August 14th: 91 volcanoes discovered under the West Antarctic Ice Sheet!!!! This is so exciting on multiple levels, from the pure geo-nerdery to the potential climate change impacts. Geeking out. (Read Andrew Freedman’s article for all of the details, but its possible that (1) geothermal heating associated with the volcanoes will contribute to melting and destablization; (2) melting the ice sheet could enhance volcanic activity as the pressure is released; and (3) the volcanoes will help anchor the ice sheet in place and reduce the possibility of catastrophic collapse. These are not mutually exclusive possibilities.)
August 10th: A new paper in Science shows that European floods have shifted in timing, up to 2 weeks earlier per year, since 1950. What’s particularly intriguing about the study is that the timing shifts haven’t just occurred in snowy regions, but also in places where rainfall is causing water tables to rise and soils to become more saturated earlier in the spring.
August 5th: A new report says that extreme heat & weather could kill 50x more people per yr in Europe by 2100 than today. That may be overestimate, but a more reasonable number in the report is that 2 out of every 3 Europeans will be affected by weather disasters (per year?) compared to 1 in 20 today. Heat waves will account for 99% of all the excess deaths predicted, and it’s awfully hard to relocate away from a heat wave.
August 4th: If you are not yet listening to @ourwarmregards smart & human commentary on climate change, what’s stopping you?
In January, I launched the #365climateimpacts project, in which I’ll spend a year tweeting stories of the many ways climate change is impacting people, ecosystems, and the earth; ideas for how to communicate about climate change more effectively; and analyses of technologies and policy proposals that show promise for combatting climate change. Here’s what I’ve shared in the last two weeks.
What does a graph like this mean? It means ocean is taking up heat that CO2 emissions would otherwise add to atmosphere.
I got a bit gif happy with today’s #365climateimpacts tweetstream, so you should really head over to twitter to enjoy the thread. I like snow. I like to sled, build snowmen, snowshoe, and how pretty snow is. Loss of snow is one reason I care about climate change. Today it is 57 F and raining steadily here in NE Ohio. I keep thinking about how we’d have a foot of snow if it were cold enough. Instead, I spent an hour in my class talking about the fun ways hydrologists have of measuring snow. With bare ground outside.
The average US snow season shortened by 2 weeks since 1972. Snow covered area is decreasing. The figure below is from the US EPA’s great Climate Change Indicators site, under the heading “Snow Cover.”
This figure shows the timing of each year’s snow cover season in the contiguous 48 states and Alaska, based on an average of all parts of the country that receive snow every year. The shaded band spans from the first date of snow cover until the last date of snow cover.
Climate normals say that my area averages 45″ of snow per winter, but I haven’t seen anywhere near that most of the 5 years I’ve lived here. Of course, 5 years isn’t long enough to identify any trend (I’m not arguing it is), but my experience fits in the pattern of less snowy winters that are being observed across the United States. Here’s some data stretching 60 years. The figure below is from the US EPA’s great Climate Change Indicators site, under the heading “Snowfall.” Red is less snow, more rain.
This figure shows the average rate of change in total snowfall from 1930 to 2007 at 419 weather stations in the contiguous 48 states. Blue circles represent increased snowfall; red circles represent a decrease.
February 8 (National Kite Flying Day):
Good morning, Twitter. It’s National Kite Flying Day! Do you think I can tie that to climate change?
President Obama has been appreciating kite flying, recently.
Back in the day, it wasn’t just surfboards powered by wind. It was big ships. Admittedly, with sails, not kites, but I’m doing the best I can to tie to #nationalkiteflyingday.
Modern shipping produces huge amounts of greenhouse gas emissions and wind is a renewable, carbon-free energy source. One idea is to attach big kites to ships to provide free & CO2-free energy.
It’s the middle of winter & something is seriously wrong with Arctic sea ice. Sea ice hit record low extents in November, December, and January. Nice reporting at Mashable by Andrew Freedman.
