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Climate climate change natural man made  causes and facts | Upload General

Climate Change Natural Man Made: Causes And Facts

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by: Sharai Hoekema
climate change natural man made  causes and facts | Upload

Climate Change Natural Man Made: Causes and Facts is the first article in a series of 6 on the topic of climate change.

There are many issues that should be discussed at the highest levels and at the water cooler alike. Although in a surprising twist, you might not know what the top-ranking global issue threatening our world is. The one issue that is more urgent and more pressing than all of those mentioned above. The one that threatens our very existence.

Recommended: Climate Agreement Paris And The Denial Of President Trump

Climate change! Already in 2013, before the Paris Climate Agreement became a 'thing', 56% of countries questioned in an international survey indicated that global climate change would be a major threat to their country. This number rose to 63% in 2017, before reaching 67% one year later, in 2018. 

Sign

Natural Man Made

This first article in my series on climate change will discuss what, exactly, climate change entails. It summarises and reflects the commonly accepted scientific consensus on the systems that make and influence our climate, describing the immense complexity. Just to be perfectly clear: this article is not meant to point the finger at anyone. It is not taking a side in the debate of man made versus natural occurrence.

The article is meant to explore the concept from the most objective standpoint possible. It will inevitably include words like ‘estimate’, ‘approximate’, ‘observed’, ‘hypotheses’, ‘models’ and ‘uncertainty’ - as those are the perfect representation of the complexity of the issue and the widely varying opinions on the topic. 

Words are playing an important part as it is, as they form such an important part of how individuals look at climate change and perceive it. We experience climate change using our specific set of constructs and references. People might speak of their observations on a local level, citing their climate-related life experiences. Farmers use terminology that distinguishes between great and not so great seasons, linking that season’s weather to the related harvest yield. Scientists look at longer periods of time and distinguish trends on a larger scale.

These perceptions all have one thing in common: they look at change. 

Climate Change! What Is It?

Let’s just dive right in with the most significant question - that has proven to be the most difficult to answer. In a nutshell, climate change occurs when certain changes in our earth’s climate system lead to new weather patterns that last for at least a number of decades, although they could just as easily last for millions of years. 

This definition is pretty much stone-clad, although it offers some definitions that are not as definitive. What does, after all, make up this climate system that is so determinant? Most will agree that our climate system is composed of five elements that interact with one another:

  • Atmosphere, or the air around us
  • Hydrosphere, or the water surrounding our continents
  • Cryosphere, or the ice and permafrost covering our poles
  • Biosphere, or all living things and beings
  • Lithosphere, or the surface soils, rocks and sediments

These elements rely on each other, which is why even subtle changes in one of them will have a big impact on the system as a whole. The system is ultimately powered by the sun, where it gets most of its energy from - with only a small portion taken from the earth’s interior. At the same time, the climate system ‘radiates’ energy as well, sending it off in outer space. 

This balance of incoming and outgoing energy, combined with the way it passes through our climate system, makes up our earth’s energy budget. If there’s more energy incoming, we say that the earth has a positive energy budget - meaning that the climate system as a whole is warming. On the other hand, if there’s a greater outflow of energy, we have a negative energy budget, letting the earth experience a period of cooling.

The incoming energy ‘flows’ through the climate system, being distributed around the globe by winds, ocean currents and other similar mechanisms. This results in what we know as the weather - as well as the long-term averages of weather, that we refer to as climate. Thus, it will not hold up if you refer to one bad summer as indicative of climate change - it will, though, if there are notable changes in the long term average. This, and only this, is what we refer to as climate change.



                                                   Scientist Explains Climate Change Using Maps | WIRED
                                                    Climate Change Natural Man Made: Causes And Facts

Climate Change: Man Made Or Natural

Unfortunately, for all intents and purposes, 'climate change' has become the catch-all phrase for a vastly divergent group of concepts - including being used as a technical description of the process at hand as well as a noun that is used to describe the problem. 

Recommended: Climate Change: Water Scarcity, Hunger, Agriculture And Food

Consequently, both the terms ‘global warming’ and ‘climate change’ are used interchangeably, now often being used to reflect man-made climate change (or global warming) in particular. This bias continues to exist even in popular scientific literature, making it harder to form a clear image of the actual problem.

