in our climate change culture from one of dangerous climate change avoidance with 1.5 C, to climate restoration where we restore our climate to the temperature range where our global ecologies evolved, where these unprecedented climate change impacts cease.


Yosemite National Park beetle attack conditions…
Tree Mortality Can Cause Hazardous Conditions, Yosemite National Park, July 26, 2017

North America beetle attack conditions…
Base document: Katz, Small Pests, Big Problems: The Global Spread of Bark Beetles, Yale Environment 360, September 21, 2017.

U.S. 2017: 85,000 square miles (54.4 million acres) in the Western U.S.

Canada 2012: 65,000 square miles (41.6 million acres) in Canada. An area the size of New England, New York and New Jersey combined.
Richards, Beetles Warm BC Forests, The Scientist, November 2012.

Our climate warmed beyond natural variation about 2000… This is really when climate change became real, when our climate statistically warmed more than what can be expected as with normal variation in weather. In general, temperature extremes began emerging from natural variation in some parts of the world about 1980, and will conclude across most parts of the world by 2020. Therefore the average time of anthropogenic emergence is about 2000.
King et al., The timing of anthropogenic emergence in simulated climate extremes, Environmental Research Letters, September 10, 2015.

Forest mortality exceeds growth for the first time… US National Forests are dying at a rate that is twice what they are growing.
Forest Mortality Exceeds Growth In America’s National Forests, Forest2Markets, May 31, 2018.
Data: Forest Resources of the United States, 2017: A technical document supporting the Forest Service 2020 Resource Planning Act (RPA) Assessment.

[Bruce Melton, a longtime contributor to The Rag Blog and guest on Rag Radio, is a professional engineer, environmental researcher, filmmaker, author and CEO of the Climate Change Now Initiative in Austin, Texas; the oldest, independent climate science education organization in the world founded in 2005. The Climate Change Now Initiative is a nonprofit outreach organization reporting the latest discoveries in climate science in plain English, using global warming psychology to communicate this new science on the right side of the brain. The Initiative’s science reporting, films, music and images of climate impacts happening now can be found at]

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2 Responses to Bruce Melton :
Yosemite National Park: Climate Change is here, and it’s bad

  1. Paul Spencer says:

    Bruce – Your report is mostly correct in its cause analysis, but here are a few additional pieces of information. First, most of the damage is done by a particular pine bark beetle and the particular target of these critters is the Lodgepole Pine. The range of this pine tree is fairly narrow in east-west direction and vertically, but it still covers a lot of acres. So the eastern half of the Rockies (e.g., Glacier National Park), the eastern slopes of the Cascade Mountains, and the western slopes of the Sierras are decimated. This is actually a natural cycle for the Lodgepole for as long as we have written observations. Yes, it is ‘way worse than in the past. That leads me to:

    Secondly – the density of these trees – and most other western tree species – is much higher than the historical norm. Part of this is fire suppression over the last 100 years. Part of it is more recent and is due to severe reductions of forest management – timber harvest – by the federal government in their timberlands. (And, yes, the USFS does consider these lands to be Theirs.) Overcrowding has several impacts on the bug epidemic. 1) pine beetles are weak fliers. Having more food nearby is a boost for their population growth. 2) Dense tree stands reduce the groundwater available to each individual tree in the stand, which fits with your concern about water availability. 3) While the trees have canopy, dense stands reduce snowfall to the ground. The snow tends to sublimate back into the atmosphere and is lost for spring ground penetration.

    Thirdly, most of the other conifers are not in epidemic conditions with their own evolved pests. There may be more loss among these other species, but the Ponderosa Pines, the Douglas Firs, the Hemlocks, the Spruce, the Larch, the Cedars, and the true firs are not currently in danger in most places – except for forest fire. You may know that overcrowding and water reduction contribute to that situation, too.

  2. Bruce Melton says:

    Spencer, Sorry I missed this comment. I wonder if this note will make it to you through the magic of the internet… Lodgepole are peculiar trees. They grow to burn, then erupt like hair on a dog if conditions allow. Because of this peculiarity, conflating fire suppression and increased fuels with lodgepole forests is not valid. This relationship works with other species, but because of lodgepole’s peculiar way of regenerating, where they grow back so thick it is impossible to walk through them, it doesn’t work here. The mountain pine beetle (Dendroctonus ponderosae) that is responsible for the demise of almost all large lodgepole forests across the North American West is now in decline – it has eaten all of its favorite trees. But it doesn’t stop there. In the 2000s, D. ponderosae widely attacked not just the lodgepole and ponderosa pine it is named after, but it attacked spruce and fire too. There were so many beetles that there were not enough lodgepole to house them all. In pockets, D. ponderosae is still attacking both lodgepole and ponderosa pine, like in Yosemite and across the Sierra. But now we have greater warming, greater accumulation of stress, and less aggressive bark beetles are swinging the numbers of millions of acres killed back towards peak lodgepole days once again. These beetles are predominantly spruce bark beetles and fir bark beetles and even the often thought of most hardy junipers have their own beetles that are increasing to pandemic numbers.
    The challenges do not stop here. WArming is so great now and stress so large that a third of forests killed by fire since 2000 are not regenerating and half that are are regenerating at only half the rate of the 20th century. What the research says that reports these findings is that the same regeneration failure is likely happening in beetle kill forest too. When you speak of forests that have yet to succumb to the beetles, you are speaking of the West Coast and yes, until recently much of the west Coast was immune. Beetles attack first in drier areas on the edge of evolution. The Rockies are decimated from the Rio Grande to the Arctic Circle because they are drier than much of the West Coast. The Sierra in 2018 and 2019 was in really bad shape and then 2020 and 2021 happened and now the situation is so bad the National Park Service has said sequoias have passed through a tipping point where 13,000 of 75,000 known mature sequoias were killed in fire, mostly in 2020 and 2021, about 75 percent because of warming, 25 percent because of excess fuels. Without record dry fuels, record low humidities, higher temperatures creating easier ignition, unprecedented wind storms and unprecedented nighttime fire behavior, increased fuels would only have resulted in fires like we had before 2010, where fire area burned today has reached levels not recorded since pre-European times and this with $3 billion in fire suppression efforts in 2020 by CalFire alone, not counting USFS, BLM and local expenditures.

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