Ocean temperatures and their connections to weather trends have been making news. Five 91探花 experts offer their perspectives on the current El Ni帽o 鈥� a climate pattern in the tropical Pacific Ocean that affects weather worldwide. 91探花researchers comment on the current El Ni帽o, its effect on weather in the Pacific Northwest, as well as on regional and global ocean temperature trends.

, a 91探花research scientist at the , comments on the developing El Ni帽o:

“This El Ni帽o has evolved in a really interesting way. Since spring, the dynamical models have very confidently predicted an El Ni帽o event. But while the key region of the tropical Pacific has warmed quickly, the typical atmospheric response has lagged. The atmosphere in the tropical Pacific is only now becoming more typical of an El Ni帽o event, although it is still not fully matching the ocean surface. That鈥檚 unusual, because the tropical ocean and atmosphere tend to evolve together.

“It will be interesting to see how this El Ni帽o continues to evolve over the next few months, which will help determine the extent of impacts on our upcoming winter weather. Remote impacts in places like Seattle tend to be stronger for stronger El Ni帽o events. While sea surface temperature has typically been the main measure, the impacts might very well depend more on the atmospheric response. So the evolution of the system over the next few months will be key to the eventual local impacts in places like Seattle.”

Dennis Hartmann, professor of atmospheric sciences at the UW, on El Ni帽o and its effects:

“The impact of El Ni帽o on the Pacific Northwest varies a lot from one event to the other, depending on the spatial structure and size of the sea surface temperature changes in the tropics, and on the state of the atmosphere between the tropics and the Pacific Northwest. For that reason, the predictions of Pacific Northwest impacts based upon El Ni帽o events that happened in the past are quite uncertain.

“In addition, the climate has warmed significantly in both the tropics and outside the tropics since some of the prior big El Ni帽o events, in the 1970s and 1980s. That may add an additional complication to making an accurate forecast of how this winter will be different because of the current El Ni帽o event.”

Nick Bond, a research scientist at CICOES and Washington鈥檚 state climatologist, on El Ni帽o and its effects on Washington鈥檚 weather:

“El Ni帽o conditions are present now in the tropical Pacific Ocean, and they are very likely to persist through the coming winter. The effects on Washington鈥檚 weather are expected to feature relatively warm, and perhaps drier, weather than usual after Jan. 1, and ultimately a lower-than-normal snowpack in our mountains at the end of winter. El Ni帽o’s impacts on the weather in Washington state tend to be more consistent in the middle to latter part of the winter.

“But this is not written in stone 鈥� there has been variability among past El Ni帽os in terms of effects on Washington鈥檚 winter weather.”

Jan Newton, senior principal oceanographer at the 91探花Applied Physics Laboratory and director of the UW-based , on what oceanographers are seeing in regional waters:

“Conditions off Washington鈥檚 outer coast have varied and are mainly influenced by changes in coastal upwelling and downwelling in the Pacific Ocean. Temperatures off the outer coast are now 4 degrees Fahrenheit (about 2 degrees Celsius) above normal, though variable.

“In Puget Sound, we鈥檙e starting to see surface water temperatures shift from cooler than normal, or normal, to consistently warmer than normal, but only by less than one degree Fahrenheit (half a degree Celsius). Given the large-scale warmth in the satellite-measured sea surface temperatures offshore, I do expect that we will continue to see warmer-than-normal sea temperatures in Puget Sound.聽 However, it鈥檚 hard to predict if these differences from the average will stay small or will increase. What happens next will depend on ocean conditions and local weather.”

LuAnne Thompson, 91探花professor of oceanography, on the :

“The recent acceleration of ocean warming in the Atlantic is unprecedented in the historical record, and has created an Atlantic-wide marine heat wave. The ability of the ocean to absorb and store vast amounts of heat makes these types of events last longer. I study marine heat waves with a focus on their evolution in time and space. However, with more long-lasting, basin-wide events, such as the one we are seeing now in the Atlantic Ocean, we will need to reevaluate our approach.

“At a particular location, a marine heat wave occurs when the sea surface temperature is above a threshold, defined by what is typical for that time of year, and lasts for at least five days. However, with the global warming projected over coming decades, these dangerous hot water events will no longer be localized and of finite duration 鈥� they will no longer fit the traditional definition of marine heat waves. Instead, these marine heat wave events will become more persistent and widespread, and eventually will cover entire ocean basins.”

