CLIMATE CHANGE and the MILANKOVITCH CYCLES

Many people outright deny the global climate is changing or that humans could possibly influence the climate.  They further argue that whatever changes are taking place are due to natural cycles although they never explain what those are.  Well, here is the explanation.

Climate change is a long term event that occurs in three predictable cycles as the earth orbits around the sun: Tilt (41k years), precession (19k to 24k years), and eccentricity (100k to 413k years).  They are known as the Milankovitch Cycles after the Serbian astronomer and mathematician who first calculated their magnitude in the 1920's.  The cycles change the climate by altering the amount of solar radiation that reaches the earth.

The tilt of the earth accounts for the changing seasons: winter, spring, summer and fall. The reason is the axis of the earth is at a different angle than the axis of the sun. Consequently, as the earth orbits around the sun the North Pole is inclined away from the sun in the winter and toward the sun in the summer. The South Pole is just the opposite.

The four seasons.

However, the tilt is not fixed and it cycles between 21.5 to 24.5 degrees over a span of 41,000 years. When the tilt is greatest, at 24.5 degrees, whichever pole is facing the sun will be warmer than usual in the summer and the opposite pole will be colder at the same time. This fluctuation causes the polar ice caps to expand and shrink accordingly.

The second cycle is precession which takes 21,000 years. It is a wobble to the tilt of the earth like the motion of the gyroscope below. The wobble increases the tilt and also effects the temperature of the earth and consequently the size of the polar ice caps. 

Precession

The last cycle is eccentricity which is an oscillation in the shape of the orbit of the earth around the sun.  Sometimes the earths orbit is near circular but over a period of 100,000 years the orbit flattens and lengthens.  Since the sun is not in the center of that orbit the planet is further away from the sun more of the time.  In the example given below the position of the sun is greatly exaggerated but it illustrates the idea.

Eccentricity

When the eccentricity is at its greatest the earth is closer to the sun during perihelion (91.4 million miles) and 3.1 million miles further away when at aphelion (94.5 million miles).   

Not to scale.

Individually and collectively the Milankovitch cycles are responsible for fluctuations in the amount of solar radiation that reaches the earth. Of the three cycles eccentricity has the greatest effect on the climate and is the cause of many global warming and cooling events in the past. A study of ocean sediments indicate ice ages have occurred approximately every 100,000 years for the last five million years. Currently the earth is moving toward aphelion and should be cooling off but it is not.

Global Warming is short term and refers to the human caused rise in the global temperature from greenhouses gases, primarily carbon dioxide. When fossil fuels such as coal or oil are burned carbon dioxide is released into the atmosphere. Like a greenhouse it traps heat from solar radiation and also heat from volcanism, forest fires, human industry and cities.  Since the industrial revolution started in 1763 the climate has been warming sporadically since 1880 and continually since 1980.

Global warming is not something contrived in just the last thirty years. In 1886 Savante Arrhenius, a Swedish physicist and chemist, was the first person to calculate human-induced global warming by carbon dioxide. He received the Nobel Price for chemistry in 1903. 

Guy Stewart Callendar, a British steam engineer and amateur climate scientist published a theory in 1938 that linked rising carbon dioxide concentrations in the atmosphere to global temperature. He thought it would be beneficial in delaying the return of the ice age. He was correct.

In the 1950's Callendar's claims provoked a few scientists to look at his work using better instruments and newer technologies that confirmed his conclusions. Their work was financed by the United States Military to determine if it could be useful in a war with Russia.

Al Gore, a member of the United States House of Representatives, held the first congressional hearings on climate change in 1976. In 2006 he presented and narrated the documentary film, "An Inconvenient Truth", which stirred global awareness but little response.

In 1988 NASA scientist James Hansen presented hard data to Congress that global warming was happening. Shortly afterward climatologists began informing the general public of the problem and its dangers, few people paid attention.  

To date 185 member countries of the United Nations have ratified the Paris Climate Agreement, a treaty to address global warming and to reduce emissions of greenhouse gases. Russia, the United States and ten other countries have not agreed to the treaty.