This figure shows the percentage of the land area of the contiguous 48 states where a much greater than normal portion of total annual precipitation has come from extreme single-day precipitation events. The bars represent individual years, while the line is a nine-year weighted average.
A “pineapple express” atmospheric river takes aim at California in December 2014. (NOAA/NASA GOES image)
Minnesota Public Radio ran a fantastic feature on how climate change is affecting ice cover on Lake Superior between Bayfield and Madeling Island, Wisconsin. For 250 year-round residents of the island, winter offers an ice road and the freedom to move back and forth without being tied to the ferry schedule. Except that, for two years running, the ice hasn’t been thick enough to drive on and the ferry has run all winter. This story is personal for me, because my family has owned land on Madeline Island for 4 generations, and I remember the thrill and terror of driving the ice road on winter visits.
The view from our family’s land on Madeline Island, February 3rd, 2017. Photo courtesy of J. Jarvis.
Our changing climate is already affecting lives in a multitude of ways, and the impacts of climate change will only increase as the world continues to heat up. But because climate operates in the background, it’s easy to ignore the magnitude of the changes happening around us, as we are caught up in a daily news cycle and the rhythms of our own lives. 2017 seems fated to be an eventful – and exhausting – year and it would be all too easy to put climate change on the back burner, while facing seemingly more urgent crises. But, the longer we avoid tackling climate change head on, the more dramatic the impacts we are going to be facing.
I quietly launched a new personal project in January, and now that I’m a month in, I’m ready to tell you about it. I’m tweeting one climate change story per day for each day in 2017, with the tag #365climateimpacts. I’m aiming to tweet timely news stories or compelling visualizations across a wide range of climate change impacted arenas, from oceans to ice, from food to energy, from policy to theology, and more. While I’ve tagged the tweets with the word impacts, I’ll cover climate science and climate solutions as well as the impacts of past, present, and future climate change.
My goals for this project are three-fold:
For those of us who are climate concerned, my goal is to keep climate change on the front burner of our collective agenda with daily reminders of the pervasiveness and magnitude of climate change implications and the hope that individual choice and policy and technological solutions have to offer.
For those who are climate cautious or disengaged, I hope that the in the diversity of topics I tweet at least one will make it across your timeline and resonate with you and the things you care about. We know that just piling on facts doesn’t change people’s minds, but finding a genuine connection is a first step towards a real dialogue. As much as a one-to-many, 140-character limited platform lets me do, I hope I connect with you at some point this year.
The term “Climate Change” is now loaded with so much political baggage that it becomes almost impossible to hold a discussion across political lines. In stakeholder interviews, people generally understand and acknowledge the impacts of climate change on local and regional scales, as long as you don’t call it “Climate Change”. This has been my experience working in rural coastal communities, which tend to be strongly conservative and intimately connected to the changing ocean.
Which is why, when I talk about Climate Change, I don’t talk about science.
When I talk about Climate Change, I talk about Fishing.
A warmer atmosphere can hold more water, so it’s not too surprising that the hottest year on record also had the most precipitable water in the atmosphere. Still it’s nice to see the physics theory borne out in the data.
Annual precipitable water in 2016 at the global scale was at record levels according to R1 Reanalysis (1948-present). pic.twitter.com/WRWNyYo1lT
Scientists like me study carbon emissions, deforestation, ocean acidification, desertification, sea-level rise, glacial melting, landscape degradation, groundwater salination, invasive species, global warming and more. There is very little good news to share. Today’s environmental problems are easily big enough to eclipse our inadequate solutions. When people tell me that climate change makes them feel hopeless, I breathe deep, and then I respond. I don’t answer them because I have a good response, but because we all deserve at least a bad response. Here is what I say.
