Public speaks out against Pruitt’s effort to reopen a loophole for super-polluting glider trucks

Public health experts, freight truck manufacturers and truck dealers sent a shared message to Environmental Protection Agency (EPA) Administrator Scott Pruitt at a recent public hearing – don’t reopen a loophole for super-polluting glider trucks.

Glider trucks are new freight trucks that have used engines installed in them. Those older engines emit harmful soot and smog-causing pollutants at rates dramatically higher than trucks that comply with current emission standards.

Glider trucks, with their older engines, emit high levels of pollutants like cancer-causing diesel particulate, as well as oxides of nitrogen and particulate matter – which have been linked to severe human health impacts, including increased asthma attacks and exacerbation of heart disease.

Pruitt has proposed reopening a loophole in our national Clean Truck Standards that would allow glider trucks to pollute without restriction. This proposed rollback of common sense pollution limits is a slap in the face – not only to American families, who deserve clean air to breathe, but also to the heavy duty trucking industry, which has invested in cleaner technologies for years.

Freight truck leaders voice concerns about glider truck loophole

Volvo senior vice president Susan Alt testified at the public hearing that Pruitt’s proposal “makes a mockery” of their responsible investments in pollution control equipment and clean technologies.

Representatives from the American Trucking Associations, the Engine Manufacturers Association, and the Heavy Duty Fuel Efficiency Leadership Group echoed concerns that the proposed rollback would undermine their investment decisions for the past decade, upend the level playing field the industry needs for the well-being of their businesses, and jeopardize the regulatory certainty upon which they rely.

Freight truck dealers underscored that they hire and employ skilled technicians — in communities all across the country — to service and maintain modern, cleaner engines. Their businesses, and their employees, will be at risk if the loophole for glider trucks is reopened.

Pruitt issued his proposal based on flawed, incomplete information

EPA estimated in 2016 that glider truck emissions were as much as 40 times higher than modern engines.

The agency recently undertook more emission testing to refine its data. But Pruitt issued his proposal to repeal the glider provisions before EPA’s testing could be completed.

Instead, Pruitt’s proposal highlights poorly supported assertions from Tennessee Tech University, which conducted testing on glider trucks that found much lower emissions of oxides of nitrogen and particulate matter than EPA’s estimates.

Last week, EPA released its new, updated testing data, as well as a memo with further details about the Tennessee Tech findings that show flaws in the university’s analysis. This new information confirms the serious threat to human health posed by glider trucks.

EPA’s new test data suggests that the estimates it relied on before closing the glider truck in the first place may have been too conservative:

Under highway cruise conditions, [oxides of nitrogen] emissions from the glider vehicles were approximately 43 times as high, and [particulate matter] emissions were approximately 55 times as high as the conventionally manufactured tractors. (emphasis added)

EPA identified a number of deeply troubling flaws and biases in Tennessee Tech’s methodology, facilities, and equipment used to generate their data. Most notably, Tennessee Tech’s assertions that the tested glider trucks met EPA’s 2010 emission standard for particulate matter and performed equally as well as modern trucks were not based on any actual measurement of the pollutant – just visible inspection, a practice abandoned decades ago as wholly inadequate for measuring particulate matter from diesel engines.

Equally alarming, as the Washington Post has reported, the EPA memo acknowledges that Tennessee Tech has a financial relationship with a major glider manufacturer – Fitzgerald Glider Kits – that is pushing for EPA to roll back the pollution protections for its product. The testing facility used by Tennessee Tech is owned by Fitzgerald.

Pruitt puts clean air at risk

These documents reinforce what has been clear since Pruitt took office – the Administrator is ignoring his agency’s own science and expertise, and putting the health of American families at risk, with an onslaught of attacks against vital pollution protections – attacks that are endorsed by politically connected major polluters.

