The Lapse of Uriel:

1
The Lapse of Uriel Climate Change Through
Geologic Time
Will Straight, paleontologist Northern Virginia
Community College, Loudoun Campus
2
"Line in nature is not found Unit and universe
are round In vain produced, all rays return
Evil will bless, and ice will burn."
Ralph Waldo Emerson (Uriel, 1846)
3
Uriel may have been warning the heavenly host
about climate change. For at least the last
billion years, Earths climate has been
constantly fluctuating.
Four events, four scales Snowball Earth
Permian-Triassic Hothouse Late Paleocene
Thermal Maximum Younger Dryas Stadial
4
Ever the wild Time coind itself into calendar
months and days.
TRIASSIC HOTHOUSE
SNOWBALL EARTH
YOUNGER DRYAS
PALEOCENE THERMAL MAX
.
5
Snowball Earth was a catastrophic global
cooling that began 1.0 billion years ago.
At that time, North America was a significantly
smaller continent we call Laurentia.
6
Australia
Africa
Antarctica
By about 950 Ma (October 10), Laurentia formed
the core of the supercontinent Rodinia.
China and Asia
South America
Europe
south pole
7
As it moved southward across the pole, Rodinia
accumulated enough ice to lower Earths surface
temperature. Evidence shows that ice sheets
spread outward from the continent into the ocean.

8
With the resurgence of carbon uptake, CO2
declined again, ice thickened, and the process
repeated. Couplets of tillite and limestone are
common in Proterozoic rocks.
When the ice spread, the microbes died back,
allowing CO2 to increase global temperatures,
which melted the ice. When CO2 increased, the
microbes rebounded and started the cooling again.
The cooling occurred because microbes were
drawing CO2 from the atmosphere and burying it as
limestone, the other type of rock in these
deposits.
Deposits made during the Snowball event are
partly tillite, the dust and gravel churned up as
glaciers scrap across exposed land.
9
Snowball Earth lasted from 950 to 600 Ma (Oct 15
to Nov 14), with ice expanding as far as the
tropics.
10
Twice, at 740 and again at 650 Ma, ice may have
covered even the equator.
11
The Snowball event ended as the continents
forming Rodinia drifted apart and moved off the
south pole. As the continents moved toward
warmer latitudes, they could no longer retain a
thick sheet of ice.
12
Over the last 600 Ma, four periods of icy climate
have occurred these were neither as severe or as
long as the Snowball interval.
Chemical records in marine rocks indicate that
since the end of the Snowball Earth interval,
global climate has been anything but stable.
For every Icehouse interval there has been a
corresponding Hothouse interval. The most
intense Hothouse corresponds with the
Paleozoic-Mesozoic boundary and a crippling mass
extinction.
Paleozoic
Mesozoic
Cz
Line in nature is not found
500 400 300
200 100
0 Ma
13
By 260 Ma (December 11), drifting continents had
merged again, creating the supercontinent
Pangaea.
Pangaea straddled the equator, not the pole.
In vain produced, all rays return
14
Pangaea acted like a thermal blanket, trapping
mantle heat inside the crust. As the continental
crust heated, the whole landmass rose, triggering
a chain of disastrous side-effects.
Swamp plants were also pumping up the O2 content
of the atmosphere. By the end of the Permian,
oxygen levels may have reached 30, almost half
again as much as today.
The rapid spread of new types of land plants in
coastal swamps were taking up massive amounts of
atmospheric CO2 and burying it as peat.
swamp
reef
ice layer
15
As the land rose, these swamps drained, killing
the plants. The peat and dead plants burned, a
process which consumed O2 and released CO2.
swamp
reef
ice layer
16
The rising continent also exposed the outer
shelf. Sediments on the shelf hold a type of
water ice that contains enormous volumes of
methane gas. These methane hydrates melt when
the weight of the water over them decreases.
Rising land also exposed reefs and sea floor
ecosystems. Reduced by Pangaeas growth, these
ecosystems collapsed.
reef
ice layer
17
Methane, CH4, is about ten times more efficient
as a greenhouse gas than CO2, but very
short-lived. It has a nasty impact as it breaks
down, however
CH4 2O2 ? 2H2O CO2
Heat and loss of oxygen during the late Permian
killed some 95 of life on Earth.
18
By 230 Ma (December 14), Pangaea began to break
up. Land plants recovered and began drawing CO2
back down.
The lost life was replaced by many modern animal
lines, including dinosaurs, birds, and our own
ancestors.
Evil will bless
19
Pangaeas break-up was playing havoc with oceanic
circulation. Warm water on formerly cold
continental shelves melted the deep methane
hydrate ice.
The same playerscontinental configuration and
atmospheric gasescaused another Hothouse
interval during the early part of the Cenozoic
Era.
C.R.Scotese, Paleomap Project
20
A heat spike called the Late Paleocene Thermal
Maximum, lasting from 55.5 to 54.8 million years
ago (Dec. 27, 320 to 520 pm), began with an
abrupt release of gas from methane hydrate ice.
Paleogene
Neogene
LPTM
60 50 40
30 20 10
0 Ma
21
Methane hydrates are highly volatile. Hydrate
deposits can release enormous volumes of methane
very suddenly if the ice melts. Samples of
hydrates produce so much gas, they can be set on
fire.
and ice will burn
22
The climate excursion and fall in O2 caused a
sudden turnover among early mammals on land and a
cascade of extinctions among marine life.
As before, the climate rebounded as plant and
animal life recovered and consumed the extra CO2.
23
Over the last half-million years, Earths climate
has cycled dramatically as part of the
Pleistocene Ice Age. We currently enjoy a
relatively warm interval.
These oscillations are related to orbital
dynamics of the Earth, but the response is again
in atmospheric gas balance, particularly CO2.
600 500 400
300 200 100 0 Ka
24
As the climate has cycled, glaciation has waxed
and waned in the northern hemisphere.
During the Younger Dryas, a brief cold snap 12000
years ago, humans used the ice as a bridge into
North America for the first time.
25
Heres the last 30 years change, on the same
scale.
Each warm interval began abruptly, but cooling
took time. This may be a response to methane
release (abrupt) and CO2 consumption (slow).
The Ice Age is over.
600 500 400
300 200 100 0 Ka
26
On the grander scale, however, this is still a
small change. Our planet itself has created hot
and cold intervals many orders of magnitude
worse. And life has survived every cycle.
Paleozoic
Mesozoic
Cz
500 400 300
200 100
0 Ma
27
Earth is in a constant state of change. It is
still changing. Before we can effect a rescue,
we need to know what part of this change is us,
and what part is natural. Trying to fix what we
dont fully understand risks further damage.
Archangel Uriel from Dionisius, Church of
Nativity of Virgin Mary
28
Conservation, not Correction Recycle, not Repair
And, shrilling from the solar course, Or from
fruit of chemic force, Procession of a soul in
matter, Or the speeding change of water, A
blush tinged the upper sky, And the gods shook,
they knew not why.
Archangel Uriel from Dionisius, Church of
Nativity of Virgin Mary