Reflections at the top of the world
It was 11:30 in the morning and GLISTIN-A instrument engineer Ron Muellerschoen and I were in northern Greenland at the Thule Air Base pier looking over the frozen Wolstenholme Bay. We’d been talking about the time Ron was wearing shorts here during the summer, but today it was the typical -22 Fahrenheit (-30 Celsius.) And even though over the past week we’d somehow gotten used to the cold and I was wearing a big parka, my legs were starting to get cold after walking for an hour. So we decided to head back.
As we turned around to go, I was struck in the face by the sun’s rays reflecting off the ice-covered ground. The brightness was astounding. And in that instant the meaning of “albedo” was seared into my brain in a way that went beyond reading about the science or looking at illustrations and animations.
There was something special about the experience of having the rays of the sun, which was sitting low in the high latitude sky, hit the ice surface at that extremely low angle and reflect off into my eyes.
Albedo is a measure of how reflective a surface is, how much light energy bounces off and reflects away and how much light energy gets absorbed. (Think hot asphalt on a sunny day. Black asphalt has a low albedo and absorbs light energy, while the brightest white has the highest albedo and reflects the light.)
I stood for a moment, looking at the ground — a hard, dry, crusty mixture of ice and snow that made an exceptionally satisfying crunch crunch noise as our boots marched through it — and tried to figure out the color: 50 shades of white. I settled on white/light blue/silvery sparkle. Due to the low angle of the sun, the tiniest rough edge the size and shape of a pebble on the ground’s textured surface left a long, dark shadow.
No matter where we were or how we stood or what time of day, all day, every day, there were always long shadows — crazy long shadows. At 78 degrees north latitude, a full 12 degrees above the Arctic Circle, the sun will never be overhead. Never. I know that seems unbelievable, but even during the summer solstice, when Earth’s North Pole is tilted toward the sun, or during the four summer months of 24-hour daylight, the sun is always low, low, low at this latitude.
Low on the horizon
In that moment, I also understood another science question that had been bothering me. I’d been wondering why the meter-thick sea ice hadn’t yet begun to melt. Even though it was the end of March, even though the equinox had passed, the sun was out and the days were getting longer. In fact, up here the days were getting much longer, very quickly. On March 23, just three days after the equinox, we were already having 14-hour days with sunsets lasting past 9 p.m. That’s because in these high latitudes, the day length can increase by as much as 40 minutes per day. And by mid-April, just a few weeks after spring equinox, there will be 24 hours of daylight and the sun won’t set again until September.
By mid-April the meter-thick layer of frozen seawater that covers the sea surface and fills the fjords will completely melt and expose the dark blue ocean underneath. But today, even in this brilliant sunshine, even on this day of 14-hour sunlight, the ocean was still completely frozen over.
But “Why?” I’d been wondering. Why, with all this extra sunshine, was the sea surface still so frozen? And why did that hard, dry, crusty mixture of ice and snow still remain on the ground?
In that instant, as the glint of the sunlight reflecting off the icy ground hit my face, I knew exactly why. It was the extraordinarily low angle of the sunlight that bounced right off the stunning bright whiteness of the ice. The sunlight was not absorbed by the ice and snow and instead was reflected away. It wouldn’t be until another month or so that the sun would get a little higher in the sky. And although the sun would never be directly overhead up here, it would be high enough to begin melting the ice.
No matter how much a person studies Greenland, or the northern latitudes, or albedo, or Earth in general, going into the field to experience those things can change your entire understanding of the world and how it works. I stood there for a moment, just allowing the high-latitude sun’s cold rays to glance off the snowy ice and shine straight into my face.
NASA’s Oceans Melting Greenland (OMG) team is here in Greenland; here to find out specifically how much ice the island is losing due to warmer ocean waters around the coastline. There is almost no ocean data in remote places like this, but OMG is busy working to change that, studying the complex ocean processes that affect Greenland's coastline because gathering data is critical to understanding Earth’s complex climate. This information will help us understand the amount of sea level rise we're going to have around the world.
