Climate 411

Cherry blossoms: a microcosm of the global climate crisis

Cherry blossoms in Washington, D.C. reached peak bloom extremely early this year. Photo by Ilissa Ocko

(This blog was co-authored by EDF Climate Scientist Fiona Lo)

Washington D.C.’s famous cherry blossoms are once again blooming earlier than expected.  

In fact, this year’s peak bloom occurred two and a half weeks earlier than the average over the past 100 years, due to near-record warm temperatures in March. 

This ranks as the second earliest peak bloom on record. Even the cherry blossom bud cycle occurred faster than any other year in the last two decades.  

So what is happening and why is this significant?  

Here we break down what you need to know about cherry blossoms and climate change. 

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Posted in Agriculture, Basic Science of Global Warming, Extreme Weather, News, Science / Comments are closed

A U.S. economy-wide methane target: essential, achievable, affordable

The Biden administration is preparing to announce a new U.S. greenhouse gas emissions target for 2030 under the Paris Agreement — a pledge known as a Nationally Determined Contribution, or NDC — in advance of this year’s United Nations climate talks. Given the last four years of U.S. climate inaction and denial, it is important that the U.S. put forward an ambitious yet credible target and restore its position as a global leader on climate.

Although many countries pledge a single headline target that includes all greenhouse gas emissions, we believe that a complementary methane target is an essential addition that will considerably benefit the climate. Although it would include methane, a combined target is not sufficient to ensure that immediate and strong actions are taken to reduce methane emissions at the extent warranted.

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Posted in Greenhouse Gas Emissions, Paris Agreement, Science / Read 2 Responses

What you need to know about hurricanes and climate change

Photo: NOAA

This post was co-authored by EDF Postdoctoral Climate Science Fellow Tianyi Sun

Today Hurricane Laura made landfall in Louisiana as a Category 4 hurricane, causing death and destruction. Louisianans and Texans in its path are now mourning and looking ahead to a long and painful recovery.

Laura had winds up to 150 miles per hour, making it one of the strongest hurricanes on record to ever hit the Gulf Coast in the United States. It tied the record for how quickly it intensified, driving questions about the role of climate change in creating and fueling this monster storm.

A look at the latest science

Scientists have been actively studying how climate change affects hurricanes for decades, and the evidence that it can influence several aspects of hurricanes continues to grow.

Overall, climate change is making these already dangerous weather events even more perilous. They are stronger, wetter, slower, and intensify more rapidly. Major storms are occurring more often and piling on heavier rainfall, and scientists anticipate the strongest storms will continue to increase in frequency. Sea level rise, along with stronger winds, are also worsening storm surges, causing more coastal flooding.

All aspects of hurricanes – from formation to track to strength to damages – can be influenced to some degree by climate change, through warmer waters, more moisture in the atmosphere, changing air patterns, and sea level rise.

For some connections, such as how climate change affects hurricane strength and its damages, the science is simple and robust. For other connections, such as how climate change affects hurricane formation and track, the science is more complicated and nuanced.

Here we break down what we know about how climate change affects four key aspects of hurricanes


1. Hurricane formation – competing factors at play
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Posted in Basic Science of Global Warming, Extreme Weather, News, Oceans, Science / Comments are closed

Hansen was right: Marking an anniversary by misleading the public

Dr. James Hansen testifying before Congress in 1988

With the thirtieth anniversary of former NASA scientist Jim Hansen’s landmark testimony to Congress on the urgent need to address climate change, numerous articles marked the occasion by demonstrating that his 1988 predictions have proven to be accurate.

Inevitably, some writers seized the opportunity to revive long-debunked arguments in an attempt to cast doubt and confusion on the threat.

Perhaps the most misleading – and certainly the highest profile – was a June 21st op-ed in the Wall Street Journal written by Pat Michaels and Ryan Maue. Michaels is director of the Center for the Study of Science at the Cato Institute, a think tank financially linked to the fossil fuel industry. And Michaels has been found to have previously misled Congress by presenting a doctored graph of Hansen’s projections during public testimony before the House Small Business Committee.

Four decades of climate model projections have fared well

Their latest effort implies that U.S. climate policy is based on Hansen’s forecasts in 1988, and therefore we must “reconsider environmental policy” according to an evaluation of “how well his forecasts have done.”

In reality, climate policy is based on hundreds of years of collective research and an overwhelming amount of observational evidence gathered from all over the world.

Climate model development began as early as the 1950s, and projections from 1973 to 2013 (including Hansen’s 1988 paper) have been compared to observed temperatures by multiple institutions. All showed reasonably accurate surface temperature increases between 1970 and 2016, Hansen’s 1988 study included.

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Posted in Basic Science of Global Warming, Greenhouse Gas Emissions, News, Science, Setting the Facts Straight / Comments are closed

Natural disasters are no longer purely natural

You may have heard the alarming news that weather and climate disasters in the U.S. killed 362 people in 2017 and caused a record $306 billion in damages.

But also alarming is the fact that many news outlets are still referring to these events as “natural disasters.”

Southeast Texas after Hurricane Harvey – a not-purely-natural disaster. Photo: U.S. Department of Defense

With recent advances in science, researchers have found that human-caused climate change plays a major role in making certain events occur and/or making them worse. That means that many “natural disasters” are no longer purely “natural.”

Here is a look at some not-so-natural disasters:

  • Hurricane Harvey 2017: human-caused climate change made record rainfall over Houston around three times more likely and 15 percent more intense
  • European Extreme Heat 2017: human-caused climate change made intensity and frequency of such extreme heat at least 10 times as likely in Portugal and Spain
  • Australian Extreme Heat 2017: maximum summer temperatures like those seen during 2016-2017 are now at least 10 times more likely with human-caused climate change
  • Louisiana Downpours 2016: human-caused climate change made events like this 40 percent more likely and increased rainfall intensity by around 10 percent
  • European Rainstorms 2016: human-caused climate change made probability of three-day extreme rainfall this season at least 40 percent more likely in France
  • UK Storm Desmond 2015: human-caused climate change made extreme regional rainfall roughly 60 percent more likely
  • Argentinian Heat Wave 2013/2014: human-caused climate change made the event around five times more likely

By employing the term “natural disasters,” news outlets and others are inadvertently implying that all of these events are just misfortunate incidences – rather than consequences of our actions.

This seemingly innocuous phrase supports the idea that dangerous weather is out of our control.

But, we do have some control over their frequency and intensity, and that control is through our emissions of heat-trapping gases.

We need to act on climate, and we need to do it now. Pointing out that we worsen and may even cause these weather disasters may help convince people to do what needs to be done.

Posted in Basic Science of Global Warming, Extreme Weather, News, Science, Setting the Facts Straight / Read 1 Response

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