Climate change is a planetary cycle that normally takes place over one-hundred thousand years that would allow time for humans to adapt. Global warming is a symptom of climate change that shouldn't currently be happening that will create unnecessary human suffering and staggering economic cost in just a few hundred years.

An analogy from the National Aeronautical and Space Administration:  If  climate change was the flu,  global warming is its fever. 

Mark Thomas

BLACK BASIN AT SUNSET CRATER

Black Basin is a starkly beautiful sea of black cinders surrounded by cinder hills and volcanoes.  It is partly inside the Sunset Crater Volcano National Monument but most of it is outside the parks boundaries.  It's an area very few people ever visit. A barbed wire fence marks the park boundary and north of the fence hiking is permitted.  There are no signs and no trails but you can climb a cinder cone if you have the inclination. 

Sunset at Black Basin

The light, airy cinders are blown about by powerful winds racing down the leeward side of San Francisco Mountain.  Cinder waves several feet high collected in the basin forming the cinder sea pictured below.  Most of that area is protected behind a barbed wire fence to keep people from walking on it.   

A sea of cinder waves.

Two black parabolic cinder dunes are slowly creeping up the side of a very steep cinder hill I call Red Cone.  It may never reach the top as the wind is slowed and the source material stabilized by the slowly ever increasing vegetation.

A parabolic dune has nearly reached the top of Red Cone.

Parabolic Dunes

The black dune crest near the top of Red Cone. 

Snow hadn't fallen at Black Basin so on December 20th, 2016 I drove from Flagstaff to the base of Red Cone.  Starting at sunrise I made the 600 foot climb through the trees to the top of the mountain.  The scenery was spectacular in all directions and I'd say it's the best view of the eastern San Francisco Volcanic Field to be found.

The back side of Sunset Crater cinder cone to the south.

The San Francisco Peaks stratovolcano to the southwest.

O' Leary Peak volcanic dome and fire watch tower to the west.

Black Basin cinder hills to the northwest.

Strawberry Crater cinder cone and the Little Colorado
River Valley in the background to the northeast.

Black Mountain cinder cone to the northeast.  

I found a geocache  in a glass jar under a small rock cairn at the top of Red Cone. 

At the top of Red Cone there was a spot where limestone had extruded out of the ground.  Limestone pebbles litter the ground where a mammal dug out its borrow.  Limestone is a common constituent of many of the volcanoes in the San Francisco Volcanic Field.  There is a 350 foot thick layer of it under the entire area that is included in the mix as the volcanoes erupted.

   

Limestone extrusion.

White limestone pebbles dug out of an animal burrow.

The Cinder Hills Off Highway Vehicle play area and Merriam Crater were to the east but so was the sun so I couldn't take decent photos in that direction.

There is another worthwhile hike up to the cinder ridge separating the basin from Sunset Crater Park.  The natural earthen ramp on the side of Darton Dome makes for an easy route.  There isn't a trail but there is soil which is much easier to walk on.

The ramp is the row of large pine trees.

Some massive boulders litter the ramp and smaller rocks are scattered out on the cinder field.  Those rocks seem to be out of place to me.

Massive boulder on the ramp.

Boulder and cobbles on the cinder field.

I totally understand that the giant boulder on the ramp most likely rolled down the radically steep slope of Darton Dome, but I have a problem believing the rocks out on the cinder sea could roll so far from the mountain.  

The ramp itself is an odd feature too.  There a natural trough that runs between it and the  mountain side.  I think it likely that the ramp and rocks were deposited during the last ice age. 

During the Pleistocene epoch between 10,000 and 2.6 million years ago glaciers scoured the high mountains even in Arizona. I think it likely the ramp is a terminal moraine and the trough is a tarn but without the lake.  The rocks out in the cinder field were carried down by snow avalanches racing down the headwall and out onto the cinder field.

If you continue hiking up the ramp you will come to the cinder ridge.  Walk only on the crest of the ridge and not on the side facing Sunset Crater and the park.  The view of the Bonito Lava Flow and the San Francisco Peaks is astounding.

