Category: Ocean Warming

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Ocean warming doubles in recent decades

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Lawrence Livermore, NOAA and partner scientists quantify heat accumulating in global ocean

Editor’s note: The following web story was provided by Lawrence Livermore National Laboratory. The original story can be found by clicking here on the Lawrence Livermore website.

Lawrence Livermore National Laboratory scientists, working with National Oceanic and Atmospheric Administration and university colleagues, have found that half of the global ocean heat content increase since 1865 has occurred over the past two decades.

“In recent decades the ocean has continued to warm substantially, and with time the warming signal is reaching deeper into the ocean,” said LLNL scientist Peter Gleckler, lead author of a paper published in the journal Nature Climate Change.

Changes in ocean heat storage are important because the ocean absorbs more than 90 percent of the Earth’s excess heat increase that is associated with global warming. The observed ocean and atmosphere warming is a result of continuing greenhouse gas emissions. Quantifying how much heat is accumulating in the Earth system is critical to improving the understanding of climate change already under way and to better assess how much more to expect in decades and centuries to come. It is vital to improving projections of how much and how fast the Earth will warm and seas rise in the future.

Increases in upper ocean temperatures since the 1970s are well documented and associated with greenhouse gas emissions. By including measurements from a 19th century oceanographic expedition and recent changes in the deeper ocean, the study indicates that half of the accumulated heat during the industrial era has occurred in recent decades, with about a third residing in the deeper oceans.

The team analyzed a diverse set of ocean temperature observations and a large suite of climate models. Scientists have measured ocean temperatures in a variety of ways over time, from lowering pairs of minimum-maximum thermometers to different depths on lines dangled overboard during the H.M.S. Challenger 1872-1876 expedition, to use of highly accurate modern instruments placed on robotic profiling floats (called Argo) that “phone home” the data using satellites, starting around 1999.

This study found that ocean warming estimates over a range of times and depths agree well with results from the latest generation of climate models, building confidence that the climate models are providing useful information. “The year-round, global distribution of ocean temperature data collected by Argo has been key in improving our estimates of ocean warming and assessing climate models,” notes LLNL oceanographer Paul Durack.

While Argo only samples the upper half of the ocean volume, pilot arrays of new “Deep Argo” floats that sample to the ocean floor are being deployed. This vast ocean volume in the deeper half is only measured infrequently by research vessels. Those deep data also show warming, even in the bottom layers of the ocean in recent decades. “Given the importance of the ocean warming signal for understanding our changing climate, it is high time to measure the global ocean systematically from the surface to the ocean floor,” said NOAA oceanographer Gregory Johnson.

Other authors include NOAA climate modeler Ronald Stouffer and Penn State Climate Scientist Chris Forest. The study was conducted as part of the Climate Research Program at Lawrence Livermore National Laboratory through the Program for Climate Model Diagnosis and Intercomparison, which is funded by the Department of Energy’s Regional and Global Climate Modeling Program. The NOAA contribution was supported by NOAA’s Office of Oceanic and Atmospheric Research. Work at Penn State was partially supported by the Department of Energy, Office of Science, Office of Biological and Environmental Research and by the National Science Foundation through the Network for Sustainable Climate Risk Management (SCRiM).

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Climate change: How do we know?

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See original article here.

The Earth’s climate has changed throughout history. Just in the last 650,000 years there have been seven cycles of glacial advance and retreat, with the abrupt end of the last ice age about 7,000 years ago marking the beginning of the modern climate era — and of human civilization. Most of these climate changes are attributed to very small variations in Earth’s orbit that change the amount of solar energy our planet receives.

Scientific evidence for warming of the climate system is unequivocal.
– Intergovernmental Panel on Climate Change

The current warming trend is of particular significance because most of it is extremely likely (greater than 95 percent probability) to be the result of human activity since the mid-20th century and proceeding at a rate that is unprecedented over decades to millennia.1

Earth-orbiting satellites and other technological advances have enabled scientists to see the big picture, collecting many different types of information about our planet and its climate on a global scale. This body of data, collected over many years, reveals the signals of a changing climate.

