Tournament Earth: Round 2 Open for Voting

March 8th, 2016 by Kevin Ward

Tournament Earth 2016 Round 2

How did you fare in the opening round of Tournament Earth 2016? One of my favorite photos, showing Mauna Kea volcano has already gone down in defeat. The top seeds moved on to the next round with the exception of Laguna Colorado that fell to an upstart view of New Zealand in sunglint. What will happen in Round 2? Anything is possible. Polls are open for you to vote for the sixteen images that remain through Friday at 4:00 p.m. EDT / 8:00 p.m. UTC. Vote at http://earthobservatory.nasa.gov/TournamentEarth/

Himalayan Heights

March 4th, 2016 by Adam Voiland

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On March 1, 2016, NASA astronaut Scott Kelly returned to Earth after spending 340 days living continuously in space. That’s a record. No other American astronaut has completed a longer mission or spent more cumulative days in space.

A prolific and talented photographer, Kelly posted hundreds and hundreds of photographs of the Earth below to social media during his flight. In a fitting finale for the record-breaking explorer, one of the last photos he posted from orbit was this hazy blue scene of the Himalayas.

“The Himalayas remind me of the bigger view we see when we conquer the mountains we climb,” he said on Twitter. The tip of mountain Mount Everest is about 8.8 kilometers (5.5 miles) above sea level; Kelly was in orbit about 250 kilometers above sea level. Over the course of the mission, he traveled some 231,498,541 kilometers.

Congratulations, Scott, on your safe return. Thank you for the beautiful photos. And keep climbing.  (The image below, an astronaut photograph taken in 2013, shows K2, one the most treacherous mountains in the world for climbers. Read more about the 8K peaks here.)
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Remember to Vote

March 1st, 2016 by Mike Carlowicz

Here in the U.S., it’s election season. Don’t forget to vote.

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A Grim Visit to a Marine Mammal Hospital

February 29th, 2016 by Adam Voiland

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While I was in San Francisco in the fall of 2015, I headed across the Golden Gate Bridge to take a tour of The Marine Mammal Center, a nonprofit veterinary research hospital in Sausalito, California. I had heard that a blob of unusually warm water off the Pacific coast had taken a toll on marine life and caused an increase in the number strandings.

When I visited on December 16, 2015, the hospital was taking care of 81 northern fur seals, 7 California sea lions, 1 northern elephant seal, and 1 Guadalupe fur seal. That is a lot of northern fur seals—three times more than the center rescued the previous year and more than twice the previous record, which was set in 2006.

While sea lions, elephant seals, and Guadalupe fur seals were scarce when I visited, had I come earlier in the year there would have been plenty of these species as well. By February 2015, the center had rescued record numbers of starving sea lion pups; by April, they were dealing with record numbers of elephant and harbor seals; by June, they had taken in five times the normal number of Guadalupe fur seals.

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A northern fur seal resting on a warming mat. Photo by Adam Voiland.

The photograph above shows one of the northern fur seals resting on a warming mat. “Northern fur seals are smaller, furrier and feistier than the California sea lion pups we rescued earlier this year,” noted Shawn Johnson, the director of veterinary science at The Marine Mammal Center, in a November press release. “But otherwise the scene here is the same—our rescue trucks continue to arrive day after day with more starving pups in need of our care.” By the end of the year, the center had rescued 1,800 animals, breaking nearly every record in the facility’s 40-year history.

What was causing all of the trouble? Most marine scientists think the warm water blob in the northeast Pacific was a key culprit. The warm water was driven by the emergence of an unusually strong and persistent ridge of atmospheric high pressure in the northeastern Pacific Ocean. The feature, which was so unrelenting that meteorologists took to calling it the Ridiculously Resilient Ridge, weakened winds in the area enough that the normal wind-driven churning of the sea eased.

Those winds usually promote upwelling, which brings deep, cool water up toward the surface; instead, the resilient ridge shut down the ocean circulation, leaving a large lens of unusually warm surface water in the northeastern Pacific. Upwelling brings dissolved nutrients to the surface, so the slowdown in upwelling meant many animals had less to eat. In addition, the warm water extended the time that  certain type of algae bloom produced toxins that can cause serious health problems for marine mammals.

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The maps below show sea surface temperature anomalies in the Pacific in July 2015. Large patches of warm water dominated the Gulf of Alaska and along the California coast. The map is based on data collected by the U.S. Navy’s WindSAT instrument on the Coriolis satellite and the AMSR2 instrument on Japan’s GCOM-W. Note that the maps do not depict absolute temperatures; instead, they show how much above (red) or below (blue) water temperatures were compared to the average from 2003 to 2012.

