The Washington PostDemocracy Dies in Darkness

Scientists react to warmest year: 2014 underscores ‘undeniable fact’ of human-caused climate change

Temperature difference from normal in 2014 from NASA.

In 134 years of temperature records, the warmth in 2014 exceeded them all, NOAA and NASA announced today.

Unsurpassed heating of the world’s oceans fueled the chart-topping warmth.

Ocean temperatures were more than 1 F above average, NOAA said.  They warmed to a new record even in the absence of an El Niño event, a naturally occurring cycle of ocean heating in the tropical Pacific.

“This is the first year since 1997 that the record warmest year was not an El Niño year at the beginning of the year, because the last three have been,”  Gavin Schmidt, who directs the NASA Goddard Institute for Space Studies, told the Post’s Chris Mooney.

Related: It’s official: 2014 was the hottest year in recorded history (Washington Post Wonk Blog)

Land temperatures weren’t quite record-setting, but still ranked 4th warmest since the start of the data set in 1880. California, much of Europe, including the United Kingdom, and parts of Australia all experienced their warmest years.

News of record global warmth may surprise residents of the eastern U.S., which witnessed colder than normal temperatures in 2014. But the chill was an anomaly and, in fact, the eastern U.S. was among the coolest areas of the world compared to normal.

In NOAA’s analysis of global temperatures, 7 of 12 months in 2014 reached record highs, including December.

Thirteen of the warmest 15 years on record have occurred since the year 2000 according to Climate Central, a non-profit science communications organization based in Princeton, New Jersey. The likelihood of this happening by chance, with the assistance of manmade greenhouse emissions, is less than 1 in 27 million, it calculated.

Twenty-one scientists respond

So what do the 2014 temperatures released thus far signify?

I queried 21 climate scientists. Most replied the record matches exactly what we should expect in a warming world as more and more heat-trapping greenhouse gases accumulate in the atmosphere. But a few were unimpressed, expressing the view that warming – while real – has not kept pace with projections from climate models and that one should not read too much into the temperature of a single year.

Below, I share with you their reactions – starting with those who seemed most moved by today’s news, and concluding with those who were somewhat underwhelmed.  I have attempted to bin the comments by common theme.

Some of these responses were edited for length.

2014 is what global warming looks like and portends a growing human influence on the climate

“The global warmth of 2014 is just another reminder that the planet is warming and warming fast. Perhaps most remarkable is that this level of warmth was achieved without the expected large El Niño.”

“Humans, and their burning of fossil fuels, are dominating the Earth’s climate system like never before. Just as scary, perhaps, is the way record 2014 heat baked the drought parched Southwest U.S. and California, and in doing so, made the drought impacts worse than they would have been without human impacts on the climate system. 2014 was one for the record books in many ways, and it serves as a great illustration of what global warming is all about.”

— Jonathan Overpeck, co-director, Institute of the Environment, Arizona State University

“The temperature record is yet another brick in the massive wall of evidence that the climate is warming due to human activity. Of the twenty warmest years in recorded history, nineteen happened in the past two decades. Our entire idea of ‘normal’ is changing. The students in my classes live in a climate that is warmer than the one in which I was raised, just as my world as a child was warmer than the one in which my parents were raised. Talk about a generation gap!”

— Simon Donner, associate professor of climatology, University of British Columbia

“The fact that NOAA rated 2014 as the warmest year on record should put to rest the bogus idea often espoused by climate change deniers that ‘global warming stopped in 1998.’ Based on the evidence, more than 97 percent of climate scientists have concluded that humans are primarily responsible for the warming of the planet to the record levels observed in 2014.”

“Climate change is already causing significant impacts to people and ecosystems, and these impacts will grow much more severe in the coming years. As we approach the critical negotiations in Paris in December to hammer out a new binding climate change treaty, we should keep in mind that we can choose to take economically sensible steps to lessen the damage of climate change, and the cost of inaction is much higher than the cost of action.”

— Jeff Masters, director of meteorology at Weather Underground, and Bob Henson, author “The Thinking Person’s Guide to Climate Change”

“Viewed in context, the record 2014 temperatures underscore the undeniable fact that we are witnessing, before our eyes, the effects of human-caused climate change. It is exceptionally unlikely that we would be seeing a record year, during a record warm decade, during a multidecadal period of warmth that appears to be unrivaled over at least the past millennium—if it were not for the rising levels of planet-warming gases produced by fossil fuel burning.”

“The record temperatures *should* put to rest the absurd notion of a “pause” (what I refer to as the “Faux Pause” in Scientific American) in global warming. Human-caused warming of the globe and associated changes in our climate continue unabated as we continue to raise the concentrations of greenhouse gases in the atmosphere.”

