JPL BLOGS
Inside Views on Outer Space
Hear from scientists, engineers and other experts as they offer a fascinating look at JPL missions, science and history.
Earth Right Now | June 15, 2015
Because There Are No Spare Earths
“Do we think about the aerosol propellant in our underarm deodorant every day?” Gavin Schmidt, climatologist and director of The Goddard Institute for Space Studies (GISS), asked me. “I don’t think we even have aerosols anymore,” I answered, wondering where he was going with this.
“That’s the point,” he continued, “and nobody cares. Nobody cares where your energy comes from; nobody cares whether your car is electric or petrol. People confuse energy supply with where the energy is supplied from.” He was trying to make the point that as long as people have the things they want, it doesn’t matter, to the vast majority of us, how we get them. This means that as long as the light switch still turns on the lights, most people would barely notice if we were to shift from burning fossil fuels to energy sources with less impact on Earth’s climate (just as people don’t notice that ozone-depleting propellants aren’t used in aerosol cans any more).
I was eager to speak with Dr. Schmidt because of his passion for communicating climate science to public audiences on top of his work as a climatologist. Schmidt is a co-founder and active blogger at Real Climate and was also awarded the inaugural Climate Communications Prize, by the American Geophysical Union (AGU) in 2011. “My goal in communicating,” he explained, “is a totally futile effort to raise the level of the conversation so that we actually discuss the things that matter.”
Since the mere mention of a computer model can cause an otherwise normal person’s face to glaze over, I thought Schmidt, a leader in climate simulations and Earth system modeling, would be the ideal candidate to explain one of the most important, yet probably one of the most misunderstood, instruments scientists have for studying Earth’s climate. See, people commonly confuse climate and weather, and this confusion is perhaps most pronounced when it comes to understanding the difference between a weather forecast and a climate simulation.
Numerical laboratory
Schmidt’s work routine is much like that of any other scientist. He spends a few months preparing experiments, then a few more months conducting the experiments, then a few more months refining and improving the experiments, then a few more months going back and looking at fine details, then a few more months … you get the idea. Climate scientists use complex computer simulations as numerical laboratories to conduct experiments because we don’t have a bunch of spare Earths just lying around. These simulations model Earth’s conditions as precisely as possible. “A single run can take three months on up on super computers,” Schmidt said. “For really long runs, it can take a year.” NASA scientists can reserve time for High-End Computing Capability at the NASA Advanced Supercomputing facility and/or the NASA Center for Climate Simulation to run simulations. Like an astronomer who reserves time on a large telescope to run her experiments, Schmidt books time on these computers to run his.
Schmidt asks the computer to calculate the weather in 20-minute time steps and see how it changes. Every 20 minutes it updates its calculation over hundred-year or even thousand-year periods in the past or the future. “The models that we run process about three to four years of simulation, going through every 20 minute time step, every real day.”
A typical climate simulation code is large, as in 700,000 lines of computer code large. For comparison, the Curiosity Rover required about 500,000 lines of code to autonomously descend safely on Mars, a planet 140 million miles away with a signal time delay of about 14 minutes. The size of a typical app, such as our Earth Now mobile app, is just over 6,000 lines of code. Climate simulations require such a large quantity of code because Earth’s climate is so extraordinarily complex. And, according to Schmidt, “Complexity is quite complex.”
Like a scientist who runs an experiment in a science lab, climate modelers want code that’s consistent from one experiment to another. So they spend most of their time developing that code, looking at code, improving code and fixing bugs.
The model output is compared to data and observations from the real world to build in credibility. “We rate the predictions on whether or not they’re skillful; on whether we can demonstrate they are robust.” When models are tested against the real world, we get a measure of how skillful the model is at reproducing things that have already happened. Then we can be more confident about the accuracy in predicting what’s going to happen.
Schmidt wants to find out where the models have skill and where they provide useful information. For example, they’re not very useful for tornado statistics, but they're extremely useful on global mean temperature. According to Schmidt, the credible and consistently reliable predictions include ones that involve adding carbon dioxide to the atmosphere. “You consistently get increases in temperature and those increases are almost always greater over land than they are in the ocean. They’re always larger in the Arctic than in the mid-latitudes and always more in the northern hemisphere than the southern, particularly Antarctica. Those are very, very robust results.”