Diverse voices turned out in full force at the public hearing to rebuke the most recent example of this pattern of practice:

  • Terry Dotson of heavy-duty truck dealer Worldwide Equipment Inc. testified that his company could build glider kits, but chose not to because “we choose to do the right thing.”
  • Blanca Iris Verduzco, on behalf of East Yard Communities for Environmental Justice, spoke as a resident of South East Los Angeles, an industrialized community exposed to a lot of freight transportation pollution. She urged EPA to protect her community from health dangers, and not to roll back protections.
  • John Calvin Doub with TMI Truck and Equipment expressed concern for his three grandchildren, and talked about the breathing difficulties caused by air pollution. He cautioned EPA that until you have witnessed a child having an asthma attack, you don’t understand the full impacts of pollution from trucks.

EDF was represented at the hearing by Martha Roberts, Erin Murphy, Surbhi Sarang, and John Bullock. Their full testimonies are available here:

EPA is still accepting public comments on the proposed rollback of safeguards against glider truck pollution. You can send your comments through January 5th.

Posted in News| 1 Response

The accelerating market for zero emission trucks

Tesla Semi prototype. Photo: Smnt, Creative Commons

The recent reveal of the Tesla semi-truck is  garnering  attention for the role zero emission vehicles can play in the future of trucking.

Much of the excitement around zero emission trucks stems from the fact that medium-and-heavy duty trucks – critical tools of our modern economy that operate daily in our neighborhoods and communities — have outsized environmental and health impacts.

Trucks today emit dangerous pollutants, including:

Zero emission vehicles are exciting because of their ability to drive progress on all of these pollutants simultaneously.

A clear indicator of the emergence of zero emission trucks is the plethora of recent product announcements from major manufacturers:

Multiple large manufacturers are investing in electric trucks because they recognize a robust, long-term market for these products. These investments reinforce each other by building resilient supply chains, industry knowledge, and production scale.

Most zero emission truck announcements have been for urban or regional vehicle platforms. Urban areas stand to benefit greatly from the significant reduction in local air pollution offered by zero emission trucks because cities’ density means that many people will get to breathe cleaner air. Buses and delivery vehicles typically have modest daily range demands and predicable charging patterns.

Drayage vehicles should be another high-priority for electrification. These trucks run cargo in and out of marine ports and railyards, frequently traversing dense urban neighborhoods. Often these vehicles are among the oldest and highest polluting trucks on the road. Replacing them with zero emission solutions provides critical local air quality benefits to overburdened communities while also driving meaningful greenhouse gas reductions. In fact, the U.S. Environmental Protection Agency estimates that up to 1,200 pounds of nitrogen oxides  and more than 100 pounds  of particulate matter could be reduced annually by replacing an old diesel drayage truck with a zero emission vehicle. More than 12 tons of carbon dioxide would also be reduced each year.

Zero emission solutions are needed for freight operations too. A recent ICCT analysis found wide-scale adoption of electric tractor-trailers in Europe would reduce climate emissions by 115 million tons in 2050 beyond a scenario that relied solely on maximizing diesel truck efficiency. The analysis illustrates a crucial point – in order to get the largest clean air and climate benefits from freight trucks, we will need both zero emission trucks and significantly more fuel efficient diesel trucks. Each vehicle configuration has an important role to play.

The U.S. Clean Trucks program, extended and strengthened in 2016 by the Obama Administration, is a model that other countries can follow for driving efficiency improvements. It sets long-term, protective standards. The latest round of the standards will cut more than a billion tons of carbon emissions and save truck owners $170 billion dollars. The program enjoys broad support among manufacturers, fleets, shippers and clean air advocates.

The Trump Administration has taken aim at key Clean Truck program provisions that drive improvements in trailer design and close a loophole for super-polluting trucks. Defending the popular and effective program from these pernicious attacks must be an imperative for the freight industry. No company wants its freight hauled by a truck that spews 40 times more pollution or contributes to an additional 1,600 premature deaths annually. Electric semi-trucks will of course be pulling trailers. These trailers will need to be designed with fuel efficiency in mind if electric semi-trucks are to deliver on their full potential.