The good news it that the blob has finally broken up. By January 2016, more seasonable temperatures had returned to the northeast Pacific, thanks to the strong El Niño in the equatorial Pacific. The breakup of the warm blob came as no surprise to weather watchers. In September 2015, Clifford Mass, a University of Washington atmospheric scientist, explained in his blog that El Niño generally brings lower-than-normal sea surface pressures to the eastern Pacific—the opposite of the systems that sustained the blob. By mid-December 2015, around the time that I was visiting the Marine Mammal Center, Mass declared that the blob was dead.

However, remnants of the warm blob still persist. “There are significant temperature anomalies extending down to a depth of about 300 meters. So while the weather patterns the past few months have not been that favorable to warming, it will take a while for all of the accumulated heat to go away,” explained Nicholas Bond, a University of Washington meteorologist and Washington state’s climatologist. That means impacts on marine life and on weather in the Pacific Northwest could linger, though Bond does not think the blob will return in the near term.

The type of type of algae that has caused harmful blooms is Pseudonitzschia, which produces the neurotoxin domoic acid. The Marine Mammal Center is where scientists first discovered (in 1998) that domoic acid could be toxic to marine mammals. The toxin accumulates in shellfish, sardines, and anchovies, common food sources for marine mammals. Exposure to domoic acid affects the brains of mammals; it can cause them to become lethargic, disoriented, and have seizures that sometimes result in death.

High levels of domoic acid likely contributed to the record number of marine mammal strandings. Since the toxin can also affect humans and was found in the meat of commercial fish and crabs (rather than just the guts), authorities also closed major fisheries including Dungeness and rock crab, anchovy, oyster, razor clams, and mussels in 2015.

In many areas, domoic acid remained a concern in mid-February 2016. Though the situation has improved somewhat, California’s commercial dunegrass crab season will remain closed until more of the coast is clear of the toxin, according to the San Francisco Chronicle.

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Meanwhile, National Oceanic and Atmospheric (NOAA) scientists recently reported that domoic acid is present in Alaskan marine food webs in high enough concentrations to be detected in marine mammals such as whales, walruses, sea lions, seals, porpoises and sea otters. “Since 1998, algal toxin poisoning has been a common occurrence in California sea lions in Central California. However, this report is the first documentation of algal toxins in northern ranging marine mammals from southeast Alaska to the Arctic Ocean,” a NOAA press release said.

“We do not know whether the toxin concentrations found in marine mammals in Alaska were high enough to cause health impacts to those animals. It’s difficult to confirm the cause of death of stranded animals. But we do know that warming trends are likely to expand blooms, making it more likely that marine mammals could be affected in the future,” NOAA research scientist Kathi Lefebvre said.

For more details about the unusual conditions in the Pacific Ocean, see this story from the University of California.

February Puzzler

February 24th, 2016 by Adam Voiland

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Every month on Earth Matters, we offer a puzzling satellite image. The February 2016 puzzler is above. Your challenge is to use the comments section to tell us what part of the world we are looking at, when the image was acquired, what the image shows, and why the scene is interesting.

How to answer. Your answer can be a few words or several paragraphs. (Try to keep it shorter than 200 words). You might simply tell us what part of the world an image shows. Or you can dig deeper and explain what satellite and instrument produced the image, what spectral bands were used to create it, or what is compelling about some obscure speck in the far corner of an image. If you think something is interesting or noteworthy, tell us about it.

The prize. We can’t offer prize money, but, we can promise you credit and glory (well, maybe just credit). Roughly one week after a puzzler image appears on this blog, we will post an annotated and captioned version as our Image of the Day. In the credits, we’ll acknowledge the person who was first to correctly ID the image. We’ll also recognize people who offer the most interesting tidbits of information about the geological, meteorological, or human processes that have played a role in molding the landscape. Please include your preferred name or alias with your comment. If you work for or attend an institution that you want us to recognize, please mention that as well.

Recent winners. If you’ve won the puzzler in the last few months or work in geospatial imaging, please sit on your hands for at least a day to give others a chance to play.

Releasing Comments. Savvy readers have solved some of our puzzlers after only a few minutes or hours. To give more people a chance to play, we may wait between 24-48 hours before posting the answers we receive in the comment thread.

Good luck!

Update: The answer is posted here.