The way I personally counter the despair that reading the latest climate change news can bring is by thinking about all of the technologies and solutions we already have in hand, and how the economics are steadily working ever more in their favor. President Obama makes a strong case for “The irreversible momentum of clean energy” in a policy forum article in Science magazine. I have a feeling Obama (2017) is going to be a highly cited paper over the next few years.
The mounting economic and scientific evidence leave me confident that trends toward a clean-energy economy that have emerged during my presidency will continue and that the economic opportunity for our country to harness that trend will only grow.
Days before handing over power to a Republican administration, the EPA managed to complete a mid-term review of greenhouse gas emissions standards for cars – more than a year ahead of schedule. Wired has the story:
By 2025, cars would have to nearly double their average fuel efficiency (a kind of measure of emissions) and deliver, on average, more than 50 miles per gallon (which, for arcane reasons, equates to a real world figure of 36 mpg). The auto industry caved and agreed, with the caveat that by April 2018, the EPA and National Highway Traffic Safety Administration do a thorough review of the rules, and adjust them if they proved unduly expensive or just plain unworkable.
By completing the review early – and finding the standards appropriate – the EPA just made it harder for the next administration to take a step backwards on car emissions.
There is, right now (as of Jan 12th), the least area of sea ice on our planet that we've ever measured—probably the lowest in millennia. pic.twitter.com/6LrUKxBEOF
There’s some debate over whether we should really be lumping the Arctic and Antarctic onto the same plot, but there’s no denying that this is a pretty stunning departure from recorded history of sea ice.
We knew it was coming, but January 18th is when NOAA and NASA confirmed that 2016 was the hottest year on record, beating out its immediate predecessor.
2016 was hottest year on record-again. They aren't anomalies. We can explain them w physics. Climate change is real. https://t.co/QXSmq06YkY
We show that over the past 50 years, the population of emperor penguins (Aptenodytes forsteri) in Terre Adélie has declined by 50% because of a decrease in adult survival during the late 1970s. At this time there was a prolonged abnormally warm period with reduced sea-ice extent. Mortality rates increased when warm sea-surface temperatures occurred in the foraging area and when annual sea-ice extent was reduced, and were higher for males than for females. In contrast with survival, emperor penguins hatched fewer eggs when winter sea-ice was extended. These results indicate strong and contrasting effects of large-scale oceanographic processes and sea-ice extent on the demography of emperor penguins, and their potential high susceptibility to climate change.
A stunning visualization of the trends in global temperature over the last 150 years in this temperature spiral, posted by Climate Central.
Global temperature spiral, updated to include 2016 data. Created by Ed Hawkins.
Climate change is already affecting Ohio. Find out how climate change affects your state, on this fantastic climate impacts site (produced by the Federal Government): https://statesummaries.ncics.org/ (Note: If this site disappears, I have copies of the info for the states where I’ve lived: OH, NC, OR, MN).
One of three key messages on climate change impacts being experienced by Ohio. The others focus on increasing temperature (and risks for urban areas) and increasing drought risks. What are the key messages for your state?
Unsure how things like volcanic eruptions and air pollution play into the climate change we are experiencing? This data visualization from Bloomberg does a nice job showing how we can’t explain historical temperature trends without CO2 emissions, and what roles other factors have been playing in the temperature record.
Peatlands are natural storehouse of carbon from the atmosphere — unless they are destroyed. Then, all the carbon goes back up into the atmosphere. Scientists have recently mapped a huge peatland in the Congo basin. It’s estimated to store the equivalent of 20 years worth of fossil fuel emissions from the United States, over an area the size of New York state. Let’s work to make sure it stays protected and the carbon stays in the ground.
Are you watching Katherine Hayhoe’s Global Weirding series of videos yet? You should. One thing I love about Dr. Hayhoe is how clearly she explains why a “just the facts” approach won’t work to convince people skeptical of climate change’s reality. That’s the focus of the latest episode of her series.
Average change in population affected per country given 4?C global warming. Hatching indicates countries where the confidence level of the average change is less than 90%. Figure copyright EU, used in spirit of fair use.