Lately, his team has been working on improving the code for sea ice dynamics to include the effects of brine pockets (very salty fluid within the ice matrix) as well as the wind moving the ice around. For example, to understand the timeline for Arctic sea ice loss, his team has to work on the different bits of code for the wind, the temperature, the ocean and the water vapor and include the way all these pieces intersect in the real world. After you improve the code, you can see the impact of those improvements.
I asked Schmidt what people’s behavior would look like “if they understood that burning fossil fuels produces carbon dioxide, which causes global warming.” He replied, “People would start focusing on policies and processes that would reduce the amount of fossil fuels without ruining the economy or wrecking society.” Then he added, “I think, I hope! that people will get it before it’s too late.”
I hope so, too.
› Visit Earth Right Now to comment on this post
TAGS: EARTH, CLIMATE, CLIMATE MODELS
Earth Right Now | June 8, 2015
Jason-3 and the Argonauts
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:
http://sealevel.jpl.nasa.gov/
http://sealevel.jpl.nasa.gov/missions/jason3/
I look forward to your comments.
- Laura
› Visit Earth Right Now to comment on this post
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.
TAGS: EARTH, OCEANS, JASON-3, SATELLITES, CLIMATE CHANGE
Earth Right Now | May 12, 2015
The Sun is Always Shining on Joan Feynman
“I knew the names of the planets in order before I went to kindergarten," Joan Feynman, the younger sister of the famous physicist, told me. "My father was delighted by science. My brother, of course, was Richard Feynman—gifted as hell. When I was about three or four, he taught me to add numbers. I’d add them and if I got them right, he’d give me a reward. The reward was allowing me to pull his hair. As soon as I pulled his hair he’d make a terrible face.”
Joan Feynman (left) and her brother Richard (right). Richard Feynman image courtesy of the National Nanotechnology Initiative.
Joan and I were supposed to be discussing her work on sunspots, aurora, geomagnetism and solar winds but we kept veering off on tangents, and I’m certain it was all my fault. I was charmed by her Long Island accent and wacky sense of humor, and the fact that at 88, she holds a research position at NASA’s Jet Propulsion Laboratory.
But Joan is much more than a little sister and a funny storyteller: She’s a legit solar physicist who spent a long career analyzing the patterns of sunspot frequencies and their relationship to aurora. You see, people who live meaningful lives look deeply at the world around them—deeply enough to be moved, and sometimes deeply enough to move others. So in one afternoon, she managed to transfer a bit of her passion to me. I became mesmerized, mind-blown and in awe of solar physics.
“People have been observing aurora and drawing pictures of them for thousands of years,” she explained. “We have records of them from the year 450 C.E. to 1450 C.E. The Swedes and Norwegians had made lists of what days there were aurora and the Chinese made lists. So they knew that when there was a big aurora in China, there was a big aurora in Sweden.”
An aurora shines over Whitehorse, Yukon. Image courtesy of David Cartier, Sr.
Obviously I know that counting sunspot and aurora frequencies sounds completely dorky. But trust me, it feels like diving into a whole other reality when you spend time talking with Joan.
She went on to describe how “aurora, the geomagnetic currents and solar flares are part of the same process. Solar flares put out huge disturbances in the magnetic field of the solar wind and in the kind of particles that come out, and they cause the aurora.” Solar geomagnetic activity varies over 11-year and 88-year cycles. The 88-year Gleissberg cycle, a variation in amplitude of the 11-year solar cycle, is what’s captivated Joan throughout her career. “The whole point of science is to understand the mysteries you see around you,” she said. And solar activity has been part of that mystery for Joan her entire life.
Check out this story about the first time she saw an aurora as a very young child:
“One night I had already gone to bed. I was supposed to stay in bed, but my brother got permission to come in and wake me up because there was an aurora in the sky over the golf course near our home in Long Island. It looked to me like marvelous lights in the sky moving back and forth. It was very impressive to me. My brother said to me that nobody knows what that’s from, which was true in 1930.”
“I was fascinated by that aurora,” she continued. “They’re gigantic, they’re impressive; everybody runs out to see them. They were mysteries. The sky is lit up red and gold and yellow and shooting.”
When I told her that I didn’t even know they had aurora in Long Island, she said, “Auroras come down to lower latitudes when they’re very big.”