Zero emission freight trucks need to be operated in a manner that minimizes lifecycle emissions across the entire freight system. Thus, green freight best practices are relevant for zero emission vehicles too. These vehicles will need to complement use of freight rail, which emits more than 80 percent less carbon per ton mile than conventional trucks. They will need to be regularly run with full loads to minimize lifecycle emissions per ton mile. They should be charged primarily by renewable energy. All of these actions, made by fleets, will be influenced by the demands of cargo owners.

It is time for companies and communities to pay attention to these zero emission solutions. These trucks have a clear near-term role in urban delivery. Embracing low and zero emissions drayage solutions will provide immediate and significant human health benefits for communities near ports and railyards. In the years ahead, ZEVs will even have a role in longer-haul operations.

Posted in Cars and Pollution, Health, News| Comments are closed

EPA's Pruitt Tries to Open a Loophole to Allow Super-Polluting Trucks on Our Roads

Have you ever seen a truck belching black soot as you drive on the highway and wondered, “isn’t that level of pollution illegal?”

We see less and less of that these days, thanks to common sense standards from the Environmental Protection Agency (EPA) that protect us from this harmful, excessive pollution.

But that progress is now at risk. The current EPA Administrator, Scott Pruitt, is trying to reopen a loophole that would allow the sale of super-polluting trucks that lack modern pollution controls.

The trucks in question are called “glider trucks.” They look new – but their engines are old and polluting. Anyone who likes to breathe air should be concerned.

Loophole would risk as many as thousands of lives a year

Pruitt’s proposed loophole would allow the sale of glider trucks – new trucks with old engines installed in them – without any modern pollution controls.

These super-polluting trucks emit harmful soot and smog-causing pollutants – including oxides of nitrogen, particulate matter, and cancer-causing diesel particulate – at a rate as much as forty times that of new engines. By 2025, glider trucks would comprise just five percent of the nation’s truck fleet, but they would cause one third of the air pollution.

Data that Pruitt’s own agency has collected shows that reopening the loophole could result in as many as 6,400 premature deaths by 2021 from oxides of nitrogen and particulate matter pollution. That assessment is actually conservative, as it doesn’t account for the health harms from cancer-causing diesel particulate pollution or from smog formation caused by these super-polluting trucks.

Benefiting the worst polluters at the expense of responsible companies

Pruitt’s action to reopen this loophole goes against the stated wishes of other truck manufacturers and dealers, who responsibly invested in pollution control equipment and depend on a level playing field for the well-being of their businesses and the Americans they employ.

For example, truck dealership Nuss Trucks commented that:

The original intent of selling gilder [trucks] has moved from a rebuilding mechanism to now mainly evading diesel emissions EPA mandates.

Volvo, the manufacturer of MAC Trucks, noted that the availability of “glider trucks” is creating:

an unlevel playing field for manufacturers of new vehicles designed and certified to be compliant to all current emissions, fuel efficiency, and safety regulations.

So why is Pruitt giving the glider industry special treatment over responsible trucking companies — and over the health of American families?

As recently reported by the Washington Post, Pruitt granted a glider industry request to reconsider the standards after a meeting with a major glider manufacturer in May.

That same manufacturer prominently hosted an event for Donald Trump early in his presidential campaign.

Super-polluting trucks are designed to evade pollution controls

Historically, only a few hundred glider trucks were sold each year. They were typically produced by truck repair shops when a customer wanted to salvage the undamaged engine from a wrecked truck by installing it into a new frame.

But after pollution limits on heavy-duty freight engines were updated in 2010, a small handful of companies recognized a loophole – an opportunity to sell old, dirty engines in new frames, and thereby evade modern pollution standards. The result was mass production of super-polluting trucks that do not come close to meeting current emission standards.