In a month filled with signs that the new US administration will roll back federal comittments to combatting climate change, California is a beacon of light. The state of California, one of the world’s largest economies in it’s own right, is continuing forward with its efforts to decrease its greenhouse gas emissions. As California knows, once the groundwork for a low carbon future is laid, the economics of going backward don’t make sense.
“There’s a whole ecosystem built to reduce emissions,” said Jon Costantino, an environmental policy advisor who previously worked at the California Air Resources Board. “There’s investors, there’s businesses, there’s consultants.”
He added, “To pull the rug out from under that would have a dramatic impact.”
Back in mid-April, I was invited to do an AGU-facilitated Ask Me Anything on r/AskScienceDiscussion/ along with Dr. Kim Cobb. Here’s how we introduced ourselves:
AGU AMA: I’m Dr. Kim Cobb, and I’m here to talk about the science of climate change, El Niño, and the reconstruction of past climate. And I’m Dr. Anne Jefferson, and I’m here to talk about how water moves through landscapes and how land use and climate change alter hydrology. Ask Us Anything!
We got fantastic questions and did our best to answer what we could. I encourage you to dip into the questions and answers and see for yourself.
This position has been filled. Thanks for your interest.
Post-doctoral Associate in Watershed Modeling
A post-doctoral position focusing on hydrologic modeling of urban watersheds is available in the Department of Geology, Kent State University, in the lab of Anne Jefferson (http://all-geo.org/jefferson/research/). The successful candidate will have experience using RHESSys or another distributed watershed model and interest in applying their skills to questions about the effects of green infrastructure and climate change in urban areas. The post-doc will be expected to contribute to research design and undertaking, publication, and pursuit of external funding. There will also be the potential to develop additional projects building on the strengths, interests, and expertise of the successful candidate. The post-doc will have access to a wealth of data sets, field sites and instrumentation; an interdisciplinary, collaborative group of researchers and external partners focused on urban ecosystems; and a campus mentoring program for postdocs.
Kent State University (www.kent.edu), the second largest university in Ohio, is a state-supported, doctoral degree granting institution ranked as ‘high research’ by the Carnegie Foundation. The Department of Geology (www.kent.edu/geology/) has a strong graduate program (both MS and Ph.D. degrees) in both applied and basic areas of geologic research. The city of Kent combines the eclectic atmosphere of a small midwest college town with easy access to major metropolitan centers, including Cleveland, Akron, Columbus, and Pittsburgh.
Salary will be commensurate with experience and includes a competitive benefits package. Funding is initially available to support 1.5 years of work and opportunities will be sought to extend the support. If you are interested in learning more about the position, e mail Anne Jefferson (ajeffer9 at kent edu) with your CV, a description of your interests and experiences, and contact information for three people willing to serve as references. Review of applications will begin March 1st and continue until the position is filled. Kent State University is an Affirmative Action/Equal Opportunity Employer and encourages interest from candidates who would enhance the diversity of the University’s faculty.
In maritime mountainous regions, the phase of winter precipitation is elevation dependent, and in watersheds receiving both rain and snow, hydrologic impacts of climate change are less straightforward than in snowmelt-dominated systems. Here, 29 Pacific Northwest watersheds illustrate how distribution of seasonal snow, transient snow, and winter rain mediates sensitivity to 20th century warming. Watersheds with >50% of their area in the seasonal snow zone had significant (? ? 0.1) trends towards greater winter and lower summer discharge, while lower elevations had no consistent trends. In seasonal snow-dominated watersheds, runoff occurs 22–27 days earlier and minimum flows are 5–9% lower than in 1962, based on Sen’s slope over the period. Trends in peak streamflow depend on whether watershed area susceptible to rain-on-snow events is increasing or decreasing. Delineation of elevation-dependent snow zones identifies climate sensitivity of maritime mountainous watersheds and enables planning for water and ecosystem impacts of climate change.