The heat-trapping nature of carbon dioxide and other gases was demonstrated in the mid-19th century.2 Their ability to affect the transfer of infrared energy through the atmosphere is the scientific basis of many instruments flown by NASA. There is no question that increased levels of greenhouse gases must cause the Earth to warm in response.

Ice cores drawn from Greenland, Antarctica, and tropical mountain glaciers show that the Earth’s climate responds to changes in greenhouse gas levels. Ancient evidence can also be found in tree rings, ocean sediments, coral reefs, and layers of sedimentary rocks. This ancient, or paleoclimate, evidence reveals that current warming is occurring roughly ten times faster than the average rate of ice-age-recovery warming.3

Here the article provides links to various types of evidence that are used to support the idea of climate change.

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The oceans are warming so fast, they keep breaking scientists’ charts

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NOAA once again has to rescale its ocean heat chart to capture 2014 ocean warming

Wow, was this a bad year for those who deny the reality and the significance of human-induced climate change. Of course, there were the recent flurry of reports that 2014 surface temperatures had hit their hottest values ever recorded. The 2014 record was first called on this blog in December and the final results were reported as well, here. All of this happened in a year that the denialists told us would not be very hot.

But those denialists are having a tough time now as they look around the planet for ANY evidence that climate change is not happening. The problem is, they’ve been striking out.

And just recently, perhaps the most important bit of information came out about 2014 – how much the Earth actually warmed. What we find is that the warming is so great, NOAA literally has to remake its graphs. Let me explain this a bit.

We tend to focus on the global temperature average which is the average of air temperatures near the ground (or at the sea surface). This past year, global air temperatures were record-breaking. But that isn’t the same as global warming. Global warming is properly viewed as the amount of heat contained within the Earth’s energy system. So, air temperatures may go up and down on any given year as energy moves to or from the air (primarily from the ocean). What we really want to know is, did the Earth’s energy go up or down?

The trick to answering this question is to measure the change in energy of the oceans. A thorough review of ocean heat measurement methods is found here; we paid the requisite fee to make the paper open access. Anyone can download and read it.

So what do the new data show? Well, it turns out that the energy stored within the ocean (which is 90% or more of the total “global warming” heat), increased significantly. A plot from NOAA is shown above. You can see that the last data point (the red curve), is, literally off the chart.

The folks at NOAA do a great job updating this graph every three months or so. We can now say that the 2014 Earth had more heat (thermal energy) than any year ever recorded by humans. We can also say that the folks at NOAA will likely have to rescale their graph to capture the new numbers. The NOAA site is updated by Dr. Tim Boyer and can be found here. Click on slide 2 to view the relevant image.

If people want to read a review of ocean heating that is written for a general audience, I suggest our recent peer-reviewed paper which can be found here.

So when we look back on 2014 and the records that fell, it gives us some pause about the so-called pause (hat-tip to Dr. Greg Laden for that phrase). Some people tried to tell us global warming had “paused”, that it ended in 1998, or that the past 15 years or so had not seen a change in the energy of the Earth. This ocean warming data is the clearest nail in that coffin. There never was a pause to global warming, there never was a halt, and the folks that tried to tell you there was were, well, I’ll let you decide. For me, the facts speak for themselves.

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Antarctic Bottom Water Warming and Freshening