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Oreopoulos explains cloud optical thickness in front of the NASA hyperwall. Photo courtesy of L. Oreopoulos

Earth Matters occasionally publishes interviews with NASA earth scientists from around the agency. Here we feature Lazaros Oreopoulos, chief of the Climate and Radiation Laboratory at Goddard Space Flight Center.

Can you describe your job?
I have three roles. For the last two-and-a-half years, I’ve been the chief of the Climate and Radiation Lab, so that makes me a first-line supervisor. I manage the affairs of the lab of about 70 people that I joined in 1997.

I’m also deputy project scientist of the Aqua mission. Aqua was launched in 2002 as part of the Earth Observing System missions. Aqua measures various atmospheric, land surface, ocean and ice properties.

My third role is as a scientist studying the interaction of clouds with atmospheric radiation. I use satellite observations to understand cloud properties explaining the role of clouds and climate. I’m also trying to improve cloud representation in global climate models.

Clouds are notoriously hard to study. They come in so many different shapes, sizes and internal structures. A major question is how clouds will impact future climate change, whether they will mitigate or enhance the rate of change. We don’t have a long enough record of how clouds may have changed over the years to help us answer this question. It is challenging to reconstruct the record backwards, but satellite observations are the best way to construct records from the recent past forward.

map shows an average of all of the satellite’s cloud observations between July 2002 and April 2015. Colors range from dark blue (no clouds) to light blue (some clouds) to white (frequent clouds). NASA Earth Observatory images by Jesse Allen and Kevin Ward, using data provided by the MODIS Atmosphere Science Team, NASA Goddard Space Flight Center.

This map shows an average of all Aqua MODIS cloud observations between July 2002 and April 2015. Colors range from dark blue (no clouds) to light blue (some clouds) to white (frequent clouds). Read more about the image here. NASA Earth Observatory images by Jesse Allen and Kevin Ward, using data provided by the MODIS Atmosphere Science Team, NASA Goddard Space Flight Center.

What makes your lab unique?

Our lab is an international group of scientists with various backgrounds who are all top experts in their fields. Most of our civil servant scientists were not born in the U.S. Many of them came to Goddard via a complicated, difficult path. Some survived the dissolution of their countries’ governmental systems. Another lived through a civil war during his childhood. As a result, little problems don’t scare or phase them. Their strong character puts everything in perspective because they have been through much worse. It makes them persevere and be persistent. They are also very, very happy to be here with all the means available to do what they love.

Our winter party celebrating the new year has a strong international flavor. We have a potluck party where people bring dishes representing the cuisine of their home countries. The accompanying slideshow with photos from their travels or youth years is quite entertaining.

Our group really doesn’t think about ethnic differences; we understand that we live in an international environment and are always accepting of cultural differences. Our party is one more opportunity to share experiences and backgrounds.

How do you keep such an international group moving in the same direction?

We have a lot of strong personalities, which is an asset. We try to stay focused on the science and our overarching goal, which is to fulfill our mission. We won’t stop until we’ve accomplished our goal.

Montreal at night on December 24, 2010. The image was taken on the International Space Station by Expedition 26 crew. Read more about the image here.

Montreal at night. This photograph was taken from the International Space Station by Expedition 26 crew. Read more about the image here.

Please tell us about your international background.

I have lived in four countries. I speak Greek, English, French and German.

I was born in a small Bavarian town in Germany close to the Austrian border near Salzburg. My parents were poor Greeks who immigrated in the ’60s seeking a better life. We returned to Greece when I started school. I went to Aristotle’s University in Thessaloniki, Greece, eventually majoring in physics. I then went to McGill University in Montreal, Canada, earning a doctorate in atmospheric sciences. A year later, I came to Goddard as an atmospheric scientist.

Living in four countries gave me a variety of experiences and professional interactions. Not only is my lab international, but the research and science communities at large are international as well.

 
Why did you become an atmospheric scientist?

I was always interested in the mysteries of weather. Every day changes fascinated me. Seasons intrigued me. As an undergraduate, I met some professors who were atmospheric scientists and they encouraged me to do extra work to delve deeper into the topic. I also thought that job prospects were better for an atmospheric scientist than for other disciplines in physics.

Conversations with Goddard - Lazaros Oreopoulos

Lazaros Oreopoulos. Photo by W. Hrybyk (NASA).

What was your proudest moment at Goddard?

My proudest day was the day I was deemed worthy to lead a lab. I was excited and intimidated at the same time.

