Climate Change Part 3
So Far we learn how earth reacts with time she is capable to go through changes as it is natural and more changes to come some may be different some may be the same species born and die we are not the first ones no the last.
How Earth’s Climate Changes Naturally
Earth has been a snowball and a hothouse at different times in its past. So if the climate changed before humans, how can we be sure we’re responsible for the dramatic warming that’s happening today?
In part it’s because we can clearly show the causal link (opens a new tab) between carbon dioxide emissions from human activity and the 1.28 degree Celsius (opens a new tab) (and rising) global temperature increase since preindustrial times. Carbon dioxide molecules absorb infrared radiation, so with more of them in the atmosphere, they trap more of the heat radiating off the planet’s surface below.
But paleoclimatologists have also made great strides in understanding the processes that drove climate change in Earth’s past. Here’s a primer on 10 ways climate varies naturally, and how each compares with what’s happening now.
Solar Cycles
Magnitude: 0.1 to 0.3 degrees Celsius of cooling
Time frame: 30- to 160-year downturns in solar activity separated by centuries
Every 11 years, the sun’s magnetic field flips, driving an 11-year cycle of solar brightening and dimming. But the variation is small and has a negligible impact on Earth’s climate.
More significant are “grand solar minima,” decades-long periods of reduced solar activity that have occurred 25 times in the last 11,000 years (opens a new tab). A recent example, the Maunder minimum, which occurred between 1645 and 1715, saw solar energy drop by 0.04% to 0.08% (opens a new tab) below the modern average.
Scientists long thought the Maunder minimum might have caused the “Little Ice Age,” a cool period from the 15th to the 19th century; they’ve since shown it was too small and occurred at the wrong time (opens a new tab) to explain the cooling, which probably had more to do with volcanic activity.
The sun has been dimming slightly for the last half-century (opens a new tab) while the Earth heats up, so global warming cannot be blamed on the sun.
Volcanic Sulfur
Magnitude: Approximately 0.6 to 2 degrees Celsius of cooling
Time frame: 1 to 20 years
In the year 539 or 540 A.D., the Ilopango volcano (opens a new tab) in El Salvador exploded so violently that its eruption plume reached high into the stratosphere. Cold summers, drought, famine and plague devastated societies around the world.
Eruptions like Ilopango’s inject the stratosphere with reflective droplets of sulfuric acid that screen sunlight, cooling the climate. Sea ice can increase as a result, reflecting more sunlight back to space and thereby amplifying and prolonging the global cooling.
Ilopango triggered a roughly 2 degree Celsius drop that lasted 20 years. More recently, the eruption of Pinatubo (opens a new tab) in the Philippines in 1991 cooled the global climate by 0.6 degrees Celsius for 15 months.
Volcanic sulfur in the stratosphere can be disruptive, but in the grand scale of Earth’s history it’s tiny and temporary.
Carbon Dioxide and the Weathering Thermostat
Magnitude: Counteracts other changes
Time frame: 100,000 years or longer
The main control knob (opens a new tab) for Earth’s climate through deep time has been the level of carbon dioxide in the atmosphere, since carbon dioxide is a long-lasting greenhouse gas (opens a new tab) that blocks heat that tries to rise off the planet.
Volcanoes, metamorphic rocks and the oxidization of carbon in eroded sediments all emit carbon dioxide into the sky, while chemical reactions with silicate minerals remove carbon dioxide and bury it as limestone. The balance between these processes (opens a new tab) works as a thermostat, because when the climate warms, chemical reactions become more efficient at removing carbon dioxide, putting a brake on the warming. When the climate cools, reactions become less efficient, easing the cooling. Consequently, over the very long term, Earth’s climate has remained relatively stable, providing a habitable environment. In particular, average carbon
dioxide levels have declined steadily (opens a new tab) in response to solar brightening.
However, the weathering thermostat takes hundreds of thousands of years to react to changes in atmospheric carbon dioxide. Earth’s oceans can act somewhat faster to absorb and remove excess carbon, but even that takes millennia and can be overwhelmed, leading to ocean acidification (opens a new tab). Each year, the burning of fossil fuels emits about 100 times more carbon dioxide (opens a new tab) than volcanoes emit (opens a new tab) — too much too fast for oceans and weathering to neutralize it, which is why our climate is warming and our oceans are acidifying.