— Michael Mann, distinguished professor, department of meteorology, Penn State University

“This is yet another reminder that global warming continues apace. Climate change is no longer a challenge facing future generations: we are experiencing its impacts today. Not only that, but we will continue to see these records being broken, year after year, until we are able to wean ourselves off our addiction to dirty, old-fashioned fossil fuels.”

— Katharine Hayhoe, professor of atmospheric sciences, Texas Tech University

“If you are younger than 29-years old, you haven’t lived in a month that was cooler than the 20th century average. That’s a new normal that is a result of human activities on top of the natural varying climate that has global temperature trends moving very quickly towards a 1-2 C increase. While that may sound insignificant, it’s best to think of it as the difference between a low-grade fever and one just a few degrees higher that can have an impact on the body.”

Marshall Shepherd, director for program in atmospheric science, University of Georgia

“Global mean temperature is a fairly abstract concept to most of us: we relate to climate through direct experience, so if we remember a cold spell last year that may seem more pertinent or convincing than the global mean temperature. From a physics perspective the global mean temperature represents lots of interesting processes – rising greenhouse gases among them – and setting a record like this means those processes lined up this year. Rising greenhouse gases make each year roughly .04 degrees F warmer than the last, which really adds up over time.”

“Clearly the hiatus is over!”

— Philip Mote, director, Oregon Climate Change Research Institute, Oregon State University

“This comes as no surprise. We routinely measure carbon dioxide that’s produced from the burning of fossil fuels and it has been increasing in the atmosphere. We also know that internal variability of the climate system has slowed the surface warming trend since 2000 but the subsurface ocean has continued to warm. Eventually the warming from increasing carbon dioxide pushes the global surface temperature higher in the long term. And this is GLOBAL warming, and is a global average.”

“Thus, there are some areas that are warmer than the global average and some that are cooler, just as the western U.S. was quite warm in 2014 while the eastern U.S. was relatively cool. But climate is all about averages, both over time and over all the earth’s surface, and last year was, in the global average, the warmest on record. And 2015 may not be warmer than 2014, but over the next decade it will likely be warmer on average than the previous decade. This is a product of how the climate system responds to ever-increasing amounts of human-produced CO2 in the atmosphere.”

— Gerald Meehl, senior scientist, National Center for Atmospheric Research

“The 2014 global temperature information is simply the latest piece of evidence that helps confirm what most climate scientists have known for over a century:  higher amounts of greenhouse gasses lead, over time, to warmer temperatures at the earth’s surface.”

“These higher air and ocean temperatures ‘speed up’ the water cycle, leading to both increased droughts and floods, more intense rainfall, and potentially stronger hurricanes and typhoons.”

“These changes to our weather and climate affect not only the environment, but all of us, forcing us to either adapt to these more extreme periods of heat, floods and drought, or to suffer the consequences.”

“When will this trend end?  Only when we resolve to stop dumping excessive greenhouse gasses into the atmosphere.”

— David Titley, director for Center for Solutions to Weather and Climate Risk, Penn State University

“With human influences on climate clearly continuing through increases in carbon dioxide to over 400 ppm, it is not surprising that 2014 sets a new record for global mean surface temperature. However, if 2014 is the warmest year on record it won’t be by much. Other records may not have it as warmest on record and the small differences relate to how complete the Arctic region is in the entire record.”

— Kevin Trenberth, distinguished senior scientist, National Center for Atmospheric Research

Global warming is not necessarily what’s happening in your backyard

“Washington, D.C. happens to be located in one of the few places on Earth that was cooler than normal in 2014, which may be why so many members of Congress think human-caused global warming is not happening.”

“A new record for the globe’s temperature is an important and expected milestone, but the related regional climate changes are having immediate and profound effects on society: heat waves, prolonged drought, rising sea levels, and more frequent heavy downpours.”

— Jennifer Francis, research professor, Rutgers University

“Looking at the big picture of Earth’s climate over many decades, 2014 is the new “leader of the pack” of the last 38 years, all of which have been relatively warm. Taken together, the warm temperatures of the recent decades demonstrate the impact of greenhouse gases on our climate, and invalidate the sound bite that global warming has somehow ‘stopped.’

“The 2014 record also shows us that what happens in our backyard can be different than the rest of the world. Even though the 2014 temperature for the D.C. region may have been slightly colder than average, that was not the case for most of the rest of the planet.”

— Joe Casola, program director for science and impacts at the Center for Climate and Energy Solutions

2014 is only one year and global temperature is just one indicator, but part of larger picture of global change

“There are several key aspects to this. One is that it is surprising that this would be the warmest year despite there being no El Nino and this having a period of slower temperature change apparently because of the effect of natural ocean cyclic effects. Another point is that warming temperatures are just one of the indicators of the changing climate — I am much more concerned about sea level rise and the changing trends in severe weather events in terms of their effects on humanity.”