What do you do outside Goddard?

I like listening to indie rock music, which is contemporary rock outside the major label circuit. My combined physical and digital music collection exceeds 5,000 albums. I tried playing guitar, but wasn’t very good at it. I’m now encouraging my young son to learn for both of us.

As a mentor, what advice to you give?

Within my laboratory, I personally work with five young scientists who help advance my research projects. I urge them to be passionate about the science, come up with original ideas and work hard.

I also tell them it is very important to learn to communicate their science effectively. I advise them how to get their message across in their writing and oral presentations. You first have to believe in your research project, that’s the start of being appealing as a scientist. Not everyone is very charismatic, you either are or you’re not, but you can learn to overcome a charisma deficiency. Everyone can learn to effectively communicate their science. I try to teach them to be concise and highlight what is important. I encourage them, as well as others in my lab, to attend workshops on how to present and write better.

What is the one thing you would tell someone just starting their career at Goddard?

I’d tell them that they are in one of the best places in the world to work in science and engineering. I’d tell them to focus on the fun and exciting aspects of their work and not worry about small, daily issues. Minor problems don’t change the fact that we are at Goddard and lucky to have this opportunity. So, I’d remind them to always focus on the big picture and what matters most.

What is it like being married to another researcher?

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This astronaut photograph shows much of the nation of Greece. The Peloponnese—home in ancient times to the city-state of Sparta—is the great peninsula separated from the mainland by the narrow isthmus of Corinth. Read more about this image here.

My wife is an M.D.-Ph.D. at the National Human Genome Research Institute of the National Institutes of Health. We occasionally discuss our respective research. Since we are both scientists, we understand each other’s work demands and that there will be periods of intense work where we need to support each other. We have one child still at home so we have to creatively juggle caring for him along with our other domestic responsibilities. Every year we struggle to find mutually available days to take a family vacation. My wife was also born in Greece, so we try to go back to Greece every year. We are glad to see that our son is also showing an inclination towards mathematics and science, but will of course let him choose his own path.

This interview was originally published by Goddard Space Flight Center. 

January Puzzler Answer: Palau’s Coral Reefs

February 18th, 2016 by Adam Voiland

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Congratulations, Thomas Goldammer, for being the first to solve our January Puzzler. As Thomas noted, the image highlighted coral reefs immediately north of Palau’s Babeldaob island. Tyler Johnson chimed in the next day with some additional details and insight.

Though more than 100 people weighed in on Facebook, reefs in Palau never came up. Interestingly, several Facebook readers guessed that the image showed reefs in the Maldives. That, in turn, reminded me of an old but excellent story in our archives about the amazing atolls in the Maldives. The story does a nice job of explaining how atolls (such as the the North and South Malosmadulu Atolls shown below) get their remarkable shapes.

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As our atoll article explains, the shapes of Maldavian atolls are affected not only by the birth and death of islands but also by the churning and currents of the ocean caused by the winds of passing monsoons. (Extraordinary, isn’t it? Maybe it is just me, but I find understanding how the land surfaces came to be both fascinating and humbling.)

Getting back to Palau, I also want to draw your attention to the video below. Compiled by the Khaled bin Sultan Living Oceans Foundation, it shows mesmerizing aerial and underwater imagery of Palau’s reefs. In fact, the foundation recently completed an expedition to Palau to collect baseline data on the health of the reefs. Ground campaigns like this—combined with aerial and satellite campaigns from above—offer scientists a more  complete picture of the health of the world’s coral reefs than either might along. To learn more about a NASA-sponsored aerial survey of Palau’s coral reefs, see our January 31 Image of the Day.

Ground to Space: Antelope Island, Utah

February 9th, 2016 by Adam Voiland
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Photo by Ray Boren. Image first published by Earth Science Picture of the Day.

Technically, there are not any antelope on Utah’s Antelope Island, the largest island in the Great Salt Lake. Rather, some 200 pronghorn (which fill a similar ecological niche as their Old World counterparts) and 300 mule deer live on the island in the southern part of the lake.

Despite the name (attributed to explorers John Frémont and Kit Carson), Antelope Island is perhaps best known for its free-ranging bison herd. Four breeding pairs were introduced to the island in 1893, a period when hunters had pushed bison toward extinction across much of North America. The lack of trees and abundant grass made the 24 kilometer (15 mile) long and 8 kilometer (5 mile) wide island ideal habitat for the largest land animal in North America. Now, park managers have to remove a few hundred bison every year to keep the population at sustainable levels (between about 500 and 800). See the video below, produced by the Salt Lake Tribune, to learn more about the island’s annual bison roundup.