The cinder ridge.  In a shaded patch of snow I found bear tracks.

The Bonito Lava Flow and San Francisco Peaks.

Getting to Black Basin

Forest Service Road 546 (FS Rd 546) is exactly at the park boundary heading towards Wipatki Indian ruins. It is in good condition; however, it is a single lane road and if you pull off into the cinders you will get stuck. Take a four-wheel drive vehicle.

The east boundary sign.

It is 2.6 miles to the Wildlife Water Hole which is a big sheet of metal that channels water into a concrete cistern.  Park here.  There is a closed road on the left which leads to Black Basin in about half-a-mile. 

FS Rd 546

Go where you want from there but a barbed wire fence marks the national monument and you should not cross it.  Neither hike is long but climbing the red cinder cone is difficult.  It is 600 feet tall at an elevation of 7500 feet.

This place is too hot in the summer but late fall and in the spring it is ideal if there isn't to much snow.  It melts quickly on the black cinders but deep drifts can linger in the shady spots and block the road.

Note:  You won't find the name Black Basin on any map and the forest rangers at Sunset Crater won't know about it by that name either.  It is a name I gave to it because it is... black you know.

Black Mountain. It looks like a zebra.

Sometime in the early 1980's a powerful storm dropped about a foot of snow in Black Basin.  A friend and I cross country skied from the highway, climbed 800 feet up Black Mountain and skied back down.  It was quite a treat.

Alpine glow on the cinder hills separating the park from Black Basin.

Snow blows off the wave crests and fills the troughs between the waves.

Sunrise over Sunset Crater Volcano National Monument.

GLOBAL WARMING IN NORTHERN ARIZONA?

 Do you believe in global warming?

Increasingly violent and more frequent storms, floods, drought and fires are in the daily news.  These weather extremes are becoming the new normal and are attributed to global warming by the majority of scientists and governments throughout the world.  In spite of global opinion there are still people who do not believe in global warming.  Personally, I have witnessed the local climate getting warmer weather patterns changing in my lifetime.  

Photo taken towards Cameron on December 20th, 2016.  

AIR POLLUTION:  Strawberry Crater looking north.  The first line of cliffs are 30 miles away.  Navajo Mountain on the Arizona/Utah border is 115 miles away and barely visible.  Today there is a permanent haze in the atmosphere caused by vehicles, high altitude jets, industry and dust.  Visibility is now considered to be 10 miles when a century ago it used to be 100.  The only time the sky is clear is for about 24 hours following a significant rain or snow storm which is the best time for landscape photography. 

TORNADOES:  Tornadoes are rare in Northern Arizona but they do occur usually in the flat grasslands east of Flagstaff.    There are exceptions.  

On October 24th, 1992 one tornado touched down at Sunset Crater and knocked over a few Ponderosa Pine trees and damaged others.

On October 10th, 2010 six tornadoes were spotted west of Flagstaff at Bellemont.  At least three of them touched down and left swaths of destruction for up to 34 miles through the Coconino National Forest.   One EF3 tornado passed through Bellemont which derailed a train, destroyed the entire RV inventory of the Camping World dealership and damaged 30 homes.  That day 22 tornado warnings were issued by the National Weather Service for locations surrounding Flagstaff. 

Tens of thousands of trees were destroyed.

Twisted Ponderosa Pine tree.

30 homes  sustained significant damage. 

28 box cars derailed and damaged.

Camping World RV Dealership

Utility poles snapped off.

DROUGHT:   Northern Arizona has been in continual drought since 2002.  In some years significant amounts of rain or snow fell but overall precipitation was still below average.  The worst years were:

2002-2004, 2006-2007, 2010, 2012-2015 and 2018.

Drought is particularly devastating  because it carries such destructive secondary consequences.

BARK BEETLE:   The Bark Beetle outbreak that started in 2002 still continues today.  According to the United States Department of Agriculture between 2 and 3 percent of the  trees in Coconino National Forest have perished with up to 90 percent at localized sites. 

Bark Beetle Ponderosa Pine tree kill.