Are you starting to see how I got all jacked up just listening to her? I’ve never even seen a real live aurora. It was like sitting next to a kid with a better toy. She was taunting me, describing colors, movement and wild sky. I was hooked and jealous.
I want to see one now!
Although today we understand that aurora are caused by the interaction between the Earth’s magnetosphere and the magnetic particles in the solar wind, there are still plenty of solar mysteries to keep Joan occupied. “How does the sun do that?” She wants to know. “How does the sun manage to get a cycle of 88 years?”
For me, the question is clear: “If there were lots of them in the 1930s, and there’s an 88-year cycle, does that mean I’m going to get to see them soon?”
She answered: “It’s time for me to write the next paper on this: Are they back?”
I look forward to your comments.
- Laura
› Visit Earth Right Now to comment on this post
TAGS: AURORA, EARTH, JOAN FEYNMAN, SUN, SOLAR FLARES
Earth Right Now | May 4, 2015
Rainbow of Hope
When you read my blog, you’re either going to say “no way” or “finally.” And honestly, I’m kind of saying both, but definitely leaning more toward the latter.
See, normally I’m weighed down by the epic crisis known as global climate change (ugh). But this morning, I’m thinking: "finally." At last, Earth’s climate is going to get the attention it deserves. Finally, enough people are showing they care and it’s going to make a difference. Finally.
True, it’s hard to believe—even for me. But deep in my bones, I feel the tide starting to turn. (And by using that expression, I do not mean higher tides are flooding low-lying regions. That’s been going on for a while.)
What I mean is that everywhere I turn I see people paying attention to Earth’s climate. Not enough attention yet, mind you, but at least people are talking about it. And for the first time in a long time, I feel hopeful.
Maybe this optimism has something to do with the rainbow I saw while walking out in the rain over the weekend. Maybe it’s because NASA’s Global Climate Change website won both the People’s Voice and the juried Webby Awards for Best Green Site, and our Earth Now mobile app won in the Education and Reference category.
Whatever it is, I hope you’ll join me in my moment of optimism, because together—you and me—we are responsible for making this planet the kind of world we want to live in.
Bring it.
- Laura
› Visit Earth Right Now to comment on this post
TAGS: EARTH, CLIMATE CHANGE, RAINBOW
Earth Right Now | April 21, 2015
Give Peas a Chance
"Excuse me. What kind of plants are those?"
I was squatting down in my front yard as I do every morning, picking veggies for breakfast, when I heard a voice behind me. I stood up and turned around. It was a neighbor from across the street and three houses down. "They're peas," I told him.
A few years back, we were among the first in our neighborhood to rip out the grass in our parkway so we could plant drought-tolerant succulents and other cool-looking plants instead of boring, old, water-sucking grass. Little did I know that, along with saving money and water, the process also attracted the curiosity of lots of people on our street. We were bucking the trend, breaking the norm, doing something different. And people wanted to hear all about our new way-cooler-looking-than-grass plants.
Then we created a vegetable garden in the front yard. The goal was to have a cool modern-looking yard and have some fun growing and eating good food. We succeeded in harvesting enough kale, tomatoes, artichokes, chard and peas to feast on for many weeks (and I was able to include my own home-grown items in the yummy edible NASA satellite models I made).
But our gardening exploits brought us another unexpected advantage. We were already growing food in our backyard and side yard, but we learned that when you plant cool stuff in the front yard, lots of passersby stop to check it out. It's usually the artichokes that evoke the most frequent comments and questions. I mean, artichokes are weird-looking. (Shhh, don't you dare tell them I said that!) But over the years our vegetable garden has become a magnet that's attracted friendship and community in our neighborhood. And we've seen many other lawns turn into gardens, too.
There's no way to tell what will unfold when you start to do something, even the smallest thing. Actions grow and expand, sort of like the way our peas started out small, crawled past their trellises and are now getting tangled up into each other. What you create in the world can take on a life of its own, beyond what you might ever imagine.
Every Earth Day I write about taking an individual action, and every time I write this I get all kinds of criticism about how doing one small thing isn't enough.
But next time you start to think that your actions are too small to make a difference, think about me and my silly old peas. Remember that I reached down, picked a fresh pea and handed it across the stucco wall to the guy who lives down the street-the guy whom I hadn't yet connected with in all these years; one of the last of my neighbors to reach out. He told me that he and his wife saw our yard and decided to plant a garden as well.