Plate Tectonics
Magnitude: Roughly 30 degrees Celsius over the past 500 million years
Time frame: Millions of years
The rearrangement of land masses on Earth’s crust can slowly shift the weathering thermostat to a new setting.
The planet has generally been cooling for the last 50 million years or so, as plate tectonic collisions thrust up chemically reactive rock (opens a new tab) like basalt and volcanic ash in the warm, wet tropics, increasing the rate of reactions that draw carbon dioxide from the sky. Additionally, over the last 20 million years, the building of the Himalayas, Andes, Alps and other mountains has more than doubled erosion rates (opens a new tab), boosting weathering. Another contributor to the cooling trend was the drifting apart of South America and Tasmania from Antarctica 35.7 million years ago, which initiated a new ocean current around Antarctica (opens a new tab). This invigorated ocean circulation (opens a new tab) and carbon dioxide–consuming plankton; Antarctica’s ice sheets subsequently grew substantially.
Asteroid Impacts
Magnitude: Approximately 20 degrees Celsius of cooling followed by 5 degrees Celsius of warming (Chicxulub)
Time frame: Centuries of cooling, 100,000 years of warming (Chicxulub)
The Earth Impact Database (opens a new tab) recognizes 190 craters with confirmed impact on Earth so far. None had any discernable effect (opens a new tab) on Earth’s climate except for the Chicxulub impact, which vaporized part of Mexico 66 million years ago, killing off the dinosaurs. Computer modeling suggests that Chicxulub blasted enough dust and sulfur into the upper atmosphere to dim sunlight and cool Earth by more than 20 degrees Celsius (opens a new tab), while also acidifying the oceans.
The planet took centuries to return to its pre-impact temperature, only to warm by a further 5 degrees Celsius, due to carbon dioxide in the atmosphere from vaporized Mexican limestone.
Asteroid Plus Killed Dinosaurs
The huge asteroid that hit Earth and wiped out the dinosaurs 66 million years ago was not alone, scientists have confirmed.
A second, smaller space rock smashed into the sea off the coast of West Africa creating a large crater during the same era.
It would have been a “catastrophic event”, the scientists say, causing a tsunami at least 800m high to tear across the Atlantic ocean.
Dr Uisdean Nicholson from Heriot-Watt University first found the Nadir crater in 2022, but a cloud of uncertainty hung over how it was really formed.
Now Dr Nicholson and his colleagues are sure that the 9km depression was caused by an asteroid hurtling into the seabed.
They cannot date the event exactly, or say whether it came before or after the asteroid which left the 180km-wide Chicxulub crater in Mexico. That one ended the reign of the dinosaurs.
But they say the smaller rock also came at the end of the Cretaceous period when they went extinct. As it crashed into Earth’s atmosphere, it would have formed a fireball.
“Imagine the asteroid was hitting Glasgow and you’re in Edinburgh, around 50 km away. The fireball would be about 24 times the size of the Sun in the sky – enough to set trees and plants on fire in Edinburgh,” Dr Nicholson says.
An extremely loud air blast would have followed, before seismic shaking about the size of a magnitude 7 earthquake.
Huge amounts of water probably left the seabed, and later cascaded back down creating unique imprints on the floor.
It is unusual for such large asteroids to crash out of our solar system on course for our planet within a short time of each other.
But the researchers don’t know why two hit Earth close together.
The asteroid that created the Nadir crater measured around 450-500m wide, and scientists think it hit Earth at about 72,000km/h.
The nearest humans have come to this scale of event was the Tunguska event in 1908 when a 50-metre asteroid exploded in the skies above Siberia.
The Nadir asteroid was about the size of Bennu, which is currently the most hazardous object orbiting near Earth.
Scientists say the most probable date that Bennu could hit Earth is 24 September 2182, according to Nasa. But it is still just a probability of 1 in 2,700.
There has never been an asteroid impact of this size in human history, and scientists normally have to study eroded craters on Earth or images of craters on other planets.
To further understand the Nadir crater, Dr Nicholson and team analysed high-resolution 3D data from a geophysical company called TGS.
Most craters are eroded but this one was well-preserved, meaning the scientists could look further into the rock levels.