The landscape and geology of Antelope Island offers much of interest as well. The island is comprised of several different rock formations that represent a range of geological processes. The oldest rocks on the island—gneiss, a coarse-grained, irregularly banded metamorphic rock—formed between two and three billion years ago when sedimentary rocks such as claystone and siltstone were squeezed under extremely high temperatures and pressures. The island’s youngest rocks (tufa limestone) formed when calcium carbonate precipitated from Lake Bonneville about 10,000 to 15,000 years ago.

Ray Boren, a photographer and retired journalist, stopped by the island on December 23, 2015. “I love to go there when I’m out and about,” Boren said in an email. “It is a wonderful rural setting within shouting distance (well, not quite) of the millions of people living along Utah’s Wasatch Front.”

It was a chilly, windy day. “I’ve come to see what’s happening on the island,” Boren told a worker at the park entrance. “You mean, besides the wind?” she replied. Indeed, strong prevailing winds out of the northwest and west were whipping loose snow across the causeway and the island roads, creating intermittent drifts and icy conditions. Even more dramatic was the effect on the island’s shores, benches, plains and mountainous central ridge.

In the photo at the top of the page, originally published by Earth Science Picture of the Day, snow streamed through a boulder field on the island’s northeast side. “The Sun is beginning to set, and the light’s low angle and longer wavelength colors help tint the scene. In the photograph below, snow is being stirred in ephemeral waves, swirls and columns off the jagged terrain of Frary Peak, the island’s highest point at 6,596 feet (2,010 meters).”

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Photo by Ray Boren. Image first published by Earth Science Picture of the Day.

For a different perspective on Antelope Island, I dug into the Earth Observatory archives for the images below. Acquired by the Multi-angle Imaging SpectroRadiometer in 2001, the pair offers a winter and summer view of the island. In addition to the obvious difference in snow cover, note the contrasting water color in the northern and southern part of Great Salt Lake. The different colors are the result of a rock-filled causeway built in 1953 to support a permanent railroad. The causeway decreased circulation between the two arms, producing higher salinity on the northern side. If you look closely at the full resolution image, you should be able to see the causeway connecting the island to the mainland.

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The winter image (left) was captured by the Multi-angle Imaging SpectroRadiometer on NASA’s Terra satellite on February 8, 2001. The summer image (right) was captured by the same sensor on June 16, 2001.

January Puzzler

January 25th, 2016 by Adam Voiland

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Every month on Earth Matters, we offer a puzzling satellite image. The January 2016 puzzler is above. Your challenge is to use the comments section to tell us what part of the world we are looking at, when the image was acquired, what the image shows, and why the scene is interesting.

How to answer. Your answer can be a few words or several paragraphs. (Try to keep it shorter than 200 words). You might simply tell us what part of the world an image shows. Or you can dig deeper and explain what satellite and instrument produced the image, what spectral bands were used to create it, or what is compelling about some obscure speck in the far corner of an image. If you think something is interesting or noteworthy, tell us about it.

The prize. We can’t offer prize money, but, we can promise you credit and glory (well, maybe just credit). Roughly one week after a puzzler image appears on this blog, we will post an annotated and captioned version as our Image of the Day. In the credits, we’ll acknowledge the person who was first to correctly ID the image. We’ll also recognize people who offer the most interesting tidbits of information about the geological, meteorological, or human processes that have played a role in molding the landscape. Please include your preferred name or alias with your comment. If you work for or attend an institution that you want us to recognize, please mention that as well.

Recent winners. If you’ve won the puzzler in the last few months or work in geospatial imaging, please sit on your hands for at least a day to give others a chance to play.

Releasing Comments. Savvy readers have solved some of our puzzlers after only a few minutes or hours. To give more people a chance to play, we may wait between 24-48 hours before posting the answers we receive in the comment thread.

Good luck!

Update: The answer is posted here. The winners and more details are highlighted here.

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(Image by NASA Earth Observatory)

Though blizzards and cold snaps may have made you forget the news from last week, 2015 was the warmest year in NASA’s global temperature record, which dates back to 1880. During a January 2016 press conference (see the slides here), Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies, explained that 2015 was 0.87 degrees C (1.57°F) above the 1951-80 average in the GISS surface temperature analysis (GISTEMP), one of four widely-cited global temperature analyses.