And while you're at it, remember to celebrate Earth Day this year by joining NASA as we all share views of our favorite place on Earth on social media. We hope that if all of us take a moment to acknowledge and remember our planet, we'll feel more connected to it.
You can post photos, Vines and/or Instagram videos. Just be sure to include the hashtag #NoPlaceLikeHome - no matter what social media platform you're using.
You can also get on board now by using our #NoPlaceLikeHome emoji as your profile pic. Join the Facebook or Google+ events and invite your friends to participate. Pledge to spend one day celebrating the planet that over 7 billion people call home.
Find out more at http://www.nasa.gov/likehome/.
Thanks for everything you do to care for our planet.
I look forward to your comments.
- Laura
› Visit Earth Right Now to comment on this post
TAGS: EARTH, EARTH DAY, SUCCULENTS, CALIFORNIA DROUGHT, CLIMATE, GREEN
Earth Right Now | April 9, 2015
Earth Day: All the Drops Add Up
A couple of weeks ago, I received an email from a high school student in Michigan. She was working on a climate change research project and wanted to ask me a few questions, so of course I said yes. She asked me about my job at NASA, what I thought were the most pressing aspects of Earth’s changing climate, and the ocean’s role in long-term climate trends.
But then there was this question: “I like to do everything I can each day to reduce my own contribution to climate change … I want to encourage my peers to take small actions each day to help our climate, but will it really matter beyond making people feel good about themselves? ... It seems like there is nothing individuals can do.”
Now I’m a pretty direct person, but I’m also fairly kind to high school students, especially those I’ve never even met. Yet this time, I let her have it:
“You are wrong,” I stated bluntly, wishing an error buzzer noise could accompany my outgoing email message. “You are wrong about your own contribution being insignificant. One person's efforts are hugely important and don't you ever forget it.”
Sure, I understand it’s easy to feel completely overwhelmed and powerless in the face of a tremendous problem such as climate change. I work on a climate change website every day—I get it. Just thinking about climate change and other environmental issues gets depressing. These problems are too big; they feel insurmountable. And then when you want to do something, it seems like whatever you do is too small, like a tiny drop in a gigantic pit.
But each and every single individual action, no matter how small it may seem, adds to what ultimately makes a difference. You may think, “One person isn’t going to make a big difference; it’s not going to be a big deal.” But taking responsibility for how your life affects the environment is a huge deal.
The Earth is amazing. And when you look at the view from space you see that the whole Earth is your home, our home. You see that what happens on the other side of the planet matters.
So go ahead: Take the journey from “there’s not much I can do” to “there are many things I will commit to doing.” Because together, our individual actions can make a bigger impact than you might ever imagine. And since Earth Day is coming up on April 22, now is the perfect time to begin that journey.
One of the things we’re doing to celebrate Earth Day this year is asking people around the world to share on social media views of their favorite place on Earth. As we rush through our busy lives, sometimes we forget to appreciate how much we care about this place we call home. We hope that if all of us take a moment to acknowledge and remember our planet, we'll feel more connected with it. And that's one small step toward making it a better place.
You can post photos, Vines and/or Instagram videos. Just be sure to include the hashtag #NoPlaceLikeHome – no matter what social media platform you’re using.
You can also get on board now by using our #NoPlaceLikeHome emoji as your profile pic. Join the Facebook or Google+ events and invite your friends to participate. Pledge to spend one day celebrating the planet that over 7 billion people call home.
Find out more at http://www.nasa.gov/likehome/.
Thanks for everything you do to care for our planet.
- Laura
› Visit Earth Right Now to comment on this post
TAGS: EARTH, EARTH DAY, CLIMATE CHANGE, ENVIRONMENT
Earth Right Now | March 19, 2015
Time to Take the Giant Space Antenna for a Spin!
This Thursday, March 19, NASA's latest mission will begin preparation for its next great milestone: making the wicked-amazing antenna rotate.
A number of spacecraft have rotating parts, such as the RapidScat mission and the Global Precipitation Measurement (GPM) mission, but those don't hold a candle to the dynamics of Soil Moisture Active Passive (SMAP).
SMAP's antenna is 20 feet in diameter. The larger the antenna, the more complex its behavior can be, which makes it more difficult to control. Just imagine swinging a 20-foot baseball bat over your head. Yikes!