In order to avoid any confusion, this series of articles will utilise the most commonly accepted definition of climate change: a change in the statistical proporties of the climate system when considered over long periods of time, regardless of cause. This excludes weather evens like El Niño, that represent fluctuations over periods shorter than a few decades.

Taking the explanation above into account, it will not be hard to see why these changes could partially result from the so-called ‘internal variability’, where the energy budget is altered by natural processes that make up our climate system, and partially by human activities.

NASA CO2 cycle
The carbon cycle, showing the movement of carbon between land, the atmosphere and the oceans. Yellow numbers are natural fluxes and red numbers are human contributions in gigatonnes of carbon per year. White numbers indicate stored carbon (The Carbon Cycle , NASA).

History Of Climate Change

When looking into the causes and historical trends for climate change as a whole, to better understand both natural processes and human influence, researchers usually focus on evidence as preserved in typical climate proxies such as ice cores, ancient tree rings, geologic records of changes in sea level and glacial geology.

3 men examen an ice cor
Photo by: B.A.S. Dr E.C. Pasteur removing an ice core from the core barrel during drilling on an ice dome on Berkner Island. The collaborative drilling programme with the Alfred-Wegener-Institut, Bremerhaven, Germany recovered ice cores to study the climate and atmospheric conditions of the Weddell Sea region over the past millenium.

These ‘time-capsules’ allow us to understand climate in a way we were unable to before. Before the 18th century, scientists were blissfully unaware of this thing called ‘climate’ and how earlier, prehistoric climates could be different from their own time period. Only towards the end of this century did they find evidence of changes in climate in geological ages long past, using the methods above.

Through paleoclimatology, we try to study the changes in climate taken on the scale of the entire history of earth. Historical climatology, on the other hand, studies historical changes in climate and maps out the effect that they have had on human history and development. This heavily relies on the written word, hidden in sagas, chronicles, maps and literature; as well as on paintings, drawings or rock art to form an adequate picture of the past.

It has been claimed that climate changes in the past are hiding in plain sight: driving changes in settlements and agricultural patterns, or even going so far as linking the rise and fall of various civilisations to significant climate events. Those have often been included in archaeological records, making it a silent witness (or perhaps even instigator) to many of the world’s biggest historical moments.

Tracing Climate Change’s Tracks

Today, far less ‘guessing work’ is involved. We have satellites circling the earth that capture the incoming and outflowing radiation, making it relatively easy to track our energy budget - and with that, a significant portion of climate change. Such technological advances have only made it easier for us to deepen our research in the phenomenon, helping us to understand the working of our climate system.

Graphic energy balance
The incoming and outflowing radiation

When looking specifically at proof supporting the current climate change, there are several ways to go - aside from data captured by these satellites. These include reports on extreme weather events, as well as temperature records and the disappearance of ice all around the world. These graphic and very physical pieces of evidence are chosen for their irrefutability and comprehensibility alike: no scientific background is needed to ‘understand’ the impact of ice caps collapsing before our very eyes.

Melting ice caps are actually not just used to sensationalise climate change. Glaciers are some of the most sensitive indicators of climate change. They are in many aspects representative of the world’s energy budget: with the size depending on the balance between snow input and melt output. Hence, warming temperatures will cause glaciers to retreat - unless enough snow is ‘inputted’ to balance it out.
Through a world glacier inventory, that also relies on satellites to track their size and location, scientists can get a clear picture of what is happening to this ‘glacier budget’ and, hence, with the world’s energy budget at large. And, spoiler alert, it hasn’t been looking good for the past decades, with significant shrinkages found all around the world.

Related with this subject is the Albedo effect. Albedo is a measure of the reflectivity of a surface. The albedo effect when applied to the Earth is a measure of how much of the Sun's energy is reflected back into space. Overall, the Earth's albedo has a cooling effect. (The term ‘albedo’ is derived from the Latin for ‘whiteness’).

Further evidence of climate change can be found in the Arctic sea. Mostly covered in sea ice, it has seen a major decline in both the extent and the thickness. Through satellite images, we have been able to establish that each decade, some 13.2% of sea ice is disappearing. 