Thank you for reading,
Dive into a sea of Oceans Melting Greenland data
"Get to work." The phrase stuck in my head.
I had just walked out of a two-and-a-half-hour debriefing with NASA’s Oceans Melting Greenland (OMG) Principal Investigator Josh Willis, but the whole meeting could be summed up in those three little words of his: Get to work.
It was as though he’d been ringing one of those big ol’ dinner gongs. Data! Hot off the press! Come and get your data! Calling all oceanographers, geologists, paleo-climate scientists: come and get a big ol’ helping of free data.
He made me hungry for data, too.
OMG has just returned from its second spring season. Every April for five years, just before the ice starts to melt, OMG flies a radar instrument over almost every glacier in Greenland that reaches the ocean and collects elevation measurements within a 6.2-mile (10-kilometer)-wide swath for each glacier individually so we can measure how quickly each one is thinning. That’s literally hundreds of glaciers.
“We have more than 70 of these swaths that cover a couple hundred glaciers to create new elevation maps that are high accuracy, high resolution and high quality,” Willis said.
OMG also has bathymetry data from sonar and gravimetry. And we have a year’s worth of Airborne Expendable Conductivity Temperature Depth Probes AXCTD data collected last September plus hundreds of vertical profiles of temperature and salinity taken from ship surveys. “We have temperature measurements in many glacial fjords that have never had a historical temperature profile before. And none of that data is being used to its fullest extent yet.” OMG will set the baseline so we know what the water temperatures are today, and as we look to the future, we can watch them warm. That’s huge.
I recounted all the times I’ve told someone that many parts of the ocean are still so unknown. I thought about all the times I’ve written about the OMG aircraft flying into remote, uncontrolled airspace, or researching the ocean water-ice interface around Greenland: So many of these places still nameless, still anonymous, still unidentified, still unknown. It’s mind blowing.
And somewhere in all this new data is information about the correlation between the ocean water and the ice as well as the answer to the question of how each glacier may or may not be affected by the waters offshore. “We know that warm water reaches a lot of glaciers. And there have been surveys in few places, but we’ve never had a comprehensive survey of the shelf water before,” Willis said.
OMG is mapping out the edges of glaciers and watching them change year on year on year. The mission measures glacial elevation in the last few kilometers before the glacier hits the water to see exactly how much the glacier shrank or retreated or both. In a few cases, the opposite might happen. Over a single year, a glacier might not have had as much calving or it might have slowed down, which would cause it to thicken and advance.
There are literally hundreds of glaciers to research and dozens of papers buried in that data. And anybody who wants to can sift through it and publish. “You could get a Ph.D. done really fast,” Willis added enticingly. Here are some recommendations for interesting scientific research:
- OMG’s temperature data could be used to write oceanography papers about where the warm water is on the shelf and to map out and catalogue which glaciers terminate in deep Atlantic water and which ones sit in shallow water. OMG has enough data to catalogue the depth of the faces of two-thirds of the glaciers around Greenland.
- Paleo-climatologists and geologists can use new clearly mapped-out OMG bathymetry data to study how ancient glaciers carved troughs in the sea floor. Looking at maps of the seafloor will help us understand the implications for Greenland’s ancient ice sheet. Some flat-bottomed troughs, for example, show evidence of where little ancient rivers must have carved their way through to erode the paleo-glaciers. And sea floor sediments could be analyzed to find out how far the ancient glaciers advanced.
- Overview papers that compare and contrast the east, west, north and south coasts of Greenland would be incredibly useful to have.
- Some elevation maps made from historical datasets as well as a few decades’ worth of temperature measurements already exist for some isolated regions across Greenland. Using these historical maps, it’s now possible to compare them with current measurements of temperature and elevation in these locations to observe the changes.