“This is the first time that we’ve ever been able to see inside an impact crater like this – it’s really exciting,” says Dr Nicholson, adding there are just 20 marine craters in the world but none have been studied in detail like this.
Short-Term Climate Fluctuations
Magnitude: Up to 0.15 degrees Celsius
Time frame: 2 to 7 years
On top of seasonal weather patterns, there are other short-term cycles that affect rainfall and temperature. The most significant, the El Niño–Southern Oscillation, involves circulation changes in the tropical Pacific Ocean on a time frame of two to seven years that strongly influence rainfall in North America.
The North Atlantic Oscillation and the Indian Ocean Dipole also produce strong regional effects. Both of these interact with the El Niño–Southern Oscillation.
The interconnections between these cycles used to make it hard to show that human-caused climate change was statistically significant and not just another lurch of natural variability. But anthropogenic climate change has since gone well beyond natural variability (opens a new tab) in weather and seasonal temperatures.
The U.S. National Climate Assessment in 2017 (opens a new tab) concluded that there’s “no convincing evidence for natural cycles in the observational record that could explain the observed changes in climate.”
Orbital Wobbles
Magnitude: Approximately 6 degrees Celsius in the last 100,000-year cycle; varies through geological time
Time frame: Regular, overlapping cycles of 23,000, 41,000, 100,000, 405,000 and 2,400,000 years
Earth’s orbit wobbles as the sun, the moon and other planets change their relative positions (opens a new tab). These cyclical wobbles, called Milankovitch cycles (opens a new tab), cause the amount of sunlight to vary at middle latitudes by up to 25% and cause the climate to oscillate.
These cycles have operated throughout time, yielding the alternating layers of sediment you see in cliffs and road cuts.
During the Pleistocene epoch, which ended about 11,700 years ago, Milankovitch cycles sent the planet in and out of ice ages. When Earth’s orbit made northern summers warmer than average, vast ice sheets across North America, Europe and Asia melted; when the orbit cooled northern summers, those ice sheets grew again.
Since warmer oceans dissolve less carbon dioxide, atmospheric carbon dioxide levels rose and fell in concert with these orbital wobbles, amplifying their effects.
Today Earth is approaching another minimum of northern sunlight, so without human carbon dioxide emissions we would be heading into another ice age within the next 1,500 years or so (opens a new tab).
Faint Young Sun
Magnitude: No net temperature effect
Time frame: Constant
Though the sun’s brightness fluctuates on shorter timescales, it brightens overall (opens a new tab) by 0.009% per million years, and it has brightened by 48% (opens a new tab) since the birth of the solar system 4.5 billion years ago.
Scientists reason that the faintness of the young sun should have meant that Earth remained frozen solid for the first half of its existence (opens a new tab). But, paradoxically, geologists have found 3.4-billion-year-old rocks (opens a new tab) that formed in wave-agitated water. Earth’s unexpectedly warm early climate is probably explained by some combination (opens a new tab) of less land erosion (opens a new tab), clearer skies, a shorter day (opens a new tab) and a peculiar atmospheric composition (opens a new tab) before Earth had an oxygen-rich atmosphere.
Clement conditions in the second half of Earth’s existence, despite a brightening sun, do not create a paradox: Earth’s weathering thermostat counteracts the effects of the extra sunlight, stabilizing Earth’s temperature (see next section).
Evolutionary Changes
Magnitude: Depends on event; about 5 degrees Celsius cooling in late Ordovician (445 million years ago)
Time frame: Millions of years
Occasionally, the evolution of new kinds of life has reset Earth’s thermostat. Photosynthetic cyanobacteria that arose some 3 billion years ago, for instance, began terraforming the planet by emitting oxygen. As they proliferated, oxygen eventually rose in the atmosphere 2.4 billion years ago while methane and carbon dioxide levels plummeted This plunged Earth into a series of “snowball” climates (opens a new tab) for 200 million years. The evolution of ocean life larger than microbes initiated another series of snowball climates
717 million years ago — in this case, it was because the organisms began raining detritus into the deep ocean, exporting carbon from the atmosphere into the abyss and ultimately burying it.
