Earth's sea ice hits all-time low, NASA satellites reveal

[Admin]

Sea ice impacts storms and coastal erosion — and NASA says Earth's total sea ice content has hit an all-time low.

Earth's sea ice hits all-time low, NASA satellites reveal : Read more

 

[Unclear Engineer]

While not trying to minimize the importance of the observed trend, I think that it is important to be careful of the context.

Statements about the ice level being at "an all-time low" and "the lowest Arctic winter sea ice levels have ever been" are not actually true. They are only the lowest levels that humans have recorded, during the geologically relatively brief period of our existence and ability to measure and record such things.

More objectively scientific statements would be something like "Sea ice levels are at the lowest levels ever recorded since humans began recoding them [fill in the blank] years ago." So, first, please fill in the number of years over which comparable records exist.

And, it is also important to place the number into the natural context of how the sea ice is at least thought to have changed in the previous interglacial periods over the last few million years and what those levels are thought to have been before the latest glaciation cycles, maybe 10 million years ago.

That perspective is important for considerations about humans "ruining" the Earth's climate and maybe turning into another Venus.

The observed trend should also be put into the shorter term context of what this implies for more immediate consequences for humans today. Sea ice formation and loss does not directly impact sea levels, because it is mostly frozen sea water. So, the relationship between sea ice extent and sea level needs to come from models of global climate, which have pretty large uncertainties for conditions not very far into the future. Still, saying that the observed loss of sea ice seems most consistent with some particular model's outputs that also predict a particular amount of sea level rise by 2050 or 2100 would provide some useful context.

 

[Ken Fabian]

Another record level of change as a result of anthropogenic global warming has been broken, yet people object to reporting on it that suggests it means global warming is very serious - objecting to the (repeated) breaking of such records being used to promote the cause of taking it seriously and addressing the causes.

What materially matters isn't how sea ice levels compare to millions of years ago when there was no homo sapiens but how it compares to the global temperatures and unusually stable climate regime (The Holocene) that allowed agriculture and civilisations to develop - compared to what has been disrupted and how that will affect people for whom we owe duties of care, starting with those now living, ie most especially the next century.

 

[Classical Motion]

I’m guessing that a sea ice level(area and depth) would depend on the number of data points(locations) and the accuracy of them.

I’m also guessing these data points are in a state of change and improvement. Adding more points and accuracy. Over the years.

So, how valid are the comparison sets? What’s the true duration of valid comparisons? 30-40 years perhaps. Since satellite. And then we have satellite improvement. More precision.

So what kind of a trend do we really have? I don’t think we have enough measured oscillations to tell very much. How much of that little trend is a measurement trend?

But I know nothing of it. Just thinking about the faith and prediction of such short time dependable data. On arctic ice levels. There is no climate record of it.

 

[Unclear Engineer]

Just photographic imagery can show that the areal extent of sea ice is far less than in the past.

Trying to get quantitative about it from a climate modeling perspective requires more info, such as thickness. And, there needs to be a time series of measurements over each year, not just max and min of areal extent. The transfer of energy needs to be calculated in some detail to tune a model, and the heat of fusion for ice is a big deal for that.

So, I agree that the Earth is warming, and I think that humans have made multiple changes that lead toward that effect - not just CO2 emissions.

And, I think it is clear that a lot of human infrastructure along coasts is going to eventually get flooded.

But, I also think there is good geological evidence that would happen if humans were not affecting global temperatures and sea levels. The sea level at the last peak, during the previous interglacial period, was 25 feet higher than today, and there is no argument that humans played any part in that previous high sea level.

So, I think it is important to put what we are seeing now into the appropriate perspective - which is much different from the politicized perspectives being pushed by activists and politicians who cater to them.

The temperatures and the stability of Earth's sea level and climate over the last few thousand years are not the norm for the last few million years. We need to expect that to change, because it changed before in cyclic ways.

Whether it changes by a natural cycle of phenomena or by human induced phenomena, or a combination of both, we should not be expecting no changes. We need to plan now to accommodate those changes in the most cost-effective ways for all sorts of nations and societies, because we simply do not have the knowledge nor the mechanisms to stabilize Earth's climate to suit our desires.

The activists and politicians tend to hype the concept that we are going to change Earth's climate so much that humans, and perhaps all life, will become extinct - maybe even turning Earth into another Venus. But, that looks like major B.S. when the temperatures, CO2 levels, sea levels, etc. are compared to what we can see in the geological records. We can see that sea level was 325 feet lower than today just 25,000 years ago. And we can see that it was about 300 feet higher than today many millions of years ago. We can see that there have been temperate climates at the poles in the distant past.

So, the real issue is what is changing now, trending toward what future conditions, and how will that affect both humans and the other parts of the ecosystem that humans depend on - and are damaging by many other phenomena in addition to adding CO2 to the atmosphere. We are killing other species very rapidly by habitat destruction, over fishing, pollution with chemicals, etc. And, that includes the ocean species as well as the terrestrial species. We need to care about more of our effects than just CO2 emissions if we want to create and maintain the type of environment that we say we want.