During the extreme heat waves and droughts of the early 1980s, climatologist James Hansen noticed coincident public discussions about the possible link of extreme events to climate change. He says discussion cooled, however, when natural variability turned up a season with average or cold temperatures. In 1988, another heat wave and drought wiped out crops in the U.S. Midwest, and resulted in more than 5,000 deaths, according to NOAA’s National Climatic Data Center. That same year, Hansen introduced the analogy of loaded dice to demonstrate variability and the growing frequency of extreme temperature events.

On one of the six-sided dice, Hansen painted two sides blue, two sides white, and two sides red to represent the chance of a cold, average, or warm summer season, respectively. That’s how the dice would have rolled from 1951 to 1980, when climate was relatively stable. On the other die – this one loaded – Hansen painted one side blue, one side white, and four sides red. That’s how climate models suggested the dice would roll by the first decade of the 21st century, should the increase of greenhouse gases in the atmosphere play out as it did.

"If you keep track for several seasons you notice the frequency of the anomalies has now changed, and you’re getting much more of those on the warm side than on the cool side," Hansen says.

The changes that Hansen and colleagues calculated in 1988 turned out to be close to reality, as far as how many sides of the dice would now be red as opposed to blue to represent today's climate. But a key difference between the 1988 dice and the new climate dice is the addition of an entirely new color. Almost one full side previously red is now brown, representing a new category of extreme hot events.

"I didn’t think about adding another color in 1988," Hansen says. "Since then I have realized that the extreme cases are the most interesting and hold the most potential for impact, such as we’re seeing this summer in the case of the drought and devastated corn crop."

The division between warm and cool will continue to change in the future, Hansen says. "But it’s still a crapshoot and you shouldn’t take one cool season as an indication that there’s something wrong with our understanding of global temperature and warming."

Hansen and colleagues continue to use the dice for communication purposes, but they now employ a different statistical tool – the bell curve – that they say better demonstrates the change in temperature anomalies, particularly at the extremes.

Text by Kathryn Hansen. Top image: James Hansen of NASA's Goddard Institute for Space Studies. Credit: NASA

Changes in rainfall affect more than just land-based ecosystems. New research shows that increased rainfall in Maine led to the decline of ocean dwelling plant-like organisms called phytoplankton, which make up the base of the oceanic food web.

Researchers led by William Balch, of Bigelow Laboratory for Ocean Sciences in East Boothbay, Maine, found that more rainfall translates into more river runoff flowing into the Gulf of Maine. The runoff, in turn, prevents phytoplankton from receiving the nutrients and light they need to thrive, researchers reported March 29 in Marine Ecology Progress Series. Read the study here, and Bigelow Laboratory’s story here.

“We demonstrated a massive, five-fold drop in primary production in this region — along with other big changes — associated with the record-breaking precipitation events that started in the mid-2000's,” Balch said.

The researchers combined climate and river flow data with the results from a 12-year time series collected during the NASA-funded Gulf of Maine North Atlantic Time Series (GNATS) project. Between 1998 and 2010, GNATS documented changes in nutrient concentrations, phytoplankton biomass, and carbon fixation between Portland, Maine and Yarmouth, Nova Scotia (see map, below).

“We combined climate data from over a century, river run-off data and the coastal time series to show how intimately the coastal ecosystem is connected to hydrological processes on land,” Balch said.

It remains to be seen how the shift in the base of the food web will trickle up to impact the Gulf of Maine’s fish, lobster, and the endangered North Atlantic right whale, which has been known to feed in the Gulf.

Text by Kathryn Hansen. Top image: William Balch collects temperature measurements from the Gulf of Maine. Credit: Globe Staff / Dina Rudick. For related images, check out The Boston Globe’s “Climate Change in the Ocean” gallery.

Bottom image: Data from NASA’s Sea-viewing Wide Field-of-view Sensor shows areas in the Gulf of Maine that on May 11, 2002, exhibited the high chlorophyll concentrations (red and orange) that mark thriving phytoplankton populations. New research shows that increased rainfall and river runoff caused phytoplankton to decrease five-fold since the mid-2000s. Credit: NASA

EarthSky has named Gavin Schmidt, a climate modeler based at NASA's Goddard Institute for Space Studies its science communicator of the year. The first question of an eight minute EarthSky podcast Q & A with Schmidt is below. Listen to the rest of the interview here and see more of Gavin's appearances in the media here. 