- OMG is also gathering oceanography data around Greenland. Since the Atlantic Ocean water is very warm and salty and the Arctic Ocean water is cold and fresh, the ratio of those two could be analyzed. Warm Atlantic Ocean water has been in the coastal area around Greenland forever, but how much Atlantic water makes it onto the shelf and reaches the glaciers? This is affected by the bathymetry and the winds, which affect the local currents. And according to Willis, “There’s really still a lot to learn.”
Already there are four downloadable datasets right here! So, come and get it, all you hungry Ph.D. oceanographers.
Get to work.
I can't wait to read your papers,
Baffin Island, specifically, the largest island in Canada.
“What are we doing all the way out here?” I thought. If I looked out the left side of NASA’s modified G-III aircraft, I could see Canada out the window—Baffin Island, specifically, the largest island in Canada, part of its northeast territory. And if I looked out the right side, I could see the west coast of Greenland. We were pretty much halfway between the two, right in the middle of Baffin Bay, and I was surprised.
At a glacial pace
I went over to where Flight Engineer Terry Lee kept the map of all the scheduled drop positions and stared at it for a while. She’d marked with a green highlighter the places where she’d already released science probes through a tube in the bottom of the plane. (Hahahah, yes! There’s a hole in the plane through which Aircraft eXpendable Conductivity Temperature Depth (AXCTD) probes leave the aircraft to travel 5,000 feet down to the sea surface and then another 1,000 meters into the ocean, sending back data as they go.)
I looked out the window as we flew on. Icebergs dotted the seascape. Each one had once been part of a vast ice sheet that’s been around for hundreds of thousands of years. Each one had moved – at a glacial pace, mind you – from the interior, down through one of the many fjords that slice through the Greenland coastline, and finally out to sea, where they would ultimately melt away. The ‘bergs were large, and it was fun to fly over them and look at their perfect whiteness against the stunning blue sea. All of us would gather on one side of the plane as we passed over a ‘berg, and then quickly jump to the other side to look for it again as we passed by it. But even though there were hundreds of icebergs floating around out there, Baffin Bay is vast — more than 250 thousand square miles. So, in the grand scheme of things, the icebergs seemed inconsequential, incapable of affecting the ocean salinity more than a small amount.
As I was listening, I could see temperature and salinity values arriving in real-time on the monitor. “Wow, no way!” I exclaimed. “That’s insane.” All the way in the middle of Baffin Bay, 100 miles offshore, the ocean was fresher on the surface. I watched the salinity values increase as the probe sank. The temperature profile also reflected a scenario of near-zero-degree water at the surface with 3- to 4-degree ocean water below. That upper layer is Arctic Ocean Water, which is way less salty than the warmer North Atlantic Ocean Water that lies beneath it.
I walked back to look at the yellow dots on the map of the scheduled probe drops one more time. We were as far away from the coast as we would be; the rest of the drops were closer to shore. I wondered how the temperature and salinity profiles in the coastal waters would compare to those from the open ocean.
And the point of the mission flooded my mind again. I looked out the window, across the stretch of Baffin Bay at the Greenland coastline, where groups of icebergs dotted the horizon. In this vast expanse, no one’s done this before, no one knows what this ocean water is like, and we are about to find out.
Find out more about Oceans Melting Greenland.
View and download OMG animations and graphics.
Thank you for your comments.
Greenland is one of the few places that’s harder to get to than outer space
I’m going to Greenland. I told my brother, and he replied, “Oh cool, I’m headed to Ireland.” That’s the typical response, as if Greenland were just some place one could book a ticket to, with commercial airports, and hotels, and restaurants and stuff. But … no, Greenland is different. It’s actually not an independent country, for example. (It’s a territory of Denmark.)
The other response I keep getting is that dumb, corny comment about it not being green. So it seems like the only thing we collectively understand about Greenland is that it’s a place to go and it has a hypocritical name.