For more information, contact Levine at aflevine@uw.edu, Hartmann at dhartm@uw.edu, Bond at nab3met@uw.edu, Newton at janewton@uw.edu and Thompson at luanne@uw.edu.

Back then, climate science was not as politically charged as it is today.

Over 17 years, and since the 2008 launch of the UW’s College of the Environment, the program has evolved into a campuswide, interdisciplinary, student-driven program on climate change research, communication and action. A recent in Eos, published by the American Geophysical Union, looks back at the program’s unique history.

“A lot of schools have created a climate master’s degree. We’re really trying to give students who are getting disciplinary degrees the added benefit of the climate community and content,” said , who has administered the program since its launch. “It’s a very different program, so trying to explain it to people deserves more than two sentences.”

The program incorporates both traditional academic elements and more outwardly-focused, community-focused aspects.

Central to the program is a that allows 91探花students to add an interdisciplinary twist to their graduate education. Each student must take an introductory climate science course, that’s now available in three options for students with different levels of mathematical background.

The departments of atmospheric sciences, oceanography, Earth and space sciences, marine affairs and civil and environmental engineering are, of course, well represented. But the certificate program also attracts students in the Department of Philosophy, the Evans School of Public Policy, and even the Foster School of Business.

“This model works because climate is such an integrator across disciplines. And it’s becoming more and more so,” said former director , a professor of oceanography. “The PCC helps people get outside the disciplinary bubble, and that’s where a lot of the innovation is happening.”

Since the program began, each certificate student has done a climate-related outreach project. That effort is assessed and sometimes repeated to better reach a broader audience.

The projects run the gamut. A public policy graduate student studied the possibility of to the Puget Sound region, and presented her paper to city and county officials who plan utilities infrastructure. In 2016, a graduate student in marine affairs created outreach videos filmed in Alaska’s Prince William Sound. Other projects include meditation workshops focused on climate change, art projects, and presentations to union leaders on how climate change will affect working conditions in the future.

Many Program on Climate Change events bring people together. An annual , now in its third year, will take place April 27. Graduate students and postdoctoral researchers will give short, research-based talks to an audience that typically includes undergraduates, faculty members and friends.

The program also hosts more regular that are open to its members and the wider community. A recent gathering was a screening of a made by a retired oceanographer from the Applied Physics Laboratory. On Tuesday, April 16, the group will host a forum on to the public using social media.

Some graduate students have chosen outreach projects that contribute to the effort, creating curriculum for local high schools. A former graduate student made a recipe for creating an ice core that students could probe for chemical clues. Two current graduate students designed and taught a high school curriculum on geoengineering.

A current initiative by a 91探花faculty member and his graduate students is expanding a simple computer model developed to teach climate modeling in high schools. They will meet May 18 with middle- and high-school teachers to work on bringing the model to classes.

“It’s important that these workshops are two-way,” Bertram said. “The researchers are presenting their content, but they’re also learning from the teachers, who might say: ‘That’s not going to work in my classroom.'”

In 2011 the program launched an in climate that includes a seminar series focusing on a different climate-related topic each year 鈥� this winter looked at sea-level rise. While the seminar topic is intended to be of interest to the broader 91探花community and program members, those enrolled in the minor do writing assignments, including blog posts, a literature review and a one-page policy document.

Graduate students in the program organize an annual climate conference sponsored by the program and other 91探花departments and units, with increasing levels of funding from the National Science Foundation. That conference now alternates between the 91探花and the Massachusetts Institute of Technology, and is open to graduate students at both institutions. Last fall’s event, held at UW’s Center for Sustainable Forestry at Pack Forest, was the biggest yet.

“The students are more self-organizing than ever before,” said program director , a professor of atmospheric sciences. “I think their vision of what they can do in the world is much bigger.”

Even as the program takes stock and looks back at its history, organizers are continually experimenting. A recently developed “climate postdocs group” hosts weekly coffee meetings for 91探花postdoctoral students working on climate change.