Give us a sense of what’s really happening with climate change on our planet right now.
I think you want to side-step that question and talk about what people are doing to study this problem. Who are these people who are going out and measuring ocean temperatures? Who are these people who are tracking the year-on-year retreat of the Arctic sea ice? Who are these people who are going out and measuring the small processes involved in cloud formation, in soil moisture retention, in ocean eddies, in evaporation? It’s these things that we then put together to build the numerical simulations that I work on, these climate models, that we’re using to help us piece together what’s happened in the past, what’s happening now, and what’s likely to happen in the future. I think it’s far more important that people get a sense of the science as a work in progress, rather than one particular message or piece of content knowledge getting hammered home.

A new, updated map reveals how the Antarctic continent looks under the ice, detailing each mountain range and valley. Beyond its undeniable beauty, this high-resolution map of Antarctica’s bed topography, dubbed BEDMAP2, will help scientists model how ice sheets and glaciers respond to changes in the environment.

A large international consortium of Antarctic field programs, including NASA IceBridge, contributed information to this updated map of bed elevation and ice thickness for Antarctica and the Southern Ocean. The first version of BEDMAP was completed in 2000. The new version, which was presented on Dec. 5 at the American Geophysical Union’s 2011 Fall Meeting, incorporates seismic and radar data from about 265,000 km of airborne surveys over the ice.

“We are lacking fundamental data on ice thickness and bedrock elevation over large parts of Antarctica, because these areas are hard to reach,” said IceBridge project scientist Michael Studinger. “We’ll continue to fill in critical information gaps on places such as the Recovery Glacier in Coats Land, East Antarctica. This area has long been on the wish list of ice sheet modelers, but it is very far away from all research bases.”

This year, IceBridge’s DC-8 aircraft was able to fly four times over Recovery Glacier from Punta Arenas, Chile. “We have collected a landmark data set that will fill a critical hole in new BEDMAP compilations,” Studinger said.

Text by Maria-José Viñas. Image courtesy of the BEDMAP Consortium. The new version of BEDMAP will soon be freely available. Read more about the BEDMAP2 on the project’s website.

To understand how the Antarctic ice sheet is going to behave in the future, scientists first need to know how much snow and ice is in there. And a major step in determining that figure is calculating how much snow accumulates each year on the frozen continent.

Researchers from the Satellite Era Accumulation Traverse (SEAT) are extracting ice cores in central West Antarctica to update snow accumulation records, since the majority of previously collected cores only extend to the mid-1990s. The scientists analyzed three of the five cores collected during their 2010-2011 field campaign, and their preliminary results show that snow accumulation has decreased significantly (up to 40 percent) across central West Antarctica during the last decade.

"This is the opposite of what you’d expect at a time when there’s a significant warming of West Antarctica," says Landon Burgener, of the SEAT team, who presented the group’s preliminary results at the American Geophysical Union’s Fall Meeting.

Higher temperatures mean higher water evaporation, which in theory should lead to more snowfall. The measured decrease in snow accumulation goes against the predictions of global climate models, so why is it happening? It might have to do with less frequent, weaker storms in the area, says Summer Rupper, one of the principal investigators of the SEAT project. Less storms means that the extra moisture in the atmosphere ends up falling back to Earth somewhere else, probably over the ocean. Next, the team will examine the (scarce) existing weather data for West Antarctica to see if it’s true that the area is becoming less stormy. Rupper also wants to use ground-based radar data to study how representative the cores are of the places where they were extracted.

Meanwhile, other members of the SEAT team are currently in Antarctica to collect eight more cores that they will analyze to see if they also show a decline in snow accumulation.

Text by Maria-José Viñas. Photo and map courtesy of the SEAT team: The photo (top) shows members of the team drilling an ice core during the 2010-2011 season; the map (above) shows the drilling sites in central West Antarctica. Follow the work of the SEAT researchers in Antarctica on their blog, "Notes from the field."