http://www.drroyspencer.com

The world continues to be very warm.

On 04/09/2019 11:55, wrote:
http://www.drroyspencer.com

The world continues to be very warm.


TV teletext news today had ref to this summer ice melt from Greenland
has been so great, that it has contributed an extra 1mm to global sea
level rise.
Of course Aviso.altimetry.fr has stopped updating to the public such
data since November last year, so perhaps just integrating the
melt-water data.


--
Monthly public talks on science topics, Hampshire , England
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On Wednesday, 4 September 2019 11:55:26 UTC+1, wrote:
http://www.drroyspencer.com

The world continues to be very warm.

It would not have been Teletext. The service ended after the digital switchover. BBC is the only channel that provides a text service known as BBC Red Button.

Nicholas
Meir Heath, Stoke-On-Trent 250 metres above sea level.

On 04/09/2019 19:42, Nicholas Randall wrote:
On Wednesday, 4 September 2019 11:55:26 UTC+1, wrote:
http://www.drroyspencer.com

The world continues to be very warm.

It would not have been Teletext. The service ended after the digital switchover. BBC is the only channel that provides a text service known as BBC Red Button.

Nicholas
Meir Heath, Stoke-On-Trent 250 metres above sea level.



https://www.bbc.co.uk/news/science-environment-49483580

Climate change: Greenland's ice faces melting 'death sentence'
By David Shukman Science editor

3 September 2019


Greenland ice loss

Greenland's massive ice sheet may have melted by a record amount this
year, scientists have warned.

During this year alone, it lost enough ice to raise the average global
sea level by more than a millimetre.

Researchers say they're "astounded" by the acceleration in melting and
fear for the future of cities on coasts around the world.

One glacier in southern Greenland has thinned by as much as 100 metres
since I last filmed on it back in 2004.
Why does Greenland matter?

Essentially because its ice sheet is seven times the area of the UK and
up to 2-3km thick in places. It stores so much frozen water that if the
whole thing melted, it would raise sea levels worldwide by up to 7m.

No one is suggesting that could happen for hundreds or even thousands of
years but even a small increase in the rate of melting in coming decades
could threaten millions of people living in low-lying areas.

Bangladesh, Florida, and eastern England are among many areas known to
be particularly vulnerable to rises in sea level over the course of the
century.

And although the island of Greenland is remote, stretching from the
north of the Atlantic high into the Arctic, its fate could have major
implications for the severity of future flooding and may even alter
coastlines and force communities to move inland.

The stark photo highlighting Greenland’s ice loss
Rain melts Greenland ice even in winter
Mighty Greenland glacier slams on brakes

One of the scientists studying the ice sheet, Dr Jason Box of the
Geological Survey of Denmark and Greenland (GEUS), says he's unnerved by
the potential dangers and that coastal planners need to "brace themselves".

"Now that I'm starting to understand more of the consequences, it's
actually keeping me awake at night because I realise the significance of
this place around the world and the livelihoods that are already
affected by sea level rise," he told me.
How much is Greenland melting?

Until recently, the ice sheet was generally in a state of balance - the
amount of snow falling in winter was roughly equal to the amount of ice
melting in summer.

Last year, there was actually a gain in ice but that was relatively
unusual. Over the last 30 years, decade-by-decade, Greenland has tended
to shed more ice.

Either the ice melts at the surface which sends torrents of water down
to the surrounding seas or huge chunks of ice break off from the margins
and float away as icebergs, gradually to melt.

Recent years have seen hundreds of billions of tonnes of ice lost - and
a rough guide to the effect on sea level is that 362 billion tonnes of
melt raises the average ocean level by a millimetre.

That doesn't sound a lot but in 2012 Greenland's loss totalled about 450
billion tonnes, and this year's melt is on course to produce about the
same, or even slightly more, with some researchers suggesting it could
raise sea levels by up to 2mm.

And on top of that you have to factor in the ice melting in Antarctica
plus the effect of water expanding as it warms. It all raises the level
of the oceans.

According to Dr Box, it's the recent increase in the average temperature
that's being felt in Greenland's ice: "Already effectively that's a
death sentence for the Greenland ice sheet because also going forward in
time we're expecting temperatures only to climb," he said.

"So, we're losing Greenland - it's really a question of how fast."
How rapidly is the ice sheet changing?

I've seen for myself what's happened to one corner of it. Sermilik
glacier at the southern end is not one of Greenland's largest but it
does rank as one of the fastest-shrinking streams of ice anywhere in the
world.

To reach it back in 2004, we flew past towering cliffs of ice, the front
of the glacier an immense wall of pale grey and blue standing high above
the sea.

At that time, we accompanied a scientist who checked instruments
positioned on the ice and he was stunned to see how the surface of the
glacier was dropping by as much as a metre every month.

And over the past 15 years, that rate of shrinking has continued so
aggressively that now, on a return visit to the same glacier, the ice
looks diminished, almost battered, and far less dominating in the landscape.

Jason Box is with me and he gathers the latest readings which show that
over this summer alone the glacier has shrunk by an estimated 9m.
"That's an astounding rate of loss," he said.

Since my last visit, the surface of this margin of the ice sheet has
lowered by an extraordinary 100m, more than halving in thickness,
exposing the remaining ice to the relatively warmer temperatures of
lower altitudes.
What's happening to the ice itself?

While you might think of the Arctic as a pristine white landscape, the
startling feature of the surface is how dirty it looks. Walking on it
feels like arriving on the Moon.

There are big areas of pale grey and smaller patches that are much
darker, covered with what appears to be mud or silt - it's a grim and
rather depressing sight.

It used to be thought that this darkness was mainly caused by a mix of
dust and pollution particles carried on the winds from distant power
stations and industrial centres.

But since my last visit to Sermilik glacier, scientists have made an
important breakthrough in understanding that a major cause of the
darkening is in fact biological - algae, microscopically small plants
that are flourishing in the melting ice.

By turning the surface grey, or black, from its usual bright white, the
algae make it less reflective, so it absorbs more of the Sun's rays.
This accelerates the warming and in turn leads to even more melting.
Who's trying to work out what's going on?

With the stakes so high for so many millions of people around the world,
Greenland is the target of a major international research effort
involving satellites, monitoring flights and expeditions on the ice itself.

The US space agency Nasa has for years run projects investigating
exactly what's causing the ice to melt and what could happen to it in
future.

Back in 2005, I reported on a Nasa-funded team that made an important
discovery about the movement of the ice sheet.

Although the great mass of ice looks immobile, it's actually always
inching down towards the coast and the team found that this movement
doubles in speed in summer - as mel****er from the surface works its way
to the bottom of the ice and helps it to slide along.

Another revelation is that the ice is not only being melted by the air,
as the atmosphere heats up, but also by warmer water reaching underneath
the fronts of the glaciers. One Nasa scientist describes the ice as
being under a hair-dryer and at the same time also on a cooker.

And Jason Box and his colleagues at GEUS run a network of sensors on the
ice to record details of the height of the surface and its reflectivity,
and how they're changing.

The hardest challenge for the scientific community is understanding
enough of the mechanisms of the ice sheet to be able to offer reliable
forecasts of sea level rise.

Dr Masashi Niwano, a researcher with the Japan Meteorological Agency, is
just back from a field trip to gather data to try to validate his
computer simulations of the ice.

"The ice sheet mass is decreasing - that is very certain. And these
results affect global sea-level rise - that is also very certain," he said.

.......


++++++++
Just because the TV text data is not in the VITS these days , its still
teletext to me.

--
Monthly public talks on science topics, Hampshire , England
http://diverse.4mg.com/scicaf.htm