Right now the antenna is locked in position until the mission "ops" (operations) team completes its checks of the entire instrument's function and confirms operability. They have taken measurements with the radar and the radiometer. They know the instruments are working by comparing the measurements to how they were tested on the ground before launch. The signals look appropriate; they're seeing what's expected. But the antenna's fixed position means it's measuring only a small strip of the ground below.
Once the antenna starts to spin, we'll be able to measure a much larger area and monitor soil moisture around the entire Earth every two to three days.
These are the three steps to achieving "spin up":
1. Engineers unlock the antenna.
2. A few days later, they spin the antenna slowly.
3. They gradually spin it faster.
At each step, they'll verify how it's performing. The engineers will then conduct a more comprehensive checkout of the instrument's systems. With the antenna spinning, they'll get to see the instrument's full performance for the first time.
After the spinning checkouts are completed ... Voilà! Bibbidi bobbidi boo! SMAP will start mapping global soil moisture and return data!
I look forward to your comments.
- Laura
› Visit the Earth Right Now page to join the conversation
TAGS: EARTH, SMAP, SOIL MOISTURE, SPACECRAFT, CLIMATE,
Earth Right Now | March 4, 2015
Four Amazingly Useful Life Lessons from a NASA Flight Software Engineer
Unless you call yourself a rocket scientist, you probably don’t think your daily routine has much in common with flight software engineering. But you would be wrong.
Flight software engineers write computer code for NASA spacecraft, which is complicated because—hello—flying spacecraft into space is complicated.
Flight software runs the instruments and sensors that operate thermal control, spin stabilization on all three axes, uplink and downlink to communicate with spacecraft, data collection and handling, a cruise phase, a descent phase and sometimes a “landing on the surface of a planet” phase. And some of this happens simultaneously. (And I thought feeding the cat and dog at the same time was rough.)
If the spacecraft is far away, like, dude, on Mars or beyond, there’s no controlling it from the ground with a joystick, so the software has to be written to allow the spacecraft to run autonomously.
But the experiences of a flight-software-engineering person* are actually the same as the experiences of a regular-person person, from planning a family reunion, to cleaning the garage, to simply shopping for tonight’s dinner. If you skip the bits about the flying, disregard the software and pay no attention to the engineering, then what you’re left with is some amazingly useful life lessons:
JPL | December 8, 2014
Forests and Climate Change
Riley Duren, chief systems engineer for the Earth Science and Technology Directorate at NASA's Jet Propulsion Laboratory, is reporting from the 2014 United Nations Climate Conference in Lima, Peru.
I mentioned previously that Peru is home to some of the most important forests in the world in terms of their vulnerability to future impacts from climate change and development pressure as well as their potential to mitigate climate change. This underscores the importance of certain elements of the UN Framework Convention on Climate Change. In particular, the Reduction of Emissions from Deforestation and forest Degradation (REDD+) program seeks to address the second-largest human contribution to climate change after fossil fuel use (see Friday's post).
Detailed definitions vary, but deforestation generally refers to conversion of forested lands to some other use -- particularly large-scale agriculture but also mining and expansion of infrastructure and cities. Degradation is distinct and refers to a diminished capacity of forests to store carbon, support ecosystems and other services. Forest degradation is caused by human activity such as commercial logging, fuel wood collection, charcoal production, and livestock grazing as well as natural forces like storms, insect damage and wildfires.
Forests play a critical role in Earth's carbon budget because healthy, growing trees and other forest elements remove and store carbon from the atmosphere -- converting it to "biomass" in trees, shrubs and soil. This makes forests one of the most effective countermeasures for fossil fuel CO2 emissions (see graph, below).
The Earth's evolving carbon budget from the start of the Industrial Revolution through present day. Carbon dioxide (CO2) flux is shown in units of Giga (billion) tons of carbon per year (GtC/year). Fluxes of carbon emitted to the atmosphere are indicated by "+". Fluxes of carbon removed from the atmosphere are indicated by "-". The plot shows the dramatic growth in fossil fuel CO2 emissions since the mid-20th century and slight decline in emissions from deforestation and other land use change. The graph also shows the corresponding growth in the three major carbon sinks: the atmosphere, land (forests) and oceans. The variability or "jumpiness" in the land sink from year to year is likely due to changes in precipitation associated with climate variability like El Nino. The future ability of the land and oceans to remove CO2 from the atmosphere remains an area of great uncertainty. Image source: Global Carbon Project
However, when forests are degraded or destroyed, the storage potential of the forest is reduced or eliminated. Additionally, if the downed trees are burned and/or decay and forest soils are disturbed, they release their stored carbon (sometimes centuries worth) into the atmosphere. So there's an incentive to both keep forests growing to store carbon and to avoid disturbing the carbon already stored in them.