Recommended: Waste In Space Will Be Fetched By The CubeSail Garbage Truck

Melting glaciers and sea ice are at the core of a whole other problem, being the rising of sea levels. This is another stable indicator of climate change’s progression, showing how the earth’s temperature correlates with sea levels. Through the dating of coral reefs, coastal sediments, marine terraces, limestones and nearshore archaeological remains, it is possible to establish the sea level for periods of which we roughly know the average global temperature.

Melting glacier

For instance, in the early Pliocene, global temperatures were some 1-2˚C warmer than they are today. Sea levels were also 15-25 meters higher than today, painting a relatively grim image for our future - especially for those living in coastal regions.

Other indicators of climate change that are used today are changes in ice cores, cloud cover and precipitation, vegetation, forests, pollen and animals. Modern techniques will stop at nothing to figure out how climate change has influenced any of these in the past and thus predict what our future might look like if global temperatures are to rise even further.

Climate Forcing Mechanisms

Through such historical and empirical research, several factors have been identified that pretty much ‘shape’ our climate as they are capable of influencing the energy budget, that frail balance determinant of climate. These are referred to as climate forcing or ‘forcing mechanisms’.

The way in which the five elements making up the climate system respond to such forcing mechanisms varies. This feedback can serve to amplify or diminish the initial ‘forcing’, either bringing along disruption or stabilisation of climate. Oceans and ice caps, for instance, are relatively slow in responding - whereas the atmosphere, biosphere and lithosphere can be much quicker to react. 

For all of these elements, there is a certain threshold factor. Up until reaching that threshold, not much change will be noted - but this will change quickly upon passing it, setting major and often irreversible changes in motion. Forcing mechanisms can be internal or external and lead to a slow or fast response of the climate system: a volcanic eruption will lead to a sudden cooling, while the warming of ocean water will have a much longer ‘time to impact’.

Internal Forcing Mechanisms

Internal forcing mechanisms are the natural processes that opponents of the man-made theory often point at as the main culprit. These occur within the climate system itself - within one of the five elements that I mentioned earlier, to be exact. Any natural changes in one or several of these five elements might lead to internal ‘climate variability’, or natural climate change. 

One example of such a forcing mechanism is a change in the type and distribution of species. Life, as it stands, affects climate through its role in the carbon and water cycles - or by triggering various other mechanisms such as: 

  • cloud formation, to reflect sunlight
  • evaporation and transpiration, from land and ocean surfaces to the atmosphere
  • and weathering, or the breaking down of rocks, soils, wood and minerals 

evaporation and transpiration, from ocean surfaces to the atmosphere

Evaporation and transpiration, from land and ocean surfaces to the atmosphere

In the past, several instances have been noted where life was ultimately decisive in changes to the climate. We are talking about millions or even billions of years ago, where vascular land-plants, marine phytoplankton, or grass-grazers have been acting as the main culprit.

Another example of an internal forcing mechanism is a change in ocean-atmosphere circulations. As it turns out, when the hydrosphere (oceans) and the atmosphere work together, pretty significant things can happen. Together, they can create spontaneous internal climate variabilities that can last for years - or even decades - on end. 

This includes El Niño and his sister La Niña, both of which cause a periodically repeated reversal of the direction of movement, as well as the lesser known Pacific decadal oscillation and the Atlantic multidecadal oscillation. All of these redistribute heat from the deep ocean to the atmosphere and/or alter the cloud/water vapor/sea ice distribution. This has a pretty profound impact on the earth’s energy budget.

External Forcing Mechanisms

External forcing mechanisms are those that are ‘out of the ordinary’, so not directly caused by the climate system itself. Even here, there might still be an element of natural causes - including changes in solar output, changes in the earth’s orbit, or volcanic eruptions. Some famous examples are the Milankovitch cycles or the Vostok ice core.

A first example of external forcing mechanisms, solar output, has been a notorious contributor to climate change for centuries. There have been some pretty significant variations in solar activity, based on observations of sunspots and beryllium isotopes. 

There was, for instance, a period of remarkably few sunspots in the late 17th century - the Maunder Minimum. And while some of those periods have been long term, others have been pretty short term. Either way, they have a big impact on global climate: the Maunder Minimum has been cited as one of the main triggers of the Little Ice Age that took place between 1550 and 1850 AD. 

The exact effect of solar variability on global temperatures has not yet been firmly established, with a 2010 study by CERN suggesting that ‘the effects of solar variability on temperature throughout the atmosphere may be contrary to current expectations.’ Working on a theory outlining aerosol formation in the lower atmosphere, it may very well be that these are (partially) driven by human activities as well. 