But that is just so wrong. My husband and I finally got on the same page this morning when he opened the Google Maps satellite view of Kangerlussauq Airport, where I’m scheduled to land. “Oh,” he said. “It’s a barren dirt strip in the middle of nowhere and nothing.”
At last, an acknowledgement of the truth. The only place that’s harder to get to than Greenland is outer space. I know that sounds funny, but I’m not even kidding. (Okay, okay, Antarctica is also hard to get to, along with the Marianas Trench. Ugh.)
I first became aware of how little we know about Greenland when I was creating NASA’s Global Ice Viewer for our climate website. I found shots from Alaskan glaciers that dated all the way back to the late 1800s for the gallery. Gents with top hats and ladies in bustles with Victorian cameras stood on the ice. But Greenland? Photos taken before the 1980s are extremely rare.
And while most people understand that increased atmospheric temperatures have been melting the ice sheet from above, global warming has also been increasing ocean temperatures. And this means the ocean waters surrounding Greenland are also melting the ice sheet from around its edges.
Which is the reason I’m headed up there with NASA’s Oceans Melting Greenland (OMG) campaign in the first place: to measure the temperature and salinity of those unknown waters. See, the fresh water that flows into the ocean from ice melt is about 0 degrees and less dense, so it floats right at the sea surface. The North Atlantic Ocean Water is about 3 or 4 degrees, salty and denser, so it sits right below the fresh melt water. And these two waters don’t really mix much. When the 3- or 4-degree North Atlantic Ocean Water gets in contact with Greenland’s ice sheet, it’s warm enough to melt it.
But no one knows the melt rate yet. No one.
Even though Greenland’s melting ice sheet impacts each and every one of us right now. The rate of ice melt will determine how much sea level rise we’re going to get, 5 feet or 10 feet or 20, everywhere, all over planet Earth, not just in Greenland, but at coastlines near you and me.
This is where that whole NASA “exploring the unknown” theme comes in. Next week, the OMG team (including yours truly) will be in Greenland on NASA’s G-III aircraft. We’ll spend five weeks flying around the entire coastline, measuring the salinity and temperature of the coastal waters by dropping 250 Aircraft eXpendable Conductivity Temperature Depth (AXCTD) science probes through a hole in the bottom of the plane. The reason we’re going in September is that’s the warmest time of the year in the ocean, the ice will reach its lowest extent and we’ll be able to measure as much of the coast as possible. The plan is to repeat the same mission for five years to find out what the melt rate is and how much that rate is increasing.
Am I excited? Yes, beyond. Aside from the science preparation, it took months and months of personal prep. I passed a Federal Aviation Administration medical exam, then got trained in First Aid, CPR, AED, hypoxia, disorientation, survival, and hearing conservation, and then had to buy steel-toed shoes, which are required to fly on that NASA plane. Today, I am psyched beyond belief.
Why else would anyone work so hard to do something? Just like the rest of the team, I hope our work really makes a difference.
We know more about the moon and other planets than we do some places on our home planet. Remote parts of the world ocean remain uncharted, especially in the polar regions, especially under areas that are seasonally covered with ice and especially near jagged coastlines that are difficult to access by boat. Yet, as global warming forces glaciers in places like Greenland to melt into the ocean, causing increased sea level rise, understanding these remote places has become more and more important.
This past spring, Oceans Melting Greenland (OMG) Principal Investigator Josh Willis led a team of NASA scientists to begin gathering detailed information about the interface between Greenland’s glaciers and the warming ocean waters that surround them. The next step in accessing this extremely remote region involves dropping a series of Airborne Expendable Conductivity Temperature Depth, or AXCTD, probes that will measure ocean temperature and salinity around Greenland, from the sea surface to the sea floor. With this information, they hope to find out how quickly this warmer ocean water is eating away at the ice.