Glider truck manufacturers created a market that didn’t exist before 2010. They made a business out of sourcing large numbers of old, high-polluting engines to sell in new trucks, with sales likely surpassing 10,000 a year in the last few years. The pre-2002 engines they mainly use have essentially no air pollution controls, and cause the classic puff of black diesel smoke you hated to be stuck behind in traffic. (And with good reason, as diesel particulate is known to cause lung cancer.)

EPA took action in 2016 to close the loophole and bring glider truck sales back to pre-2010 levels.

The agency took pains to cause as little disruption as possible while still meeting its responsibility under the Clean Air Act to protect public health and welfare. It phased in the glider truck standards over a period of several years, and never outright banned the sale of glider vehicles (since it recognized the benefit to truckers in being able to salvage the engine from a damaged truck).

Under EPA’s common sense actions to close the loophole, beginning in 2018, glider manufacturers must cap production of high-polluting vehicles at 300 annually beginning in 2018. They may continue to produce additional glider vehicles as long as those meet the modern air pollution controls that all other manufacturers already have to meet.

A decision with devastating consequences for our health  

Pruitt announced his intent to revisit the just-closed loophole in August of this year. He has now released a new proposal to repeal emission requirements for these super-polluting trucks, indicating that he is moving forward with his regressive plan to reopen this loophole and put thousands of lives at risk.

Pruitt’s attempt to repeal these important safeguards reeks of political cronyism, and is being done at the expense of public health. Families and communities across America will be exposed to the dangerous pollution from thousands more of these dirty trucks on our highways. We all deserve better – especially from EPA, the agency with the core mission of protecting us from pollution.

Posted in Cars and Pollution, Clean Air Act, Health, News, Policy| Comments are closed

Why Honeycutt is such an alarming choice for EPA's science advisory panel

Michael Honeycutt – the man set to lead the U.S. Environmental Protection Agency’s prestigious Science Advisory Board – has spent most of his career as a credentialed counterpoint against almost anything the EPA has proposed to protect human health.

Fortunately, his lone voice for the Texas Commission on Environmental Quality rarely carried beyond the Lone Star State. Until now.

The EPA science advisory panel Honeycutt will chair is supposed to provide the agency with independent scientific expertise on a wide range of issues. In a highly unusual move, EPA Administrator Scott Pruitt picked the Texan for the job even though he has never been a member of the board.

More than Honeycutt’s inexperience, however, what worries me most is his faulty logic and what this means for science at the EPA.

Honeycutt downplays ozone dangers

A toxicologist by training, Honeycutt has criticized the EPA’s health-based standards for ozone because “most people spend more than 90 percent of their time indoors,” reducing their exposure to the ubiquitous pollutant.

Houston residents know differently. The city’s worst day for lung-damaging ozone this year happened while many people were outside for long hours of cleanup after Hurricane Harvey.

Honeycutt doubled-down on his position that ozone is not harmful to human health in a 2014 interview with the Texas Tribune.

“I haven’t seen the data that says lowering ozone will produce a health benefit,” he said. “In fact, I’ve seen data that shows it might have a negative health benefit.”

Honeycutt’s statement suggests he believes that more air pollution might actually be good for you.

…even though ozone can cause premature death

I am a toxicologist in Texas, too, and here is the truth about ozone: The pollutant can exacerbate asthma, lung disease and heart disease – and even lead to premature death.

The current acceptable limit, recommended during the George W. Bush administration and set under Obama’s in 2015, is 70 parts per billion, a standard that the public health community still believes is too high. The EPA’s own science advisors had recommended a limit as stringent as 60 ppb to protect human health.

Honeycutt spent millions to refute science

In his Texas role, Honeycutt responded to the recommendation by paying more than $2.6 million for research that says tighter ozone rules would cost the state billions of dollars annually with little or no impact on public health.

“Every part per billion that they don’t lower it is millions of dollars,” Honeycutt told the Houston Chronicle. “So we think that the return on investment in this is just phenomenal. Just phenomenal.”

And it’s not just ozone that seems to be a target for Honeycutt. He also has issues with protections against mercury, particulate matter and air toxics.

