Climate 411

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

By Ilissa Ocko / Published: November 15, 2017

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.

Also posted in Extreme Weather, Science / Comments are closed

Everything you need to know about climate tipping points

By Casey Ivanovich / Published: November 1, 2017

(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 Sheet – The 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 Reefs – Healthy 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 Hydrates – Large 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 Anoxia – If 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 Monsoon – The 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 Circulation – As 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 Hole – Unique 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 State – 90 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 Melting – As 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.

Also posted in Arctic & Antarctic, Extreme Weather, Oceans, Science / Comments are closed

Pruitt takes steps to remove science from decisions affecting the health of American families

By Sarah Vogel / Published: October 31, 2017

Today EPA Administrator Scott Pruitt announced additions to the Agency’s Scientific Advisory Board (SAB) and the Clean Air Scientific Advisory Committee (CASAC). Taken in conjunction with the drastic policy shift also announced today, Pruitt is set to fundamentally undercut the role science in driving EPA decisions that directly affect the health and safety of American families and communities.

The new policy would exclude any scientist receiving an EPA grant from serving on any of the agency’s advisory panels. This creates a profound hypocrisy: under the policy scientists who take money from ExxonMobil or even Russia—since funding from other governments wouldn’t be disqualifying—Pruitt would regard as trusted to offer impartial advice. Meanwhile, those who have grants from the US environmental agency – whose research program was praised by the National Academy of Sciences in a report just this past summer – cannot.

In Pruitt’s Alice-in-Wonderland world, the EPA advisory panels intended to ensure the agency is making use of the best and latest science should be populated overwhelmingly by industry-affiliated scientists, at the expense of independent academic scientists.

Along with the policy, Pruitt’s new appointments to the SAB and CASAC (see a selection of the reported additions below) include longtime fossil fuel and chemical industry advocates, who have consistently played down or outright dismissed concerns about the risks of pollution or toxic chemical exposures based on discredited and outrageous scientific claims. Although the SAB is supposed to “provide independent advice and peer review on the scientific and technical aspects of environmental issues to the EPA’s Administrator,” these additions cannot be relied upon to faithfully uphold the Board’s mission.

Meanwhile, Pruitt is also reportedly taking the unprecedented step of not renewing any appointments for members whose terms expire this year. This allows Pruitt to reshape the panel in his own image more quickly.

All told, the goal is as clear as it is concerning: to create a rubber-stamp set of scientific advisers that can distort the science while still lending an aura of credibility to Pruitt’s destructive actions at the Agency.

The real losers are not the researchers, but rather American families who depend on having an agency that actually works to protect their health.

Meet some of Mr. Pruitt’s new science advisers

Texas official with a long record of downplaying health concerns about pollutants and toxic chemicals ranging from ozone to benzene. Honeycutt argued against stronger ozone standards by noting most people spend their days indoors. He also claimed that “some studies even suggest that PM [particulate matter] makes you live longer.”

Denver-based consultant with long track record of conducting research that disputes the public health benefits of reducing air pollution. Cox has stated that there is “no evidence that reductions in air pollution levels have caused any reductions in mortality rates.”

Record of disputing the benefits of clean air and air pollution limits; said that “Modern air … is a little too clean for optimum health.”

Professor at NC State affiliated with the climate-denying Heartland Institute, who claims that the “evidence is overwhelming” that if temperatures do increase, it will be “better for humans.”

Former Secretary of North Carolina Department of Environmental Quality (NCDEQ), who questions the well-established scientific consensus of climate change and, had a controversial tenure at the agency, notably over health advisories to well owners whose water might have been contaminated by coal ash.

Smith is a Managing Director of NERA Economic Consulting and co-head of its environmental practice. In work funded by the fossil fuel industry trade group the American Petroleum Institute, Smith argued that EPA data on lung response to ozone is imprecise, roundly debunked by policy experts and independent fact-checkers.

Also posted in Health, Science, Setting the Facts Straight / Comments are closed

A real Halloween horror story: the five scariest aspects of climate change

By Casey Ivanovich / Published: October 30, 2017

Halloween has arrived, and it’s time once again for goblins, gremlins, and ghost stories.

But there’s another threat brewing that’s much more frightening – because it’s real.

An unrecognizable world is quickly creeping up on us as climate change progresses – and the anticipated impacts are enough to rattle anyone’s skeleton.

Here are five of the scariest aspects of climate change. Read on if you dare ….

  1. Extreme weather is becoming more extreme

A changing climate paves the way for extreme weather events to live up to their name.

In 2017 alone we saw fatal events worldwide, including:

The fingerprints of climate change can be found on each of these events.

As global temperatures continue to rise, heat waves are expected to become more intense, frequent, and longer lasting.

Scientists also predict that rainfall patterns will continue to shift, increasing regional risk for widespread drought and flooding.

Montana, 2002. Photo: U.S. Forest Service

Drought conditions may also prompt wildfires to occur more frequently and within a longer fire season. The wildfire season in the western U.S. is already weeks longer than in previous years.