Since no one has ever dropped AXCTDs through a tube at the bottom of a modified Gulfstream-III, the OMG team headed to Ellington Field Airport near NASA’s Johnson Space Center in Houston, Texas, for a test drop into the Gulf of Mexico. I went along for the ride.
The money shot
Temperature and salinity
3, 2, 1 ... drop!
AXCTD sails down
The flight path
Details, details, details
Find out more about Oceans Melting Greenland.
View and download OMG animations and graphics.
Thank you for your comments.
Think back to when you were a kid imagining what you were going to be when you grew up. You dreamt that someday, somehow, you would make a difference, a contribution, that your work would be meaningful in the world. If you accomplished this today, how pumped would you be?
"This is going to sound really cheesy and lame," NASA oceanographer Michelle Gierach told me over a Skype call from COP21 in Paris, "but I just get a sense of pride being from the U.S. and being a cool NASA representative and seeing people get excited about what we do. In my day-to-day job, I sometimes forget how much Americans and international people from everywhere love to know what we're doing. It reinvigorates a sense of pride in NASA's work."
Because of the nine-hour time difference, I was barely awake for our call, and through my morning mental blur I wondered for a moment if the glee in her voice had something to do with the fact that I'm a fantastic person and she was thrilled to be speaking with me, or perhaps she was hopped up on chocolate. "They give you chocolate bars every day!" she squealed. "I'm not lying, and it's really good chocolate."
But it was the conference, COP21, the 21st Conference of the Parties of the U.N. Framework Convention on Climate Change, that had her all giddy. You see, after so many years of stagnation, resistance and even moving backwards, finally, finally there seems to be movement toward global action against climate change. Yes, it's baby steps, and yes, there's more work to do, "but some movement is significant," she stressed. "I'll take it."
All of us are hungry for something positive. Always. Especially now, since most of the news lately has been such a total bummer. A positive message around climate could be that bump in optimism that we all need right now.
The U.N. COP21 meeting in Paris began on Nov. 30, and by this Friday, Dec. 11, 195 member nations hope to reach a unanimous agreement to cut greenhouse gas emissions, hold global warming to 2 degrees Celsius or even lower and provide financial support to developing nations so they can bypass fossil fuels.
It's hard not to feel optimistic. Part of you wants to get your hopes up, but you also don't want to be disappointed, because for so many years there's been so much disappointment. Then there's that part of you that says, This time is different. This time we can do it. Gierach told me that she felt an energy about reaching an outcome at COP21. The overall vibe is "completely optimistic, everybody wants to do something, everybody knows we have to do something. There's a 'let's do it' kind of attitude."
Hyper about the Hyperwall
Last week, we'd spoken about her upcoming trip. She had conflicted feelings due to the recent events in Paris and was concerned about a heightened state of worry and icky vibes. "As a NASA representative," she explained, "my role is to show what NASA is doing with regards to climate change, even though I'm not a delegate or a policy maker. I was so excited to go, and now I'm just not so excited about it anymore." But what a difference one week and a few thousand miles made. From the conference her voice sounded triumphant: "Everybody here wants to show that it's not going to stop what they're trying to do here. It hasn't stopped it at all."
Gierach also told me she was, "super excited that this time around it finally seems people are listening. People see that the oceans are part of a massive system and actually are a significant reason we haven't had a more extreme temperature rise. That message seems to be getting out there." She's been talking about the oceans every day on NASA's hyperwall, an ultra-high resolution visualization that combines nine computer monitors into a giant screen that plays animations in tandem.
On Dec. 3, she joined a panel called "Oceans under pressure" to discuss the following main points of consensus that we can see from satellites:
- The sea surface temperature record shows that the ocean is warming, which clearly impacts Arctic sea ice reduction, the different types of sea ice, and ice sheet reduction.
- Sea level rise is not equal around the globe; for example, the western tropical Pacific has much higher sea level rise than the eastern equatorial Pacific.