The reality is, however, that by failing to improve air quality, we’re paying more in health and social costs. This is real money lost on hospital visits, and on missed work and school days.

…and now he’ll steer EPA science

All this matters because Honeycutt, as the board’s chair, will help prioritize which issues the EPA decides to investigate and pick the scientists who review studies and reports before they come to the full board.

My worry is that he will continue down a path that is destructive to public health protections, a well-known pattern within the Trump administration.

We know that clean air and a strong economy go hand in hand – and that claims by industry doomsayers claims are unsubstantiated.

But none of that matters to an administration that scrubs qualified scientists from serving on advisory committees, that eradicates scientific data from websites that do not support the its agenda, and that does not want to be challenged.

Honeycutt’s appointment is yet another attack against science. With American health at stake, we can not stay silent about this latest EPA development.

This post originally appeared on our EDF Voices blog.

Image source: Source: Flickr/Science Democrats.

Posted in Health, Policy, Science| Comments are closed

It’s now, it’s us, it’s not over – the top 7 takeaways from the new climate change report

Earth as seen from a NOAA weather satellite. Photo: NASA

The U.S. government recently released the Climate Science Special Report (CSSR) – the work of fifty climate science experts who compiled and analyzed the latest knowledge about the physical science of climate change from more than 1,500 scientific journal articles and reports.

The CSSR is often referred to as the first volume of the Fourth National Climate Assessment. National Climate Assessments have been Congressionally mandated since 1990 to be prepared every four years. The second and final volume of the Fourth National Climate Assessment will focus on societal impacts and will be released in 2018.

The CSSR is packed with valuable and scientifically robust information – but it’s almost 600 pages long. If you don’t have time to read it all, don’t worry. We quote some of the most important, and most alarming, facts below.

Here are some of the major takeaways of the CSSR:

It’s now

  • Global average temperature since 1900 is the warmest in the history of modern civilization. Global annually averaged surface air temperature has increased by about 1.8 degrees Fahrenheit (1.0 degrees Celsius) over the last 115 years (1901 to 2016).
  • Sea level rise is accelerating and has already impacted dozens of U.S. cities. Globally averaged sea level has risen by about 7 to 8 inches since 1900, with almost half (about 3 inches) of that rise occurring since 1993. The incidence of daily tidal flooding is accelerating in more than 25 Atlantic and Gulf Coast cities.
  • Several extreme weather and climate events are increasing in intensity and frequency across the U.S. and the world. Heavy rainfall is increasing in intensity and frequency, heatwaves have become more frequent in the United States since the 1960s, and the incidence of large forest fires in the western United States and Alaska has increased since the early 1980s. However, extreme cold temperatures and cold waves are less frequent.
  • Earlier spring melt and reduced snowpack are affecting water resources in the western U.S.

It’s us

  • There is no convincing alternative explanation supported by observational evidence that warming over the last century is caused by anything other than human activities. It is extremely likely that human activities, especially emissions of greenhouse gases, are the dominant cause of the observed warming since the mid-20th century.

It’s not over

  • Without major reductions in emissions, annual average global temperature relative to preindustrial times could increase by 9 degrees Fahrenheit (5 degrees Celsius) or more by the end of this century. With significant reductions in emissions, the increase in annual average global temperature could be limited to 3.6 degrees Fahrenheit (2 degrees Celsius) or less.
  • With further warming comes further sea level rise. Global average sea levels are expected to continue to rise — by at least several inches in the next 15 years and by one to four feet by 2100. A rise of as much as eight feet by 2100 cannot be ruled out. Sea level rise will be higher than the global average on the East and Gulf Coasts of the United States.

The CSSR should put any doubts about whether climate change is a serious threat to rest. The report makes it crystal clear that it is – and that we need to act before it gets worse.

Posted in Basic Science of Global Warming, Extreme Weather, Science| Comments are closed

Everything you need to know about climate tipping points

(This post was co-authored by EDF Climate Scientist Ilissa Ocko)

Imagine cutting down a tree. Initially, you chop and chop … but not much seems to change. Then suddenly, one stroke of the hatchet frees the trunk from its base and the once distant leaves come crashing down.