When the earliest land plants evolved about 230 million years later in the Ordovician period, they began forming the terrestrial biosphere, burying carbon on continents and extracting land nutrients that washed into the oceans, boosting life there, too. These changes probably triggered the ice age that began about 445 million years ago. Later, in the Devonian period, the evolution of trees further reduced carbon dioxide ) and temperatures, conspiring with mountain building to usher in the Paleozoic ice age
Large Igneous Provinces
Magnitude: Around 3 to 9 degrees Celsius of warming
Time frame: Hundreds of thousands of years
Continent-scale floods of lava and underground magma called large igneous provinces have ushered in many of Earth’s mass extinctions. These igneous events unleashed an arsenal of killers (including acid rain, acid fog, mercury poisoning and destruction of the ozone layer , while also warming the planet by dumping huge quantities of methane and carbon dioxide into the atmosphere more quickly than the weathering thermostat could handle.
In the end-Permian event 252 million years ago, which wiped out 81% of marine species underground magma ignited Siberian coal, drove up atmospheric carbon dioxide to 8,000 parts per million and raised the temperature by between 5 and 9 degrees Celsius .
The more minor Paleocene-Eocene Thermal Maximum event 56 million years ago cooked methane in North Atlantic oil deposits and funneled it into the sky, warming the planet by 5 degrees Celsius and acidifying the ocean; alligators and palms subsequently thrived on Arctic shores.
Similar releases of fossil carbon deposits happened in the end-Triassic and the early Jurassic (global warming, ocean dead zones and ocean acidification resulted.
As a team of researchers studying the end-Triassic event wrote in April in Nature Communications, “Our estimates suggest that the amount of CO2 that each … magmatic pulse injected into the end-Triassic atmosphere is comparable to the amount of anthropogenic emissions projected for the 21st century.”
Why dinosars got destroyed but Mammals lived?
The short of it is, when mass extinction events happen the animals which are the most generalized and of smaller energy requirements tend to make it.
What that means is animals which can eat a wide variety of foods and aren’t dependent on just a few, and they don’t require a large number of calories to complete their life cycle.
Optimally this means smaller animals which grow up quickly, have a lot of babies, don’t need much energy, and can survive off a variety of foods.
This is why turtles barely even got affected by the mass extinction event at the end of the Cretaceous, because smaller turtles mature relatively quickly, have dozens of eggs per clutch (so even if only 10% survive, that’s still more than enough to replace the parents), and being cold blooded means they don’t need to eat all that much and when they do eat many species of turtles are omnivores which can subsist on a variety of foods.
Non-Avian dinosaurs had the worst combination and got hit at the worst possible time. They were relatively large bodied (yes, plenty were smaller, but talking on average here), more or less were warm-blooded (or close to it for some) and thus needed lots more energy than a cold blooded animal of equal size, and many matured relatively slowly. And being purely terrestrial for the most part meant that they couldn’t migrate to new areas as easily should their ecosystem get disrupted.
And the End-Cretaceous was a time the temperature was up and ocean levels got higher, cutting off many continents from each other. This means if the habitat of dinosaurs in North America changed but they could still survive in, say, Asia, they couldn’t reach there because a land bridge connecting the two just a few million years prior was now flooded.
The reason birds were the only dinosaurs to make it were because they were small (less energy needs), matured pretty quickly, beaked mouths meant they could exploit a variety of foods relatively easily, and flight meant they could migrate to try and take their chances somewhere else.
For comparison a T.rex would take about 14–16 years to reach full size and probably was only capable of reproducing by age 10 to 12 at the youngest.
A Great Blue Heron, a relatively big bird alive today, is more or less fully grown and sexually mature in 9 months to a year. Many small mammals can become fully mature in less than a few months.
Humans and Plastic
we are full of hypocricy, we shout and scream abot clomate change we pay high bills for the change and politicians spread moral panic and fear and what do we do? nothing we use plastic in our daily life those who shout they even use it more they destroy the planet. The working class can not afford private jets and luxurys all distribute to climate change. Those rich basteards kill the planet and force the poor to pay more taxes and high bills . YThose who claim to be prince or duchess they kill the planet in every move they do yet they go around and preach about climate change hypocrites liars you deserve the finger and much more.
Earth tolerated a lot of disasters I am not saying we are doing good but we are not doing bad unless we are all together in this we may see change if not middle finger up to earth.