Milankovitch cycles
Milankovitch cycles

A second example of external forcing mechanisms are the orbital variations of our planet. Even the slightest variations in the motion of our earth will change how much sunlight reaches the earth’s surface in particular areas during particular seasons. Such kinematic changes can stem from the tilt angle of the earth’s axis of rotation, the precession of earth’s axis, and changes in the earth’s eccentricity. 

When you combine these three, so-called Milankovitch cycles are produced, that influence our climate to the extent that they have been linked to glacial and interglacial periods in the past, as well as the advance and retreat of the Sahara. Powerful effects of a relatively minor adjustment in our earth’s position.

Thirdly, volcanic activity and plate tectonics have been known to be climate-changers as well. Some eruptions, those injecting at least 100,000 tons of SO2 into the stratosphere, have had a significant impact on our climate. SO2 and sulfate aerosols are responsible for the creation of a sulphuric acid haze, capable of absorbing and scattering solar radiation before it reaches the surface. This leads to a cooling effect that can last for several years.

For instance, the eruption of Mount Pinatubo in 1991 lowered global temperatures by an average of 0.5 °C for three whole years. Earlier, the eruption of Mount Tambora in 1815 has been documented to have caused the ‘year without a summer’. Yet, for comparison’s sake, the impact of volcanic eruptions does not even come near the effect of human emissions: humans generate some 100-300 times the amount of carbon dioxide emitted by volcanoes. 

Anthropogenic Mechanisms

This leads to the next, obvious point. The majority of external forcing mechanisms are anthropogenic, or man-made. Most notably, it includes greenhouse gasses and dust particles in the atmosphere. The current scientific consensus is that our climate is changing in a largely irreversible manner, and that those changes are in part caused by human activities.

This is backed by a strong, credible body of evidence and runs through multiple lines of research. It is pointing at the increase in CO2 levels as the most concerning factor influencing climate change. Our earth’s atmosphere, commonly known as air, surrounds our planet and is one of the main players of the climate system. It should contain a large amount of nitrogen (78.09%), oxygen (20.95%), a small amount of argon (0.93%), and an even smaller amount of carbon dioxide (0.04%). 

Now that carbon dioxide in our atmosphere is rising steadily, it is not hard to see how this can cause a misbalance in the atmosphere, setting in motion a potentially disastrous sequence of global warming. This increase in emissions is largely, aprtly resulting from fossil fuel combustion, use of aerosols, and cement manufacturing. Although there are several other factors, including animal husbandry, deforestation and ozone depletion. All man-made or, at least, man-related issues.

The IPCC has stated that the human-caused change in our climate will impact both human and natural systems on all continents and across the oceans. A pretty definitive and clear statement that serves to remind us of the actual mechanism driving this particular wave of climate change that we are riding today. And, just in case it is not clear yet: this mechanism is partly us. 

Thankfully, we are also 'a' mechanism that could be used to avoid partly the worst consequence - if only we put our minds to it. The next article in this series will look at who is actually on board to take action and help us ride out this particularly worrisome climate wave.

Before you go!

Recommended: Five Minutes To Midnight: Climate Change Action Fighting The Clock

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Carlos Moreno - 20 WEEKS AGO
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Desde que en 1994 publiqué "La Bomba F y los Males del Planeta" sostengo que las emisiones de Gases Fluorados -sobre todo Fluoruro de Hidrfógeno, Perfluorocarbones... y ahora Fluoruro de Nitrógeno - son las responsables primeras de la destrucción de Ozono Estratosférico, y principales en cuanto a Efecto Invernadero. The Science Of Air Pharmacology or Chemtrails by Jim Phelps. Es ciencia y verdad... Blanqueen y Controlen las emisiones de FH, PFC y F3N ... será la verdad revelada.
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Mahinda Panapitiya - 20 WEEKS AGO
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Due to recent climatic changes taking place at global level, world is now heading for a disaster environmentally, unless some kind of a middle path is adapted in economic planning of future development projects. How to define a middle path in relation to economic development is a research need. Conventional Middle path is a person specific point of view and therefore the middle varies from person to person, from nation to nation and even politically within a nation. However the middle path meant in Buddhism for development is universal and common to all the living beings. Though the Buddhist middle path is conventionally explained in relation to spiritual development, material development focusing physical health is also stressed as a necessary pre-requisite for spiritual achievements. In order to understand this universally common middle path applicable to both spiritual and material development, design features of projects already implemented by the planners equipped with Buddhist Vision in its right spirit, could be used as an exploration ground. For an example, healthy food was the main objective of Ancient Irrigation Technology (AIT). Irrigation Projects which have been sustained more than 2000 years and still functioning in some parts of Sri Lanka, designed using the AIT, is the best entry point for that exploration. This is also a timely need because the projects developed during the last century using Modern Irrigation Technologies (MIT) have already failed due to reasons such as water pollution, human elephant conflicts and never ending dependency of farmers for fertilizer subsidies etc. In the proposed exploration, modern tools such as circular economic models would be used to analyse the reasons contributed to that long term sustainability. Recently made effort known as Water Quota to simulate outcomes of AIT by decentralizing management approaches of Canal Systems designed using MIT is also discussed.