It’s an apt metaphor for one of the most alarming aspects of climate change – the existence of “tipping elements.”

These elements are components of the climate that may pass a critical threshold, or “tipping point,” after which a tiny change can completely alter the state of the system. Moving past tipping points may incite catastrophes ranging from widespread drought to overwhelming sea level rise.

Which elements’ critical thresholds should we worry about passing thanks to human-induced climate change?

You can see the answer on this graphic – and find more information below.

The most immediate and most worrisome threats

  • Disappearance of Arctic Summer Sea Ice – As the Arctic warms, sea ice melts and exposes dark ocean waters that reflect sunlight much less efficiently. This decreased reflectivity causes a reinforcement of Arctic warming, meaning that the transition to a sea-ice free state can occur on the rapid scale of a few decades. Some scientists have suggested that we have already passed this tipping point, predicting that Arctic summers will be ice-free before mid-century.
  • Melting of the Greenland Ice SheetThe Arctic warming feedback described above may one day render Greenland ice-free. Research predicts that the tipping point for complete melt can occur at a global temperature rise of less than two degrees Celsius – a threshold that may be surpassed by the end of this century. While the full transition to an ice-free Greenland will take at least a few hundred years, its impacts include global sea level rise of up to 20 feet.
  • Disintegration of the West Antarctic Ice Sheet – The bottom of this ice sheet lies beneath sea level, allowing warming ocean waters to slowly eat away at the ice. There is evidence that this tipping point has already been surpassed – possibly as early as 2014. Like the Greenland Ice Sheet, full collapse would require multiple centuries, but it could result in sea level rise of up to 16 feet.
  • Collapse of Coral ReefsHealthy corals maintain a symbiotic relationship with the algae that provide their primary food source. As oceans warm and become more acidic, these algae are expelled from the corals in an often fatal process called coral bleaching. Research predicts that most of our remaining coral systems will collapse even before a global temperature rise of two degrees Celsius.

Tipping points in the distant future

  • Disruption of Ocean Circulation Patterns – The Thermohaline Circulation is driven by heavy saltwater sinking in the North Atlantic, but this water is becoming fresher and lighter as glaciers melt in a warming climate. The change in water density may prevent sinking and result in a permanent shutdown of the circulation. Research suggests that weakening of the Thermohaline Circulation is already in progress, but that an abrupt shutdown is unlikely to occur in this century. Some models suggest that these changes may prompt a secondary tipping element in which the subpolar gyre currently located in the Labrador Sea shuts off. Such a change would dramatically increase sea level, especially on the eastern coast of the United States.
  • Release of Marine Methane HydratesLarge reservoirs of methane located on the ocean floor are stable thanks to their current high pressure-low temperature environment. Warming ocean temperatures threaten the stability of these greenhouse gas reservoirs, but the necessary heat transfer would require at least a thousand years to reach sufficient depth, and may be further delayed by developing sea level rise.
  • Ocean AnoxiaIf enough phosphorous is released into the oceans – from sources including fertilizers and warming-induced weathering, or the breakdown of rocks –regions of the ocean could become depleted in oxygen. However, this process could require thousands of years to develop.

Potentially disastrous elements, but with considerable uncertainty

  • Dieback of the Amazon Rainforest Deforestation, lengthening of the dry season, and increased summer temperatures each place stress on rainfall in the Amazon. Should predictions that at least half of the Amazon Rainforest convert to savannah and grasslands materialize, a considerable loss in biodiversity could result. However, the dieback of the Amazon Rainforest ultimately depends on regional land-use management, and on how El Niño will influence future precipitation patterns.
  • Dieback of Boreal Forests – Increased water and heat stress could also lead to a decrease in boreal forest cover by up to half of its current size. Dieback of boreal forests would involve a gradual conversion to open woodlands or grasslands, but complex interactions between tree physiology, permafrost melt, and forest fires renders the likelihood of dieback uncertain.
  • Weakening of the Marine Carbon Pump – One mechanism through which oceanic carbon sequestration takes place is the marine carbon pump, which describes organisms’ consumption of carbon dioxide through biological processes such as photosynthesis or shell building. As ocean temperatures rise, acidification progresses, and oxygen continues to be depleted, these natural systems could be threatened and render the carbon sequestration process less efficient. More research is necessary in order to quantify the timescale and magnitude of these effects.