And because a significant portion of the conference is dedicated to carbon emissions, she's also talking about the interaction between the ocean and the atmosphere and how carbon dioxide transfers between the two.
Just before we hung up, she added, with power in her voice like a chant or rally call, "Yeah, we're here and we're going to do something. We're not just speaking; we're actually acting and showing that we're acting."
Watch the live stream from the U.S. Center at COP21 in Paris here.
Watch the "Oceans Under Pressure" panel with panelists Jean-Pierre Gattuso, IDDRI/CNRS; Jean-Pierre Gattuso, IDDRI/CNRS; Alexander MacDonald, NOAA; Michelle Gierach, NASA; Cassandra deYoung, FAO here.
Thank you so much for reading,
P.S. Michelle was totally inspired by President Obama's speech and said, "Regardless of what people may think, he is trying to make the world a better place. It made me extremely proud to be part of the United States and have him as our president." Watch the speech here.
Bring out the trumpeters! We’re preparing for another satellite launch. Woohoo! This time it’s Jason-3, an altimetry mission that will observe sea surface topography from space. It’s a legacy mission that continues the 23-year record of global sea level measurements started by TOPEX/Poseidon and carried on by Jason-1 and -2.
When I think of the word “legacy,” I normally become all melancholy ‘n’ stuff, because the word reminds me of what I was doing when those previous satellites went up and of all the people, science and stories that have influenced my life since. So this morning, on my drive to work, I tuned in to a '70s music radio station to funky disco my way out of my melancholy funkiness. (Take that, '80s music heads!)
But no, really, TOPEX/Poseidon was totally cool. (The acronym “TOPEX” comes from “TOPography EXperiment” and Poseidon is the Greek god of the sea; “Jason” is from Jason and the Argonauts, also from Greek mythology.) It launched in 1992 and was the first revolutionary precision oceanography satellite. It transformed the way we study the ocean, because the view from space is the only way to truly observe the vastness of the ocean on a global scale. Since TOPEX/Poseidon began collecting data in 1993, global sea level has risen 80 millimeters. That’s 3 inches in just over two decades. Holy moly! Now you see why it’s so important to have an uninterrupted stream of satellite data that extends far into the future.
Before TOPEX/Poseidon, there was Seasat, which was designed to find out if global satellite monitoring of Earth’s ocean was even feasible. It launched in 1978 and operated for just over 100 days. And yupity do dah, now we know that satellite observations are feasible.
Just like its predecessors, Jason-3 is a radar altimeter, an instrument that measures sea surface height by precisely knowing the satellite’s position in its orbit and by measuring the distance between itself and the top of the ocean. You see, the ocean surface is constantly changing, from waves, to tides, to El Niño, to sea level rise. As increased global warming causes more and more glacial ice and ice sheets to melt into Earth’s ocean, and as this same warming heats the ocean surface, causing the warmer water to expand and sea levels to rise higher, it’s absolutely crucial to have highly accurate, continuous global sea level measurements.
Furthermore, since the majority of Planet Earth is covered by ocean, and since water is exceptionally good at storing heat, the ocean will continue to play an enormous role in Earth’s long-term climate.
Jason-3 will launch from Vandenberg Air Force Base in July or August. I’ll be keeping you up-to-date on all of the goings on about the launch and its preparation. Meanwhile, you can find out more about Jason-3 and all of NASA's ocean surface topography missions here:
I look forward to your comments.
Jason-3 is an international partnership led by the National Oceanic and Atmospheric Administration with participation from NASA, France's Centre Nationale d'Etudes Spatiales (the French space agency) and EUMETSAT, the European Organisation for the Exploitation of Meteorological Satellites. JPL built Jason-3's radiometer, GPS and laser reflector; is procuring the launch; and will help oversee the science team, which is responsible for ensuring the quality of the data.
I visit the NASA website and review the data. CO2: Up. Ocean and land temperature: Up. Sea level: Up. Polar ice: Down.