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Guillermina - 20 WEEKS AGO
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Hace tiempo que lo denunciamos. Sin embargo el poder mundial nada ha hecho por frenarlo. La quema de bosques, el efecto invernadero, han provocado la licuefacción del permafrost. El aumento de la temperatura es innegable. Se descongelan aceleradamente glaciares, barreras de hielo, aumenta el nivel del mar, provocando inundaciones. Nunca antes habían sido tan agresivos los huracanes. Los refugiados ambientales son cada vez más numerosos. Basta de emitir tanto dióxido de carbono a la atmósfera. Dejen de manipular la ionósfera. Basta de cambiar el clima a propósito. Los países centrales y el espíritu cortoplacista lo olvidan rápidamente. Qué hacer? Revertir rápida y urgentemente las causas que provocan el calentamiento global del planeta, so pena de desaparecer como especie. Cambio de hábitos consumistas, ya!
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Saad ul Malook - 20 WEEKS AGO
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The present industrial advancement and the corporate capitalism has made the environmental pollution more hazardous for mankind. The USA is responsible for sabotaging all the efforts for improving the global warming situation and it doesn't bother about the obligations for the betterment of climatic conditions. The USA doesn't recognize its responsibilities. It makes the situation risky and more worsened just for the profit of a few dollars.
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Climate Change Natural Man Made: Causes And Facts