The only thing that can stop the bark beetle attack is rain and snow.  If the trees contain enough moisture  pitch will  drive the beetles out of their borrows underneath the bark.  This would require repeated years of above average precipitation which there is little hope for.

FIRE:   Fire is the most frequent hazard to occur in Coconino National Forest.  Since 1977 six mayor fires and dozens of  smaller ones burned areas of the forest.  Drought doesn't light fires but make them easier to start and to keep burning.  

1977 Radio Fire - Mt. Elden - 4,600 acres

1996 Hochderffer Hills Fire - NW of San Francisco Peaks - 16,680 acres

2000 Pumpkin Fire - Kendrick Peak - 14,760 acres

2006 Brins Mesa Fire - Wilson Mt to Slide Rock - 4,317 acres

2010 Schultz Fire - East side San Francisco Mountain - 15,075 acres

2014 Slide Fire - in Oak Creek Canyon -  21,000 acres

Slide Fire

The Slide Fire had progressed into Sterling Canyon just seven miles from our house and headed directly for us.  We were told to prepare to evacuate.  Two days later the fire was stopped at a fire-break six miles away. 

There was a 19 year separation between the 1977 Radio and 1996 Hochderffer fires suggesting conditions were wetter during the 70's and 80's.  I was actively hiking and backpacking in those decades and I don't recall any mention of drought during those years.      

1977 Radio Fire - Mt Elden............................................................... 4,600 acres
1996 Hochderffer Hills Fire - NW of San Francisco Peaks................16680 acres
2000 Pumpkin Fire - Kendrick Peak..................................................14760 acres
2006 Brins Mesa Fire - Wilson Mt and lower Oak Creek Canyon......4317 acres
2010 Schultz Fire - San Francisco Mountain.....................................15075 acres
2014 Slide fire - Upper Oak Creek Canyon and West Fork...............21000 acres
                                                                                         TOTAL......76,432 acres
                                                                                                            (120 sq. miles)

FLOODS:   There is one advantage to being in a drought; it means there is less chance of a flood.  Oak Creek has flooded many times almost always due to rain falling on a snow pack in the mountains.  Since 1993 the annual floods have generally gotten smaller and less frequent.  The largest flood in recorded history was in 1993 which reached a flow of 23,000 cubic feet per second (cfs).  There have been dozens of high water events over the decades but the five largest Oak Creek floods since 1982 were:

February,  1993     23,000 cfs
March,      1995     17,000 cfs
February,  2005     19,000 cfs
February,  2008     10,000 cfs
February,  2019     13,000 cfs 

Slide Rock, most likely 1993.

Rainbow Trout Farm below Indian Gardens,  2019

Lower Oak Creek,  2019

RAIN:  For as long as I can remember May and June where the two driest months of the year.  Then in 2017 significant precipitation fell during those months.  It wasn't heavy rains, just numerous small storms.  It had the odd effect of triggering all the Sycamore trees along Oak Creek to whither and drop their leaves like it was fall.  Over the rest of the summer the leaves then grew back again.

I contacted the Coconino National Forest botanist and he was unaware of it.  I later learned it was from a fungus that had formed on the leaves because of the timing of the rains.  This year we've had more than an inch of rain in May and the Sycamore trees are dropping their leaves, not as fast as in 2017 but it's happening again.    

SNOW:   In the 1980's when my children were young we took them out on Halloween for trick-or-treating.  Every year we would bundle them up because invariably there were a few inches of snow on the ground that had fallen in the last half of October.  That is not the case today.  The first measurable snowfall now falls in November if even then.

Also in the 1970's and 80's I was a cross-country and downhill skier.  The snow is not as reliable for these sports today. The ten year snowfall average in Flagstaff in 1980 was 110" per season.  By the year 2000 it had fallen to 90" and by the end of this decade it will be closer to 80".  (1980 and 2000 averages ascertained from National Oceanic and Atmospheric Administration data.)  

  

In January 60" of snow fell on our house in two days.

One of the exceptional storms.

We occasional have very heavy storms but they are the exception and the average precipitation is getting less. So is global warming real?  I definitely believe it is.