Unusually heavy monsoon rains in July and August 2010 left large swaths of Pakistan underwater. At least 18 million people were affected by the flood, and it is estimated that, more than six months later, several hundred thousand remain without even temporary shelter. As a result of lost crops and livelihoods from the flood and inadequate relief supplies, malnutrition continues to kill people. Like most floods, the Pakistani poor have suffered far more than those with resources to avoid the flood, or at least its aftermath.
Remains of a school destroyed by flooding, near Jacobabad by UK Department for International Development, on Flickr. Used under a Creative Commons license.
A paper in press in Geophysical Research Letters shows that the 2010 floods were extraordinary. Monsoonal rains tend to occur in pulses, with multi-day wet periods followed by multi-day dry periods, and while the total rainfall over Pakistan during the 2010 monsoon season was not unprecedented, the number and intensity of extremely heavy rains over northern Pakistan was very unusual. The authors are working with very limited historical and satellite data, but they estimate that the number of intense rain bursts that occurred in 2010 had a probability of less than 3% in any given year.
Using data from the European Centre for Medium Range Weather Forecasts collection of meteorological models, the authors of the new paper show that the timing and intensity of northern Pakistan’s monsoon rain bursts are predictable up to 6 to 8 days in advance – including the rains that caused the flooding in 2010.
Lead author, Peter Webster, and his coauthors from the Georgia Institute of Technology, draw the following conclusion from their analysis:
We conclude that if these extended quantitative precipitation forecasts had been available in Pakistan, the high risk of flooding could have been foreseen. If these rainfall forecasts had been coupled to a hydrological model then the high risk of extensive and prolonged flooding could have anticipated and actions taken to mitigate their impact.
The floods really kicked off with a burst of rain on 28-29 July 2010, and according to Webster’s reanalysis, that rainfall was predictable with good skill 7 days in advance (21 July). Webster and colleagues argue that if that forecast was available in Pakistan, lives would have been saved and the immensity of the disaster reduced. But, C. Christine Fair, writing on the Foreign Policy magazine website suggests that the flood was forecast in Pakistan.
In the middle of July, the PMD began tracking a storm brewing in the Bay of Bengal. This eastern weather system developed interactively with a western weather system to produce the massive rains and the subsequent super flood of 2010. On July 24, the PMD issued a flood warning to the provincial government of Khyber-Pakhtunkhwa (KPK). Despite these increasingly severe warnings, KPK’s citizenry did not believe them. … The PMD kept issuing warnings to KPK as the rains began to fall. However, as fate would have it, on July 28, … a passenger jet coming to Islamabad from Karachi crashed …With the media beset upon this tragic spectacle, the PMD’s warnings went unheeded as the rain began to fall.
So the Pakistani government did forecast the flood – at least four days out – in plenty of time to get people in northern Pakistan’s valleys out of the way. The problem was not with the meteorological and hydrologic science either internationally or in Pakistan. Instead, disaster was ensured when flood warnings were not taken sufficiently seriously by regional authorities, media, and residents.
Why wouldn’t flood warnings be heeded? Perhaps more could have been done to communicate to Pakistanis through channels whose authority they respected. Webster cites an example of flood warnings in Bangladesh being disseminated by imams at local mosques. The Foreign Policy article quoted above places some blame on media distractedness.
But there was also a more insidious reason the forecasted flood was ignored. It was a rare event, but it was also part of a new climatic pattern for Pakistan. As the Foreign Policy article describes it:
in recent years there has been a slow but steady change in the location where Pakistan’s major rainfalls concentrate. In the past, monsoon rains fell most intensely over the Punjab. Slowly and steadily, the concentration of rainfall has moved north and west to KPK. This redistribution of concentrated rainfall away from the Punjab and towards KPK explains why no one in KPK had any reason to believe the predicted weather.