The statistical record is notable, but keep in mind that this year is just part of a much longer story about the climate. If you want to learn more about climate science as a whole rather than just the latest headlines, here are a few resources that you may find informative. The list is not comprehensive (and we are open to more suggestions), but it is a useful starting point for understanding climate science.

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(Image by Eric Roston and Blacki Migliozzi for Bloomberg Business)

The plot above comes from an interactive graphic called “What’s Really Warming the World?” Put together by Eric Roston and Blacki Migliozzi of Bloomberg News (with assistance from NASA climatologists Gavin Schmidt and Kate Marvel), the chart does an excellent job of breaking down the various factors (greenhouse gases, aerosols, solar activity, orbital variations, etc.) that affect climate. It parses out visually how much each factor contributes. The bottom line: greenhouse gases are absolutely central to explaining global temperature trends since 1880. The screenshot above hints at what the interactive looks like, but I highly recommend heading over to Bloomberg to see the full graphic.

Another invaluable graphic for understanding climate change is the “radiative forcing bar chart” below. (You can read an interesting post by Schmidt that explains how these charts have evolved over the decades). At first glance, the chart from the fifth assessment report by the United Nations’ Intergovernmental Panel on Climate Change may seem technical and difficult to understand. It is. But it is well worth looking up the technical terms.

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(Image by the IPCC for the WG1AR5 Summary for Policy Makers)

In short, you are looking at a balance sheet of the major types of emissions that have either a warming or cooling effect on climate. Bars that extend to the left of the 0 signify a cooling effect; bars that extend to the right signify warming. The longer the bar, the more warming or cooling a given type of emissions contributes. What becomes immediately obvious is that carbon dioxide (CO2) and methane (CH4) have the biggest warming influence by far. The other well-mixed greenhouse gases — halocarbons, nitrous oxide (N20), chlorofluorocarbons (CFCs), and hydrochlorofluorocarbons (HCFCs) play a much smaller role.

The situation gets messy when you look at the role that short-lived gases and aerosols play. Some gases like carbon monoxide (CO) and the non-methane volatile organic compounds (NMVOC) — such as benzene, ethanol, formaldehyde — contribute to warming, but not much. Others like NOx actually slightly cool the climate overall if you consider how these gases interact with other substances in the atmosphere. Things get even messier if you look at aerosols. Mineral dust, sulfate, nitrate, and organic carbon have a cooling effect. On the other hand, black carbon causes warming. Albedo changes due to land use and changes in solar irradiance are minor in comparison to the other factors.

That’s a lot of variables, but one reason I like this chart is the error bars and the “level of confidence” column. The error bars give you a sense of how much uncertainty there is when it comes to the effects of various emissions. Look at the aerosol section, for instance, and you will see that the error bars are quite large and there is still some uncertainty about how aerosols affect clouds. The level of confidence column offers further clues to what scientists understand well and which areas they are less confident about. VH stands for very high confidence; H stands for high confidence; M stands for medium confidence; and L stands for low confidence.

What is striking is that even when you account for the error bars, there is little doubt that carbon dioxide and methane are warming the climate.

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(Image by the NASA Global Climate Change website)

A third graphic, produced by NASA but based on data described here, is particularly compelling. Based on atmospheric information preserved in air bubbles in ancient ice cores, the plot offers a view of carbon dioxide levels in Earth’s atmosphere for the past 400,000 years. As this graph makes obvious, it has been a long time since carbon dioxide levels have been anywhere near where they are now.

For a much more recent view of carbon dioxide levels, the animation above is useful. Produced by NASA’s Scientific Visualization Studio, the video shows a time-series of the distribution and concentration of carbon dioxide in the mid-troposphere, as observed by the Atmospheric Infrared Sounder (AIRS) on the Aqua spacecraft. For comparison, the fluctuations in AIRS data is overlain by a graph of the seasonal variation and interannual increase of carbon dioxide observed at the Mauna Loa observatory in Hawaii. You can clearly see seasonal variations in carbon dioxide levels, but notice also that the mid-tropospheric carbon dioxide shows a steady increase in atmospheric carbon dioxide concentrations over time. That increase is because of human activity.

Image by Harvard University Press.

(Image by Harvard University Press)

My last recommendation will take longer for you to get through, but it is an invaluable resource. Physicist Spencer Weart offers a detailed but understandable account of the history of climate science research in his book The Discovery of Global Warming. You can read an extended version of book online on the American Institute of Physics’ website. If you make it all the way through, you will know far more than most people about the climate.