Abstract

Freshening and warming of Antarctic Bottom Water (AABW) between the 1980s and 2000s are quantified, assessing the relative contributions of water-mass changes and isotherm heave. The analysis uses highly accurate, full-depth, ship-based, conductivity–temperature–depth measurements taken along repeated oceanographic sections around the Southern Ocean. Fresher varieties of AABW are present within the South Pacific and south Indian Oceans in the 2000s compared to the 1990s, with the strongest freshening in the newest waters adjacent to the Antarctic continental slope and rise indicating a recent shift in the salinity of AABW produced in this region. Bottom waters in the Weddell Sea exhibit significantly less water-mass freshening than those in the other two southern basins. However, a decrease in the volume of the coldest, deepest waters is observed throughout the entire Southern Ocean. This isotherm heave causes a salinification and warming on isobaths from the bottom up to the shallow potential temperature maximum. The water-mass freshening of AABW in the Indian and Pacific Ocean sectors is equivalent to a freshwater flux of 73 ± 26 Gt yr−1, roughly half of the estimated recent mass loss of the West Antarctic Ice Sheet. Isotherm heave integrated below 2000 m and south of 30°S equates to a net heat uptake of 34 ± 14 TW of excess energy entering the deep ocean from deep volume loss of AABW and 0.37 ± 0.15 mm yr−1 of sea level rise from associated thermal expansion.

When I tell people that ocean water is warming from the bottom up a common response that I get is:

“Do you mean that the hottest waters are at the bottom?”

This is a great illustration of the intellectual bankruptcy of atheism. Atheists can’t comprehend simple logic, and one of the ways that they cope with it is to instinctively warp whatever you said into something that they can understand. Since atheists automatically assume that everyone who disagrees with them is idiotic, they intentionally misinterpret whatever you said into something idiotic.

My response is simple enough:

Water warms at the bottom, as this happens the water is displaced upward by colder water.

The article appears to confirm this. Bottom water is freshening because of an influx of water from melting polar ice. This is also driving ocean circulation.

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Not only are ocean surface waters getting warmer, but so is water 1,500 feet below the surface.

This is a direct copy of a SciPop or news article preserved here because things on the internet have a bad habit of disappearing when you try to find them again. Full credit is given to the original authors and the source.

– Matty

Ocean Temperature

Warmer oceans put coastal communities at risk, increase infrastructure costs, endanger polar creatures and threaten coral reefs and fisheries. Perhaps most alarmingly, rising ocean temperatures accelerate the overall warming trend.

Continue reading “Not only are ocean surface waters getting warmer, but so is water 1,500 feet below the surface.”
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Surprising Depth to Global Warming’s Effects

This is a direct copy of a SciPop or news article preserved here because things on the internet have a bad habit of disappearing when you try to find them again. Full credit is given to the original authors and the source.

– Matty

Sarah Purkey is a Ph.D. student in the University of Washington’s School of Oceanography. Gregory Johnson is an oceanographer with the National Oceanic and Atmospheric Administration (NOAA) Pacific Marine Environmental Laboratory. They contributed this article to LiveScience’s Expert Voices: Op-Ed & Insights.

Introduction

The oceans are the flywheel of the climate system. As atmospheric concentrations of greenhouse gases increase, the Earth system is warming, and over 90 percent of that increase in heat goes into the ocean. Knowing how much heat the ocean absorbs is vital to understanding sea level rise (the oceans expand as they warm), and predicting how much, and how fast, the atmosphere will warm.

Continue reading “Surprising Depth to Global Warming’s Effects”
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Bottom Water Warming in the North Pacific Ocean

This is a direct copy of a SciPop or news article preserved here because things on the internet have a bad habit of disappearing when you try to find them again. Full credit is given to the original authors and the source.

– Matty

Abstract

Observations of changes in the properties of ocean waters have been restricted to surface1 or intermediate-depth waters2,3, because the detection of change in bottom water is extremely difficult owing to the small magnitude of the expected signals. Nevertheless, temporal changes in the properties of such deep waters across an ocean basin are of particular interest, as they can be used to constrain the transport of water at the bottom of the ocean and to detect changes in the global thermohaline circulation. Here we present a comparison of a trans-Pacific survey completed in 1985 (refs 4, 5) and its repetition in 1999 (ref. 6). We find that the deepest waters of the North Pacific Ocean have warmed significantly across the entire width of the ocean basin. Our observations imply that changes in water properties are now detectable in water masses that have long been insulated from heat exchange with the atmosphere.

Continue reading “Bottom Water Warming in the North Pacific Ocean”