“There are not many institutions that have a large enough community of climate-related faculty and students to convene something like this,” Thompson said. “The most important element, I think, is creating this intangible community around climate.”

Other co-authors of the recent Eos paper are founding director , a professor emeritus of oceanography, and former director , a professor of atmospheric sciences.

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For more information, contact Bertram at mab23@uw.edu or 206-543-6521 and Bitz at bitz@uw.edu.

Also unlike in that movie, and in theories of long-term climate change, these recent trends are not connected with the melting of the Arctic sea ice and buildup of freshwater near the North Pole. Instead, they seem to be connected to shifts at the southern end of the planet, according to a recent 91探花 in the journal Geophysical Research Letters.

“It doesn’t work like in the movie, of course,” said , an oceanographer at the UW’s Applied Physics Laboratory. “The slowdown is actually happening very gradually, but it seems to be happening like predicted: It does seem to be spinning down.”

The study looked at data from satellites and off Miami that have tracked what’s known as the Atlantic overturning circulation for more than a decade. Together they show a definite slowdown since 2004, confirming a trend suspected before then from spottier data.

Looking at other observations to determine the cause, the researchers ruled out what had been the prime suspect until now: that massive melting and freshening in the North Atlantic could stop water from sinking and put the brakes on the overturning circulation, which moves warmer water north along the ocean’s surface and sends cold water southward at depths.

“It appears that this 10-year slowdown is not related to salinity,” Kelly said. In fact, despite more ice melt, surface water in the Arctic is getting saltier and therefore denser, she said, because of less precipitation. “That means the slowdown could not possibly be due to salinity 鈥� it’s just backwards. The North Atlantic has actually been getting saltier.”

Instead, the authors saw a surprising connection with a current around the southern tip of South Africa. In what’s known as the , warm Indian Ocean water flows south along the African coast and around the continent’s tip toward the Atlantic, but then makes a sharp turn back to join the stormy southern circumpolar current. Warm water that escapes into the Atlantic around the cape of South Africa is known as the Agulhas Leakage. The new research shows the amount of leakage changes with the quantity of heat transported northward by the overturning circulation.

“We’ve found that the two are connected, but I don’t think we’ve found that one causes the other,” Kelly said. “It’s more likely that whatever changed the Agulhas changed the whole system.”

She believes atmospheric changes may be affecting both currents simultaneously.

“Most people have thought this current should be driven by a salinity change, but maybe it’s the [Southern Ocean] winds,” Kelly said.

The finding could have implications for northern European and eastern U.S. climates, and for understanding how the world’s oceans carry heat from the tropics toward the poles.

“I think it changes how we think about the whole Atlantic overturning circulation, of which the Gulf Stream is a part,” said co-author , a 91探花professor of oceanography. “It brings back the role of the atmosphere into what’s controlling the climate in the high latitudes, that it’s not all driven by what’s happening in the oceans.”

And while a slowdown of the Gulf Stream and broader overturning circulation, for whatever reason, would bring less warm water to eastern North America and Western Europe, any effects are overwhelmed by the overall warming due to global climate change.

“So that whole concept in the movie of New York harbor freezing doesn’t make any sense,” Kelly said. “If the Gulf Stream doesn’t carry as much heat from the tropics, it just means that the North Atlantic is not going to warm up as fast as the rest of the ocean 鈥� it’s not going to cool down.”

The study was funded by NASA and the U.K.’s Natural Environment Research Council. Other co-authors are at the 91探花Applied Physics Laboratory, Dewi Le Bars at the Royal Netherlands Meteorological Institute and Elaine McDonagh at the U.K.’s University of Southampton.

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For more information, contact Kelly at kellyapl@uw.edu or 206-543-9810 and Thompson at luanne@uw.edu or 206-543-9965.

NASA: NNX13AH19G, NERC: NE/G007764/1

The Paris talks were attended by thousands of delegates, including from the 91探花. At the time, 91探花researchers in Seattle the expansion of discussions to include public policy and human health, and emphasized the need for a timely, durable international agreement.

Now, a few 91探花faculty members comment on the signing as countries move toward implementing its contents.

, a 91探花professor of atmospheric sciences, calls the signing an “encouraging” step forward. But he notes that the United Nations Framework Convention on Climate Change was adopted in 1992, and the was signed in 1997, but never ratified by the U.S.