But, as bizarre as this sounds ... I find myself pulling for the climate change deniers. Wouldn't it be swell if they were right? We could all just relax and ride around in huge cars, and life would be good again.
Like it was in 1970 when I showed up at the first Earth Day. Oh, wait. The smog kind of sucked back then. That might not be the best example.
But, what about the main reason the deniers give not to address climate change?: The cost.
As it turns out, a great example can be found back in smoggy Los Angeles in 1970. Many of us wanted to do something about the horrible choking smog of that era. But, we were told we couldn't afford it.
"We'd love to do something too, Ed, but ... the cost!" Fortunately, we didn't listen to them. Fortunately we also weighed healthcare costs and lost productivity into the equation, and realized the cost of doing nothing was much greater.
And, now, even though we have millions more people in L.A., and four times the cars ... we have far less smog. And, there were many jobs and tremendous wealth created by doing the things that addressed the problem.
Making catalytic converters, combined cycle gas turbines, spray paint booths, and a myriad of other clean technologies of that day - they all created new industries, and brought growth with them.
We have that same choice today. Do we want to accept the costs of doing nothing, and hope that the problem goes away?
So, please, do as I do, and direct everyone you know to reputable sources of climate data, such as NASA's Global Climate Change website. At every talk I give, I make sure that everyone is aware that this information if available. The clock is ticking, and to ignore the science on this one is the worst bet we have ever placed.
Ed Begley Jr. is an Emmy-nominated actor who is active in the environmental community and turns up to Hollywood events on his bicycle. He currently lives near Los Angeles in a self-sufficient home powered by solar energy.
My wife likes to gamble. She's no high roller or anything, but give her a hundred dollars, a spare weekend and a room full of slot machines and she's happy.
Not me, though. Somewhere along the way, I guess I took one too many math classes and betting against the house just isn't much fun anymore.
But I understand why she likes it. It's the ups and downs of gambling that are fun. You lose, lose, lose and then every once in a while you win a great big jackpot. Maybe you even win enough to make up for the last 30 or 40 bets you lost. But like any game in the casino, the odds are stacked against you. If you play long enough, you will eventually lose.
Global warming and climate change work in much the same way. Wait long enough and odds are, the Earth will be warmer. But will tomorrow be warmer than today? Who knows! There are plenty of things about the atmosphere and ocean that can't be predicted. Over a period of days or weeks, we call these unpredictable changes "the weather."
No one can predict the weather more than a few days in advance, any more than they can predict which slot the roulette ball will land in before the croupier spins it. Weather, like roulette, is essentially random.
But a little randomness doesn't stop casino owners from taking your bet at the roulette table. They know the odds, and they know if enough bets are laid they will eventually come out ahead. Climate scientists know that, too.
Random events happen in the atmosphere and oceans all the time. Not just the weather, but things like El Nino, La Nina and huge volcanic eruptions can make the planet warm up or cool down for years at time. There could even be a few others that we haven't discovered yet.
Still, for all its short-term ups and downs Earth's average temperature has risen dramatically over the last one hundred years. That's no accident. Like the house edge at the roulette table, human-made greenhouse gasses have tilted the odds in favor of a warming planet.
Sometimes it's easy to forget that fact when new science results come out. Like the recreational gambler, we often find it more fun to focus on the ups and downs: a short-term cooling period, a warm year during a big El Nino.
But for climate change and casino owners, it's important to remember the big picture. The roulette player might win three or four bets in a row, but that doesn't change the odds. Eventually the casino will win. Likewise, as long as humans continue to add carbon dioxide to the atmosphere, the planet will continue to warm.
So whenever people ask me about the latest warming or cooling in the climate record, I'm always reminded of my wife and her slot machines. By the end of the weekend her hundred dollars is almost always gone, but the thrill of the ups and downs kept her entertained for the entire time. "Did you win?" people ask. She always flashes her sly smile and says, "Sometimes!"