Arctic Sea Ice Not Doing Well

There has been a lot of news about the Arctic sea ice going around lately. None of it has been good. But, by now, that isn't a surprise. For those who haven't been keeping track, the tally on climate change news has been overwhelmingly in favor of the bad news variety.

A new study has come out that used an extensive amount of data from multiple sources. They used data collected by under-ice submarines, IceBridge plane flights, satellite data and even onsite measurements made by hand. Their research led to the conclusion the thickness of sea ice has decreased by 65% between 1975 and 2012. The specific number for September, when the ice is at its least extent, is even worse. They found the September thickness had decreased by 85% over that same time period. Not only has the extent decreased by 40% since 1980, but what is left is also 65% thinner. This means we can expect to see the rate of sea ice extent loss accelerate in the years to come. We can't be sure of the exact time table on that loss, but we can be sure it is coming.

With that in mind, I have to wonder what the data are telling us about the state of the ice right now. It appears there may be a serious problem with the ice extent.

This is a plot of the ice extent as reported by the National Snow and Ice Data Center (NSIDC):

Source: NSIDC

The dark, solid line is the 1981 - 2010 average ice extent for the year. The dark, dashed line is the ice extent for 2012, the year with the record low minimum extent, which occurs in September. The purplish colored line is the extent for 2006, the year with the lowest maximum extent, which occurs in March.  The blue line is the extent for this year. If you look closely, you can see the extent has been very close to a record low for the entire winter and now has turned lower. Instead of increasing extent, we are seeing decreasing extent. There are still about two weeks of ice growth season remaining, but this reduction in ice cannot be good. If we have actually passed maximum extent for the year, this would represent the smallest maximum extent ever recorded. And now, we find out it is also 65% thinner that it used to be.

In fact, the data indicate we may have already passed maximum ice extent for this year. Take a look at the ice temperature data from the Polar Portal:

Source: Polar Portal

I am not a fan of their selection for color distribution because it makes it difficult to judge the temperature accurately, but we can see the edge of the ice is already at, or above, the freezing point for water. That color extends well into the interior of the ice covered area. In other words, the ice is melting, not forming.

Take a look at one more graphic:

Source: Climate Reanalyzer

The light blue line indicates the average ice extent for this date. You can easily see just how much water area used to have ice this time of year and no longer does. In particular, look at the Gulf of Bothnia between Sweden and Finland. The blue line indicates it used to be completely frozen over. And, we're not talking about centuries ago. This is the 1979 - 2000 average. A mere three decades ago people were able to walk across that gulf, but not any more.

This data all leads me to believe we have already witnessed the sea ice maximum extent for this year. Like I said, there are still a couple of weeks to go in the season so I might be wrong. Hopefully, I am. Because if I'm right, the sea ice extent is not only much smaller this year, but it is also much thinner and we might be facing a bad melt season.

Stay tuned.

Greenland Mass Loss is Bad and Getting Worse

Greenland is melting, which is not good. Recent studies indicate it is even getting worse, too. Take a look at the mass of the Greenland Ice Sheet (GIS) and see what has been going on. This is plot of the GIS mass and comes from the Danish Polar Portal site:

Source: Polar Portal

This graph is of data obtained by the GRACE satellite and shows the change in mass due to the small change in the gravity field. It is easy to see the total mass of the the GIS is declining. The upticks in the graph show the mass is growing in the winter and the down ticks show the mass is declining in the summer. Hopefully, that is not a surprise nor should there be any controversy with that. But, what we see is that over a period of time the mass is decreasing more during the summer melt season than it is growing during the winter freeze season. As a result, the overall mass is decreasing on an annual basis.

But, there is something even more significant. Take a trend line for the period of about 2003 - 2009. Then, take another trend line for the period of 2010 - 2014. The second trend line is much steeper than the first. That means the rate of decline was much greater in the second period than in the first. Is the rate of decline accelerating? The data suggests it is and is something we will need to monitor. But, it gets worse.

A recent study used NASA laser altimeter data to study the entire surface of the ice sheet. That study found the estimate of mass loss was actually low and the amount lost during the 2003 - 2009 period amounted to 243 metric gigatons per year. This mass loss was enough that it contributed .68 millimeters of sea rise per year. During that one, seven-year period, Greenland melt water raised the oceans by about 5 millimeters (about .2 inches) all by itself. Projections are that melt water from the GIS will add about 9 inches (22 centimeters) to the sea level by the year 2100. That figure does not include melt water from Antarctica and glaciers.

Meanwhile, another study has been released that also indicates the melt rate is not going in our favor. The second study has to do with the melt ponds on the surface of the ice. As the ice melts in the summer, not all of it can flow away and it forms lakes on top of the ice. Sometimes, these lakes will refreeze when winter returns. Sometimes, the ice will crack and the water can flow into the interior of the ice sheet in a matter of a few hours. Either way, melt ponds are not good. Ponds are darker than ice and absorb more sunlight than the bright ice. The more ponds you have, the more heat gets absorbed, leading to more melting. If the water flows into the interior then it transports that heat into regions that would otherwise be insulated. That heat then gets trapped inside instead of being able to radiate into space. One scenario leads to more melting. The second scenario leads to a lot more melting.

The study released some interesting data. The melt ponds normally do not form outside of a band along the edge of the ice sheet. Away from the coast, it remains cold enough through most summers to prevent melt ponds from forming. But, that melt pond band has grown by 35 miles (56 kilometers) since the 1970s and is expected to have doubled by the middle of this century. Meaning, the melt rate will accelerate.

This changing nature of the melt ponds has not been included in projections, so the authors of this study believe the projections are low and we can expect to see even larger amounts of ice melt than we previously thought we would.

All in all, the data is not looking good for anyone in low-lying coastal areas. That's only a few billion people.

Once again, tell me how global warming is good for us.

Ocean Depths Not Getting Warmer

Scientists at the Jet Propulsion Laboratory have found that the deep oceans below 2000 meters have warmed little, if any, since 2005. This was a very neat study using in situ measurements as well as satellite data. What they did was to measure the increase in total ocean heat content and then subtract what has been measured in the top 2000 meters. What was left over was the amount of warming occurring in the oceans below 2000 meters and they found that it was small, if any.

I am not at all surprised by this result. I know that many people have been saying heat is being stored in the lower levels of the ocean, but my review of the literature did not lead me to that conclusion. There are many reasons, but the fact is that the majority of the deep ocean water originates in the polar areas. As sea water freezes it extrudes the salt, creating a briny soup which is heavier than the surrounding sea water and sinks. Nearly all deep ocean currents originate in the vicinity of Antarctica. For this reason alone, I would have been surprised that the deep ocean was warming. The ocean water around Antarctica is warming, but the briny water will still be nearly freezing because it originates from freezing water. Of course, it is much more complicated than that and there are many other factors involved, but this is the starting point. I just don't see any mechanism to transport heat from the upper-levels to the lower. It all has led me to the conclusion that I was not expecting to find much deep ocean heating.

Now, I know many contrarians are going to point at this study and claim that the oceans are not warming and that is NOT what this study says. What they found is that the DEEP ocean is not warming a perceptible amount. But, note that the only way you can get that result is by finding the upper levels are warming. The way they measured the lower heating is by taking the total heating and subtracting the known amount of upper-level heating. So, this result is only possible with the existence of that upper-level heating.

So, this is a very neat and important study. It does nothing to contradict anything we know about anthropogenic climate change, but it does illustrate we still have lots to learn - and that is not really news.