Tipping elements complicated by competing factors

  • Greening of the Sahara/Sahel As sea surface temperatures rise in the Northern Hemisphere, rainfall is projected to increase over the Sahara and Sahel. This increased rainfall would serve to expand grassland cover in the region, but is balanced by the cooling effect of human-emitted aerosols in the atmosphere.
  • Chaotic Indian Summer MonsoonThe fate of the Indian Summer Monsoon similarly depends upon a balance of greenhouse gas warming and aerosol cooling, which strengthen and weaken the monsoon, respectively. On the timescale of a year, there is potential for the monsoon to adopt dramatic active and weak phases, the latter resulting in extensive drought.

More research necessary to establish as tipping elements

  • Collapse of Deep Antarctic Ocean CirculationAs in the case of the Thermohaline Circulation, freshening of surface waters in the Southern Ocean due to ice melt may slowly alter deep water convection patterns. However, the gradual warming of the deep ocean encourages this convection to continue.
  • Appearance of Arctic Ozone HoleUnique clouds that form only in extremely cold conditions currently hover over Antarctica, serving as a surface for certain chemical reactions and facilitating the existence of the ozone hole. As climate change continues to cool the stratosphere, these “ice clouds” could begin formation in the Arctic and allow the development of an Arctic ozone hole within a year.
  • Aridification of Southwest North America As global temperatures rise, consequential changes in humidity prompt the expansion of subtropical dry zones and reductions in regional runoff. Models predict that Southwest North America will be particularly affected, as moisture shifts away from the southwest and into the upper Great Plains.
  • Slowdown of the Jet Stream A narrow and fast moving air current called a jet stream flows across the mid-latitudes of the northern hemisphere. This current separates cold Arctic air from the warmer air of the south and consequentially influences weather in its formation of high and low pressure systems. A slowing of the jet stream has been observed over recent years. Should slowing intensify, weather patterns could persist over several weeks with the potential to develop into extended extreme weather conditions.
  • Melting of the Himalayan Glaciers – Several warming feedbacks render the Himalayan glaciers vulnerable to dramatic melt within this century, though limitations on data availability complicate further study. Dust accumulation on the mountainous glaciers and the continual melt of snow and ice within the region both prompt a decrease in sunlight reflectivity and amplify regional warming.

Gradual, continuous changes

  • More Permanent El Nino State90 percent of the extra heat trapped on Earth’s surface by greenhouse gases is absorbed by the oceans. Though still under debate, the most likely consequence of this oceanic heat uptake is a gradual transition to more intense and permanent El Nino/Southern Oscillation (ENSO) conditions, with implications including extensive drought throughout Southeast Asia and beyond.
  • Permafrost MeltingAs global temperatures rise and the high latitudes experience amplified warming, melting permafrost gradually releases carbon dioxide and methane into the atmosphere and creates a feedback for even more warming.
  • Tundra Transition to Boreal Forest – Much like the conversion of the Amazon Rainforest and boreal forests to other biomes, tundra environments may transition into forests as temperatures increase. However, this process is more long-term and continuous.

With a range of critical thresholds on the horizon, each tipping element demonstrates the potential implications of allowing climate change to progress unchecked.

As tipping points loom ever closer, the urgency for emissions mitigation escalates in hopes of sustaining the Earth as we know it.

Posted in Arctic & Antarctic, Basic Science of Global Warming, Extreme Weather, Oceans, Science| Comments are closed
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