Climate Change Natural Man Made: Causes and Facts is the first article in a series of 6 on the topic of climate change. There are many issues that should be discussed at the highest levels and at the water cooler alike. Although in a surprising twist, you might not know what the top-ranking global issue threatening our world is. The one issue that is more urgent and more pressing than all of those mentioned above. The one that threatens our very existence. Recommended:  Climate Agreement Paris And The Denial Of President Trump Climate change! Already in 2013, before the Paris Climate Agreement became a 'thing', 56% of countries questioned in an international survey indicated that global climate change would be a major threat to their country. This number rose to 63% in 2017, before reaching 67% one year later, in 2018.   Natural Man Made This first article in my series on climate change will discuss what, exactly, climate change entails. It summarises and reflects the commonly accepted scientific consensus on the systems that make and influence our climate, describing the immense complexity. Just to be perfectly clear: this article is not meant to point the finger at anyone. It is not taking a side in the debate of man made versus natural occurrence. The article is meant to explore the concept from the most objective standpoint possible. It will inevitably include words like ‘estimate’, ‘approximate’, ‘observed’, ‘hypotheses’, ‘models’ and ‘uncertainty’ - as those are the perfect representation of the complexity of the issue and the widely varying opinions on the topic.   Words are playing an important part as it is, as they form such an important part of how individuals look at climate change and perceive it. We experience climate change using our specific set of constructs and references. People might speak of their observations on a local level, citing their climate-related life experiences. Farmers use terminology that distinguishes between great and not so great seasons, linking that season’s weather to the related harvest yield. Scientists look at longer periods of time and distinguish trends on a larger scale. These perceptions all have one thing in common: they look at change.   Climate Change! What Is It? Let’s just dive right in with the most significant question - that has proven to be the most difficult to answer. In a nutshell, climate change occurs when certain changes in our earth’s climate system lead to new weather patterns that last for at least a number of decades, although they could just as easily last for millions of years.   This definition is pretty much stone-clad, although it offers some definitions that are not as definitive. What does, after all, make up this climate system that is so determinant? Most will agree that our climate system is composed of five elements that interact with one another: Atmosphere , or the air around us Hydrosphere , or the water surrounding our continents Cryosphere , or the ice and permafrost covering our poles Biosphere , or all living things and beings Lithosphere , or the surface soils, rocks and sediments These elements rely on each other, which is why even subtle changes in one of them will have a big impact on the system as a whole. The system is ultimately powered by the sun, where it gets most of its energy from - with only a small portion taken from the earth’s interior. At the same time, the climate system ‘radiates’ energy as well, sending it off in outer space.   This balance of incoming and outgoing energy, combined with the way it passes through our climate system, makes up our earth’s energy budget. If there’s more energy incoming, we say that the earth has a positive energy budget - meaning that the climate system as a whole is warming. On the other hand, if there’s a greater outflow of energy, we have a negative energy budget, letting the earth experience a period of cooling. The incoming energy ‘flows’ through the climate system, being distributed around the globe by winds, ocean currents and other similar mechanisms. This results in what we know as the weather - as well as the long-term averages of weather, that we refer to as climate. Thus, it will not hold up if you refer to one bad summer as indicative of climate change - it will, though, if there are notable changes in the long term average. This, and only this, is what we refer to as climate change. {youtube}                                                    Scientist Explains Climate Change Using Maps | WIRED                                                     Climate Change Natural Man Made: Causes And Facts Climate Change: Man Made Or Natural Unfortunately, for all intents and purposes, 'climate change' has become the catch-all phrase for a vastly divergent group of concepts - including being used as a technical description of the process at hand as well as a noun that is used to describe the problem.   Recommended:  Climate Change: Water Scarcity, Hunger, Agriculture And Food Consequently, both the terms ‘global warming’ and ‘climate change’ are used interchangeably, now often being used to reflect man-made climate change (or global warming) in particular. This bias continues to exist even in popular scientific literature, making it harder to form a clear image of the actual problem. In order to avoid any confusion, this series of articles will utilise the most commonly accepted definition of climate change: a change in the statistical proporties of the climate system when considered over long periods of time, regardless of cause. This excludes weather evens like El Niño, that represent fluctuations over periods shorter than a few decades. Taking the explanation above into account, it will not be hard to see why these changes could partially result from the so-called ‘internal variability’, where the energy budget is altered by natural processes that make up our climate system, and partially by human activities. The carbon cycle, showing the movement of carbon between land, the atmosphere and the oceans. Yellow numbers are natural fluxes and red numbers are human contributions in gigatonnes of carbon per year. White numbers indicate stored carbon (The Carbon Cycle , NASA). History Of Climate Change When looking into the causes and historical trends for climate change as a whole, to better understand both natural processes and human influence, researchers usually focus on evidence as preserved in typical climate proxies such as ice cores, ancient tree rings, geologic records of changes in sea level and glacial geology. Photo by: B.A.S. Dr E.C. Pasteur removing an ice core from the core barrel during drilling on an ice dome on Berkner Island. The collaborative drilling programme with the Alfred-Wegener-Institut, Bremerhaven, Germany recovered ice cores to study the climate and atmospheric conditions of the Weddell