Hurricanes are also influenced by climate change. Rising sea surface temperatures, a moister atmosphere, and changing atmospheric circulation patterns have the potential to increase hurricanes’ power and travel paths.

Extreme weather intensification impacts human health and development in many ways – extreme heat events directly generate health hazards such as heat stroke, while drought and wildfires threaten crop and ecosystem stability.

The 2017 hurricane season has already demonstrated the shocking consequences of intensified hurricanes and flooding, with Hurricanes Harvey, Irma, and Maria killing more than 150 people and causing as much as $300 billion in damages in the U.S. alone.

  1. Tipping points loom in near future

A particularly alarming facet of climate change is the threat of irreversible changes to climate conditions, called “tipping elements.”

These components of the climate system earn their title from a possession of critical thresholds, or “tipping points,” beyond which a tiny change can dramatically alter the state of the system.

Many tipping elements have been identified by scientists, and some may have already passed their critical threshold. For example, a vicious cycle of sea ice melt has already been triggered, leading scientists to predict that Arctic summers will be ice-free before mid-century.

Imminent tipping points also exist for melting ice sheets, particularly those of Greenland and West Antarctica, where full ice sheet collapse could result in global sea level rise of up to 20 feet and 16 feet respectively.

Coral reefs too are rapidly approaching a grave tipping point. Essential relationships between algae and corals begin to break down as ocean waters rise in temperature and acidity. Without stabilizing these changes, the majority of global reef systems may collapse before global temperatures reach a two-degree Celsuis warming threshold.

  1. Coastal communities battle sea level rise

Sea level rise is one of the most visible impacts of climate change, as increased coastal erosion physically erases continental borders.

As the climate warms, ocean waters expand and ice sheets and glaciers melt. Both factors contribute to a rising sea level at an accelerating rate. Communities in Alaska and several Pacific Islands are already fleeing rising seas – relocating as their villages are engulfed and eroded.

Rising sea levels also intensify damages from extreme weather events such as hurricanes. A higher sea level allows storm surges to grow in height and volume, exacerbating flooding and associated damages.

As water levels continue to rise, more coastal communities will feel the consequences. Many major cities are located on coastlines, with almost 40 percent of U.S. citizens living in coastal cities.

Protecting people from this creeping threat will be difficult and costly – as we’ve already seen in the aftermath of coastal storms such as Superstorm Sandy.

  1. Humans are nearing uncharted climate territory

A globally averaged two-degree Celsius (or 3.6 degrees Fahrenheit) of warming over preindustrial levels is the most widely suggested threshold we need to stay “well” below.

The threshold was first proposed by William Nordhaus in the 1970’s, in part because of its historical significance – the human species has never lived during a time in which global temperatures were equivalent to two-degrees Celsius above preindustrial levels.

The unprecedented nature of this benchmark provided a foundation for alarm that carried the two-degrees Celsius value into political and scientific discussions for decades.

In a changing climate, unprecedented events will become the norm.

In some cases, they already have.

As infectious diseases spread to previously untouched regions and an Arctic ozone hole threatens to open, people are beginning to catch the first glimpses of the new world we are creating – one that is in many ways more hostile and dangerous than the one we leave behind.

  1. Many American politicians deny the problem

Perhaps the only thing more terrifying than the impacts of climate change is the overwhelming denial of their existence by some political leaders in the U.S.

The Paris Agreement served as a major step forward in promoting climate change mitigation policy on an international scale, with almost every nation agreeing to tackle this looming threat.

Then in June, President Trump announced his intent to withdraw from the agreement. That means the United States will be one of only two countries – out of almost 200 – failing to participate in the accords.

The same efforts towards dismantling U.S. climate progress can be seen in recent national policy. Environmental Protection Agency Administrator Scott Pruitt (who recently claimed that carbon dioxide is not a major contributor to global warming) is perhaps the most visible of an exhausting list of leaders within the current Administration who deny climate science. The Administration is trying to undermine or reverse policies addressing climate change, including the Clean Power Plan, and information about climate change is vanishing from official agency websites.

The rest of the globe is striving to implement meaningful climate policy, including China’s unparalleled growth in renewable energy support. Soon the U.S. will be left in the dust in the race for a greener world.

Be afraid. Be very afraid. Then do something about it.

We can’t protect you from the monsters hiding under your bed. But combating the ominous impacts of climate change is a much more hopeful endeavor.

For more information on how you can help, click here.

 

Also posted in Arctic & Antarctic, Extreme Weather, International, News, Oceans, Policy, Science / Read 2 Responses

The Clean Power Plan’s enormous climate benefits – in one graphic

By Ilissa Ocko / Published: October 10, 2017

In addition to the vital public health benefits it offers, the Clean Power Plan is the nation’s most significant action to date to address climate change’s number one culprit – heat-trapping carbon dioxide emissions.

Now, EPA Administrator Scott Pruitt is trying to revoke the Clean Power Plan. Here’s a look at the enormous benefits we could lose.