Flooding frequency and intensity have increased in Pakistan in the last 30-40 years compared to earlier in the 20th century. Webster and coauthors state, “This recent increase is consistent with the increase in intensity of the global monsoon accompanying the last three decades of general global warming.” The flood warnings were ignored, in part, because the statistics of monsoon rain patterns are changing. Human memory and historical records are not good guidance if the weather system is changing. In situations like this one, the past is not the key to the present.
There are lots of things that should have been improved to lessen the magnitude of the Pakistani flood disaster – reservoir management should have been altered; emergency relief supplies should have been distributed more equitably, broadly, and consistently; international assistance should have been much more generous – but the two big lessons for hazard mitigation coming out of the Pakistan floods seem to be: “find a system for making sure that warnings are issued and that they actually make it to people in harm’s way” and “don’t assume the climate of living memory is a very good indicator of the weather of the present and future.”
Webster, P. J., Toma, V.E., & Kim, H.-M. (2011). Were the 2010 Pakistan floods predictable? Geophysical Research Letters : 10.1029/2010GL046346
Cross-posted at Highly Allochthonous
Here in Charlotte we had a hot summer. We barely escaped the dubious distinction of hottest summer on record, with an average temperature of 81.1° F (27.3 ° C) between 1 June and 31 August. The record had been set in 1993, when Charlotte recorded an average temperature of 81.5° F (27.5 ° C). In terms of record breaking heat, we actually fared better than many parts of the east coast, where temperature records from New York City to Greenville-Spartanburg, South Carolina were broken. Below there’s a nice map from NOAA of how far average temperatures deviated from the 30-year climate normal period (here, 1966-1996).
U.S. surface temperature departure from average (°C), June 1 to August 31, 2010, from NOAA/ESRL Physical Sciences Division, Boulder Colorado
Of course those average temperature records belie the minima and maxima experienced by each place over the course of those three summer months, so there’s another statistic that I’m finding even more interesting: the number of days where maximum temperatures exceeded 90° F (32.2 ° C). I think of it as Anne’s index of intolerable heat, especially when combined with the Southeast’s oppressive humidity. In Charlotte, between 1 June and 31 August, we had 67 days that exceeded 90° F. That means that 73% of days this summer were intolerably hot (at least for me). Also, that’s only counting the days in the climatological summer. We had 90+° F degree heat in early April, some in May, and we’ve already had some in September, with more in the forecast this week. I suspect that by the time the year is out, our total days above 90° F will be something around 80, if not more.
The long-term predictions for the index of intolerable heat look grim for Charlotte and the rest of the southeast. The image below shows historical and modeled days with peak temperatures exceeding 90° F. By the end of the century, at least under a high emissions scenario, 80+ days of intolerable heat will be considered a cool summer in North Carolina. We’re heading towards 120 days or more of hot, hot weather, a doubling of our historical average. In parts of Florida and Texas, more than half the year will be hotter than 90° F. Yuck. Glad I won’t be around here then.
These temperature trends are not just bad news for people who like to play (or do field work) outside in the summer, but are too wimpy to drop bucketloads of sweat. Hotter average temperatures and more days with ridiculous heat have real health consequences. On hot days, the chances go up that people playing outside end up with heat exhaustion or life-threatening heat stroke. People without air conditioned homes or workplaces, people too poor to pay tremendous energy bills for air conditioning, or people who just happen to have their AC break do not even need to play outside to be at risk of heat related illness or death. About 700 people already die each year from heat-related causes, and the elderly are a disproportionate share of the victims. Those with cardiovascular disease are also at substantially increased risk of heat-related mortality.