Programs like REDD+ are intended to incentivize governments and landowners to preserve and restore their forests. For example, in carbon-trading programs, governments and business can "offset" their fossil fuel CO2 emissions by purchasing credits from forest owners who can prove they're storing an equivalent amount of emissions by implementing certain protocols, including independent measurement and verification. These efforts are particularly important in the tropics, which are home to most of the world's forest carbon, as well as the countries experiencing the most rapid growth and development pressures, very similar to the period of growth the US underwent in the 1800s.
Over the weekend, I attended the Global Landscape Forum to interact with policy makers, conservation groups and scientists on the subject of forest carbon monitoring. One of the panel sessions featured JPL's Dr. Sassan Saatchi and other experts who described the current capabilities and limitations of remote-sensing tools to assess the status and health of forests, including their carbon stocks and "fluxes" (removals from and emissions to the atmosphere).
The remote-sensing methods discussed included imaging systems like the US Landsat satellites that are being used to track forest-cover change as well as future systems that will improve understanding of forest degradation such as NASA's ICESAT-2 mission, the NASA-India Synthetic Aperture Radar (NI-SAR) and the European Space Agency's BIOMASS mission. The role of flying radar and lidar (laser radar) instruments on aircraft over high priority areas was also discussed.
Of course decisions about forest management involve dimensions other than climate change mitigation -- typically involving a balance between economic growth and the value of existing ecosystem services offered by forests. Biodiversity in particular is gaining prominence in decision-making given the societal and economic value it represents. Biodiversity, which refers to the number of species in a given area, is often highest in forest ecosystems (particularly in the tropics) given they provide a combination of food, shelter and water resources. The information required to evaluate biodiversity is related to, but distinct from, the data used to assess forest carbon. (I'll try to describe the role of remote-sensing in assessing biodiversity in a future post.)
Meanwhile, closing with some personal experience, I'm posting a couple of photos I took while working on my own forest conservation and biodiversity project in Hawaii.
A cloud forest on the flank of Hualalai volcano on the Big Island of Hawaii. The giant, ancient trees and native understory plants thrive in the high-altitude, moist environment provided by the persistent presence of clouds -- providing carbon storage as well as a habitat for threatened plant and bird species. The benefits of the unique Kona weather pattern are offset by the introduction of invasive weeds and destructive feral animals like pigs and sheep.Image credit: Riley Duren
A threatened I'iwi honeycreeper, endemic to the Hawaiian Islands, sips nectar from an Ohia tree blossom. Historically, this species ranged across the Hawaiian Islands but today only survive in a few high-elevation forests given the combined pressure of deforestation and avian malaria at lower elevations from non-native mosquitoes. The I'iwi, like many other Hawaiian bird and plant species, lacks the natural defenses to withstand the combined pressure from development and climate change. Management efforts focus on conserving, restoring and building resiliency in threatened forest habitats. Image credit: Riley Duren
TAGS: EARTH, FORESTS, CLIMATE CHANGE, CARBON
JPL | December 5, 2014
Carbon and the City
Riley Duren, chief systems engineer for the Earth Science and Technology Directorate at NASA's Jet Propulsion Laboratory, is reporting from the 2014 United Nations Climate Conference in Lima, Peru.
We arrived in Lima, Peru, late last night and made our way to the United Nations climate conference venue this morning -- an impressive complex known locally as the Pentagonito or “Little Pentagon.” As host country and city, Peru and Lima are representative of several key fronts in the international effort to confront climate change. Peru is home to some of the most significant tropical forests on Earth that are the focus of programs to preserve their vital role in storing carbon and critically endangered ecosystems (more about that tomorrow). With a population approaching 10 million people, Lima itself is a rapidly growing megacity -- one of many in the developing world.