When the Clean Power Plan is fully in place by 2030, the avoided annual carbon dioxide emissions relative to business-as-usual (350 million metric tons) are equivalent to preventing:

  • 40 billion gallons of gasoline consumed, or
  • 380 billion pounds of coal burned, or
  • 810 million barrels of oil consumed, or
  • 850 billion miles driven by an average car.

In order to get the same climate benefits that the Clean Power Plan would deliver, we would need to:

  • Replace 12 billion incandescent light bulbs with LEDs, or
  • Take 75 million cars off the road

Click to enlarge

 

Also posted in Clean Power Plan, Greenhouse Gas Emissions, News, Science / Read 1 Response

Five takeaways from Scott Pruitt’s reported proposal to revoke the Clean Power Plan

By Martha Roberts / Published: October 6, 2017

Today, a draft proposal emerged of the latest step in Environmental Protection Agency (EPA) Administrator Scott Pruitt’s attack on clean air and climate security – a proposal to revoke the Clean Power Plan, America’s only nationwide limit on carbon pollution from power plants.

The proposal offers no commitment to do anything to address dangerous carbon pollution from existing power plants – our nation’s largest industrial source of this harmful pollution.

Here are five key takeaways from the proposal that emerged today.

1. Devaluing the health and well-being of all Americans

The Clean Power Plan would deliver tremendous benefits to American communities by reducing harmful pollution. For example, EPA estimates the Clean Power Plan will prevent up to 3,600 premature deaths and 90,000 childhood asthma attacks every year once it is fully implemented.

But in a vivid example of how little Administrator Pruitt prioritizes public health, this proposal uses discredited methods to justify the view that premature deaths and other significant health impacts from harmful air pollution don’t exist and don’t matter. It even undercuts the harms we face from carbon pollution by using methods at odds with leading experts, including the National Academy of Sciences.

Administrator Pruitt is trying to paint over the fact that undoing the Clean Power Plan will expose Americans to dirtier air, and will delay urgently needed action to address climate change.

Asthma attacks, heart attacks, floods and storm surges, wildfires, droughts, and heat waves hurt real people. EPA has a responsibility to protect the public — but Pruitt has made a priority of protecting the fossil fuel interests that have propelled his political career.

2. Repeal-without-replace

Across America, the past weeks of extreme weather have provided a tragic reminder of the threats we face from climate change. Hurricanes exacerbated by climate change – like Maria, Harvey, and Irma – have left millions reeling, with lives lost and communities profoundly disrupted for years to come.

Yet the draft proposal makes no commitment to protect Americans from dangerous climate change. Instead it “continues to consider” whether to protect Americans from carbon pollution from existing power plants (ignoring settled law that EPA must issue safeguards against climate pollution under the Clean Air Act – as the Supreme Court has already concluded three times.)

Administrator Pruitt chastised others for asking about climate change after Hurricanes Harvey and Irma hit, saying the timing was “insensitive.” But at that same time, he was working to roll back our nation’s most significant effort to protect Americans from climate change.

3. America should be moving ahead on clean power – not going backwards

Power market trends are moving towards cleaner power sources, creating jobs and shared economic prosperity across the country.

More and more evidence shows that achieving the Clean Power Plan’s goals will be even cheaper than expected. Yet Administrator Pruitt’s draft uses accounting gimmicks to claim costs would somehow be higher than originally anticipated.

If anything, the Clean Power Plan’s targets should be stronger. But Administrator Pruitt now seems to be pulling out the stops to shield polluting power plants from taking any steps to reduce their harmful impacts.

4. Who benefits? Pruitt’s political allies

Scott Pruitt built his political career by suing relentlessly to block EPA safeguards, including the Clean Power Plan.

Pruitt’s campaigns and political organizations received extensive contributions from Clean Power Plan opponents, including $25,000 from coal company Murray Energy just one month before the Clean Power Plan oral argument.

Those Clean Power Plan opponents now stand to benefit from this draft proposal – at the expense of the health and safety of American families.

5. Americans speak out for the Clean Power Plan

When President Trump issued an executive order in March that threatened to roll back the Clean Power Plan, Americans across the country responded with an outpouring of support.

Groups supporting the Clean Power Plan included: faith organizations; health associations; at least 75 mayors, state governors, and attorneys general representing nearly half the U.S. population; power companies; and leading companies like Apple, General Electric, and Walmart.

A similarly broad and diverse coalition has been defending the Clean Power Plan in court –including eighteen states and sixty municipalities across the country; power companies that own and operate nearly ten percent of the nation’s generating capacity; consumer and ratepayer advocates; and many others.

In a recent nationwide poll, almost 70 percent of Americans expressed support for strict limits on carbon pollution from existing power plants – including a majority of Americans in every Congressional district in the country.

Please join us to fight for the Clean Power Plan. You can take action here.

Also posted in Clean Air Act, Clean Power Plan, Extreme Weather, News, Policy, Science / Comments are closed