And it’s not the heat alone that spells bad news for the Southeast. With hotter temperatures come increasing rates of photochemical reactions…such as the production of ground-level ozone from nitrous oxides and volatile organic compounds released by car exhaust, power plants, and natural sources. The chemistryof photochemical ozone production is pretty complex and we don’t have a fantastic handle on how coming climate changes will impact the percent of hot days with sun versus clouds, but if the number of hot sunny days increases, it is likely that ozone production will increase too. Ozone brings its own host of adverse health effects, particularly respiratory problems, so even if you don’t mind the heat, running around outside on hot, sunny days can be a bad idea. Once again, children, the elderly, and those with asthma and other respiratory problems are most at risk on high ozone days. Such days, labeled as orange alerts, occur sporadically thoughout the summer already. In Charlotte, we’ve had 13 days with air quality in the orange category since May 1 this year. On those days, people at risk are encouraged to avoid outdoor exercise, and daycare centers limit the time kids spent playing outside. Some days, the air quality is bad enough (red alert) that even healthy adults are encouraged to avoid to outdoor exercise. That’s happened once this year in Charlotte.
As Charlotte and other parts of the southeast move towards one-third of their days in the intolerably hot range, with the probable added bonus of worse air pollution, it will be interesting to watch the societal shifts in attitudes toward the climate. Will Southerners get serious about reducing emissions from cars? Will Charlotteans end their love affair with sprawl in order to improve air quality? Will the Southeast be depopulated of Yankee transplants like me, who finally decide that they can’t take the heat? Or will we just stay inside and crank up the air conditioning units and complain about the weather?
How the world’s biggest river basins are going to respond to mid-century climate change…and how large reservoirs affect our measurements of global sea level rise.
Immerzeel, W., van Beek, L., & Bierkens, M. (2010). Climate Change Will Affect the Asian Water Towers Science, 328 (5984), 1382-1385 DOI: 10.1126/science.1183188
Where do 1 in 4 people live? Where do those people get their water? 1.4 billion people live in five river basins (Indus, Ganges, Brahmaputra, Yangtze, and Yellow) and those mighty rivers source some of their water in the Himalayas, where on-going climate change will have a big impact on glacier melt and seasonal precipitation. In this paper, Immerzeel and colleagues used the SRM hydrologic model and GCM outputs to simulate the years 2046-2065 under two different glacier extent scenarios, a “best-guess” and an extreme case where all glacier cover had disappeared. The five basins all behaved quite differently from each other, because each basin has a different topographic distribution. The Brahmaputra and Indus have the highest percent of glacier-covered area, and these two rivers will be the most severely impacted by projected climate change via decreases in late spring and summer streamflow, as reduced glacier melt is only partially offset by increased spring rains. Between these two basins, the authors estimate that the hydrologic changes will reduce the number of people who can be fed by 60 million people! On the other hand, basins with less reliance on meltwater will not be as bad off – in fact, the Yellow River is likely to experience an increase in spring streamflow and may be able to feed 3 million more people. To me this paper emphasizes the fact that the consequences of climate change are not going to be evenly dispensed across the world’s population and that we’ve really got an urgent task of figuring out how regional climate changes will cascade through hydrology, ecology, food security, disease, and almost every other aspect of the world on which we depend.
Fiedler, J., & Conrad, C. (2010). Spatial variability of sea level rise due to water impoundment behind dams Geophysical Research Letters, 37 (12) DOI: 10.1029/2010GL043462
Global reservoirs trap ~10,800 cubic kilometers of water – enough volume to reduce sea level by ~30 mm. But when large reservoirs are filled, the water weight locally depresses the Earth’s surface and increases local relative sea level. Thus, tide gages that are close to large reservoirs don’t record the true sea level effects of water impoundment – instead recording only about 60% of the true drop. This creates an added wrinkle in the estimation of global sea level rise over the last century, and Fiedler and Conrad compute that these reservoir effects on the geoid have caused an ~10% over-estimation in rates of sea level rise. The largest effects on sea level rise records are places where tide gages are near big reservoirs – like the east coast of North America. *
* Please note that I can’t read the full article of AGU publications (including WRR, JGR, and GRL) until July 2010 or the print issue arrives in my institution’s library. Summaries of those articles are based on the abstract only.