— Don Wuebbles, professor of atmospheric sciences, University of Illinois

“The fact that 2014 represents a new record warmest year is, in isolation, not particularly remarkable. A single year of record-breaking temperatures does not prove the existence of anthropogenic climate change, just as a single relatively cold year does not disprove it. However, the fact that the three warmest years on record have occurred in the last decade – itself the warmest decade on record – provides evidence of steady warming caused by greenhouse gases in the atmosphere. Simply put, record-breaking temperatures are the new normal.”

— Kim Cobb, professor of paleoclimate, Georgia Institute of Technology

“As the saying goes, one record hot year doesn’t make a global warming trend. However, the repeated setting of new record high temperatures in 2014, 2010, 2005, 1998 and 1997 is clear indication of ongoing global warming. Using NOAA data, a new record cold year globally has not been set since 1911!”

— David Karoly, professor of meteorology, University of Melbourne, Australia

“I think it is a mistake to focus on single years, whether they be cold or hot. Other than that, I have no particular opinion.”

— Kerry Emanuel, professor of atmospheric science, Massachusetts Institute of Technology 

Don’t focus on global temperature

“Although the global temperature is being reported as the warmest on record, that was NOT true for much of the lower-48 states. In fact, the eastern two-thirds of the U.S. was below normal, with unusually cold temperatures over the Northern Plains and around the Great Lakes.”

“Warmer than normal temperatures were centered over California and the Desert Southwest. The moral of the story is that global warming is never globally uniform, with varying areas experiencing profoundly different extremes.”

— Cliff Mass, professor of atmospheric sciences, University of Washington

“There remain significant uncertainties in the accuracy of the land portion of the surface temperature data, where we have found a significant warm bias. Thus, the reported global average surface temperature anomaly is also too warm.”

“More generally, we need to move beyond just assessing global warming, but examine how (and if) key atmospheric and ocean circulations, such as El Nino, La Nina, the Pacific Decadal Oscillation, ect are changing in their intensity, structure and frequency. These are the climate features that determine if a region has drought, floods, and so forth, not a global average surface temperature anomaly.”

— Roger Pielke, Sr., professor of atmospheric science, Colorado State University

Recent warming trends are less than forecast by computer models

“With 2014 essentially tied with 2005 and 2010 for hottest year, this implies that there has been essentially no trend in warming over the past decade. This ‘almost’ record year does not help the growing discrepancy between the climate model projections and the surface temperature observations.”

— Judith Curry, professor in school of earth and atmospheric sciences, Georgia Institute of Technology

“Whether or not a given year is a hundredth of a degree or so above a previous record is not the issue. What IS the issue is how observed temperatures compare to what has been forecast to happen.”

“John Christy and Richard McNider, from University of Alabama (Huntsville) recently compared climate model projections to observed lower atmospheric temperatures as measured by two independent sources: satellites and weather balloons. They found that the average warming predicted to have occurred since 1979 (when the satellite data starts) is approximately three times larger than what is being observed.”

— Pat Michaels, director of the Center for the Study of Science at the Cato Institute

“The satellite and balloon data of the deep atmosphere have 2014 in a cluster of warmish years well below the hottest two of 1998 and 2010. With the government agencies reporting that the surface temperature as highest ever, we have a puzzle. The puzzle is even more puzzling because theory (i.e. models) indicate the opposite should be occurring – greater warmth in the deep atmosphere than the surface. So, there are just many very basic and fundamental aspects of the global climate we have yet to comprehend.”

John Christy, professor of atmospheric sciences, University of Alabama-Huntsville

NOAA and NASA join the Japan Meteorological Agency and Berkeley Earth, an independent group of U.S. climate analysts, in their determination that 2014 was the warmest year on record for the planet.

This era of record-setting warmth coincides with carbon dioxide levels higher than at any time in at least 800,000 years. The current concentration is just above 400 parts per million, more than 40 percent above pre-industrial levels.

2014 did not run away with the warm temperature record, only besting trailing years by a hair. In fact, the Berkeley Earth scientists said the average temperature of 2014 was statistically indistinguishable from the two other warmest years on record, 2010 and 2005.

Not every temperature record shows 2014 as the warmest. Though not quite an apples to apples comparison, the estimate of the lower atmosphere (troposphere) temperature from weather satellites (which extend back to 1979) from the University of Alabama-Huntsville, ranked 2014 as the third warmest year on record, behind 1998 and 2010.  The Hadley Centre in the United Kingdom, which also analyzes global temperatures, has yet to release its results.