The latter topic is the focus of this post and the event I’m participating in later today at the US Center: “Understanding the Carbon Emissions of Cities.” I’ll be joining colleagues from the US National Institute of Standards and Technology, Arizona State University, Laboratoire Des Sciences du Climat et de l'Environnement (France), and Universidade de São Paulo (Brazil) in presenting the motivation for and recent scientific advances in monitoring urban carbon pollution. There won’t be a live stream but the event will be recorded - keep an eye on the US State Department’s YouTube page where it should be posted this weekend.
So what is “carbon pollution” and why should we care about it? Most of us are familiar with the general topic of air pollution; just ask anybody who has asthma or knows a friend or family member with respiratory problems. Cities are notorious sources of air pollutants or smog -- including visible particles (aerosols) and invisible but caustic ozone. One can find many examples of success stories where air quality has improved in response to clean-air standards as well as horror stories in cities lacking such standards. However, this familiar topic of air quality is mostly limited to short-lived pollutants -- compounds that only persist in the atmosphere for hours or days. Those pollutants are important because of human health impacts but they’re not primary drivers of climate change. Carbon dioxide (CO2) and methane (another carbon-based molecule) on the other hand, are long-lived gases that trap heat in the atmosphere for many years. Once CO2 and methane are in the atmosphere, they remain there for a long time -- centuries, in the case of CO2. Most people are unaware of the presence of CO2 and methane because they’re invisible and odorless and don’t have an immediate impact on health, but those gases are THE big drivers of climate change.
There are many sources of CO2 on Earth, including natural emissions that, prior to the industrial revolution, were balanced by removals from natural carbon scrubbers like forests and oceans. However human activity is rapidly changing the balance of CO2 in the atmosphere, leading to an unprecedented growth rate. Most of these human CO2 emissions come from burning fossil fuels like coal and oil. These fossil emissions are responsible for about 85 percent of humanity’s CO2 footprint today and, globally, they’re continuing to accelerate. So any successful effort to avoid dangerous climate change must have fossil CO2 mitigation at its core. Managing methane is also important given its greater heat trapping potential than CO2.
Why focus on carbon from cities? It turns out that urbanization – the increasing migration of people from rural areas to urban centers – has concentrated over half the world’s population, over 70 percent of fossil CO2 emissions and a significant amount of methane emissions into less than 3 percent of the Earth’s land area! So cities and their power plants represent the largest cause of human carbon emissions. In 2010, the 50 largest cities alone were collectively the third largest fossil CO2 emitter after China and the US – and there are thousands of cities. At the same time, in many cases, emissions from cities are undergoing rapid growth because of urbanization.
But there’s also a silver lining here.
Many cities are beginning to serve as “first responders” to climate change. While national governments continue to negotiate over country-level commitments, mayors of some of the largest cities are already taking action to reduce their cities’ carbon footprints, and they’re working together through voluntary agreements. Additionally, the concentrated nature of urban carbon emissions makes measuring those emissions easier than measuring entire countries.
Measuring the carbon emissions of cities is important (you can’t manage what you can’t measure) and challenging given the number of sources and key sectors and uncertainty about how much each contributes to the total carbon footprint. For example, in a typical city, CO2 is emitted from the transportation sector (cars, trucks, airports, seaports), energy sector (power plants), commercial and industrial sectors (businesses, factories) and residential sector (heating and cooking in homes). Likewise, urban methane sources include landfills, wastewater treatment plants, and leaks in natural gas pipelines. Mayors, regional councils, businesses and citizens have a number of options to reduce their carbon emissions. Measuring the effect of those efforts and understanding where and why they’re not having the intended impact can prove critical to successful mitigation. It also has economic implications -- toward identifying the most cost-effective actions and supporting emissions trading (carbon markets) between cities and other sub-national entities.
How can we measure the carbon emissions of cities? That’s the focus of the Megacities Carbon Project and the topic of our event in Lima today. Briefly, this involves combining data from satellites and surface-monitoring stations that track concentrations of CO2, methane and other gases in the atmosphere over and around cities with other, local data sets that contain information about key sectors. Pilot efforts in Los Angeles, Paris, Sao Paulo and other cities are beginning to demonstrate the utility of these methodologies. Satellites like NASA’s Orbiting Carbon Observatory-2 and other future missions, when combined with a global network of urban carbon monitoring stations, could ultimately play an important role in enabling more effective mitigation action by the world’s largest carbon emitters: cities.
TAGS: CARBON, EARTH, CLIMATE, MEGACITIES