Since then, he said, the world has emitted more carbon dioxide than even the highest expert predictions at that time. The ‘s commitments are voluntary, he noted, with no mechanisms for enforcement, and its goals are modest.

“Much more aggressive steps are necessary to keep global warming in check, and time is running out,” Hartmann said. “The 2013 Intergovernmental Panel on Climate Change report [on which he was a ] showed that we are about halfway to the amount of greenhouse gas emissions that will produce 2 degrees Celsius of warming, and at present rates of release we will get there in about 25 years. We need to stop the increase in carbon dioxide to avert 2 C of warming, and the promises under the Paris Agreement will not achieve that. We need nations to do much more.”

, 91探花professor of oceanography and director of the 91探花, said the agreement “represents an important step for the international community in its effort to ‘limit dangerous inference of the climate’ as set out [in 1992] by the UN Framework Convention on Climate Change.”

She noted that each country sets its own voluntary . “Because of this bottom-up approach, the country pledges are more aspirational than was found in Kyoto, potentially resulting in much larger emission reductions than many thought possible.”

She added: “While some have said that the bold goal set in Paris of keeping warming below 2 C is unrealistic, the Paris Agreement gives confidence that the international community can work together to solve this defining challenge of this century. I am hoping for swift ratification of this agreement, and that countries with both large and small emissions pledge significant reductions in emissions.”

, a 91探花professor of political science and director of the 91探花, said “the Paris Agreement is a good step forward because China and India, along with industrialized countries, are on board.”

But he noted the pledges are voluntary. “Kyoto and other international agreements show that international agreements with mandatory targets face huge problems in domestic translation and implementation.”

He echoed others on the voluntary targets, and the lack of incentives to meet them. “This holds not only for China and India, but also for the U.S., where the Congress remains opposed to climate-change mitigation.” Prakash said he would like to see country-specific plans and budgets “before speculating on the possibility of the success of the Paris agreement.”

, a lecturer in the 91探花Jackson School of International Studies who writes on international relations and geopolitics, said “overall, it represents an essential step, a major move forward.”

But he wondered about the agreement’s focus on renewables 鈥� mainly solar and wind 鈥� rather than other options such as hydropower, fossil fuels with capture of carbon emissions, and especially nuclear power.

“We have seen, in the 1970s and 80s, what harm can be done by exaggerated claims about what renewable technologies can actually deliver,” Montgomery said. “Reducing carbon emissions significantly will require every means at our disposal.”

, a 91探花professor of marine and environmental affairs, called it “mission impossible.” She said: “We have a global-emissions goal we are not sure is correct, national goals that are in no way connected to it, and we really will [have no way to] know if we met it or not.”

She described the agreement’s more than per year to help developing countries enact new technology and mitigate and adapt to a changing climate as inadequate.

, a 91探花professor of chemical engineering and director of the 91探花, said that “the Paris Climate Agreement 鈥� combined with the [governmental] and [private] pledges to invest billions of new dollars in clean energy 鈥� is a signal that the world is committed to accelerating the development of scalable clean energy innovations.”

He noted that Washington state has already invested in the Clean Energy Institute and other efforts that join university researchers and national labs to develop new materials for renewable energy and integrate them into the electrical grid.

“What we need now is an ecosystem that has more fundamental scientific discoveries happening within earshot of the entrepreneurs and investors who share this same sense of urgency to mobilize against an environmental challenge that many of the world’s most powerful nations now recognize as a great threat to humanity.”

, a 91探花undergraduate in environmental sciences, forestry and economics who attended the summit as part of the International Forestry Students’ Association, said “to me, the signing of the Paris climate agreement is a signal 鈥� the sound of a call from the global world to this generation’s young professionals and students.

“It is telling us that we need to begin crafting creative solutions to accomplish these ambitious goals 鈥� this need stretches from finance to agriculture, international trade to urban design.”

Abraham recalls meeting people from around the world during her time in Paris.

“We all have a part to play, and the agreement is the reminder that we are not alone. In each country, each city, there will be hordes of people working to meet the goals of the agreement 鈥� and it is this new truth that I believe will make all the difference.”

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