Sea region over the past millenium. These ‘time-capsules’ allow us to understand climate in a way we were unable to before. Before the 18th century, scientists were blissfully unaware of this thing called ‘climate’ and how earlier, prehistoric climates could be different from their own time period. Only towards the end of this century did they find evidence of changes in climate in geological ages long past, using the methods above. Through paleoclimatology, we try to study the changes in climate taken on the scale of the entire history of earth. Historical climatology, on the other hand, studies historical changes in climate and maps out the effect that they have had on human history and development. This heavily relies on the written word, hidden in sagas, chronicles, maps and literature; as well as on paintings, drawings or rock art to form an adequate picture of the past. It has been claimed that climate changes in the past are hiding in plain sight: driving changes in settlements and agricultural patterns, or even going so far as linking the rise and fall of various civilisations to significant climate events. Those have often been included in archaeological records, making it a silent witness (or perhaps even instigator) to many of the world’s biggest historical moments. Tracing Climate Change’s Tracks Today, far less ‘guessing work’ is involved. We have satellites circling the earth that capture the incoming and outflowing radiation, making it relatively easy to track our energy budget - and with that, a significant portion of climate change. Such technological advances have only made it easier for us to deepen our research in the phenomenon, helping us to understand the working of our climate system. The incoming and outflowing radiation When looking specifically at proof supporting the current climate change, there are several ways to go - aside from data captured by these satellites. These include reports on extreme weather events, as well as temperature records and the disappearance of ice all around the world. These graphic and very physical pieces of evidence are chosen for their irrefutability and comprehensibility alike: no scientific background is needed to ‘understand’ the impact of ice caps collapsing before our very eyes. Melting ice caps are actually not just used to sensationalise climate change. Glaciers are some of the most sensitive indicators of climate change. They are in many aspects representative of the world’s energy budget: with the size depending on the balance between snow input and melt output. Hence, warming temperatures will cause glaciers to retreat - unless enough snow is ‘inputted’ to balance it out. Through a world glacier inventory, that also relies on satellites to track their size and location, scientists can get a clear picture of what is happening to this ‘glacier budget’ and, hence, with the world’s energy budget at large. And, spoiler alert, it hasn’t been looking good for the past decades, with significant shrinkages found all around the world. Related with this subject is the Albedo effect. Albedo is a measure of the reflectivity of a surface. The albedo effect when applied to the Earth is a measure of how much of the Sun's energy is reflected back into space. Overall, the Earth's albedo has a cooling effect. (The term ‘albedo’ is derived from the Latin for ‘whiteness’). Further evidence of climate change can be found in the Arctic sea. Mostly covered in sea ice, it has seen a major decline in both the extent and the thickness. Through satellite images, we have been able to establish that each decade, some 13.2% of sea ice is disappearing.   Recommended:  Waste In Space Will Be Fetched By The CubeSail Garbage Truck Melting glaciers and sea ice are at the core of a whole other problem, being the rising of sea levels. This is another stable indicator of climate change’s progression, showing how the earth’s temperature correlates with sea levels. Through the dating of coral reefs, coastal sediments, marine terraces, limestones and nearshore archaeological remains, it is possible to establish the sea level for periods of which we roughly know the average global temperature. For instance, in the early Pliocene, global temperatures were some 1-2˚C warmer than they are today. Sea levels were also 15-25 meters higher than today, painting a relatively grim image for our future - especially for those living in coastal regions. Other indicators of climate change that are used today are changes in ice cores, cloud cover and precipitation, vegetation, forests, pollen and animals. Modern techniques will stop at nothing to figure out how climate change has influenced any of these in the past and thus predict what our future might look like if global temperatures are to rise even further. Climate Forcing Mechanisms Through such historical and empirical research, several factors have been identified that pretty much ‘shape’ our climate as they are capable of influencing the energy budget, that frail balance determinant of climate. These are referred to as climate forcing or ‘forcing mechanisms’. The way in which the five elements making up the climate system respond to such forcing mechanisms varies. This feedback can serve to amplify or diminish the initial ‘forcing’, either bringing along disruption or stabilisation of climate. Oceans and ice caps, for instance, are relatively slow in responding - whereas the atmosphere, biosphere and lithosphere can be much quicker to react.   For all of these elements, there is a certain threshold factor. Up until reaching that threshold, not much change will be noted - but this will change quickly upon passing it, setting major and often irreversible changes in motion. Forcing mechanisms can be internal or external and lead to a slow or fast response of the climate system: a volcanic eruption will lead to a sudden cooling, while the warming of ocean water will have a much longer ‘time to impact’. Internal Forcing Mechanisms Internal forcing mechanisms are the natural processes that opponents of the man-made theory often point at as the main culprit. These occur within the climate system itself - within one of the five elements that I mentioned earlier, to be exact. Any natural changes in one or several of these five elements might lead to internal ‘climate variability’, or natural climate change.   One example of such a forcing mechanism is a change in the type and distribution of species. Life, as it stands, affects climate through its role in the carbon and water cycles - or by triggering various other mechanisms such as:   cloud formation, to reflect sunlight evaporation and transpiration, from land and ocean surfaces to the atmosphere and weathering , or the breaking down of rocks, soils, wood and minerals   Evaporation and transpiration, from land and ocean surfaces to the atmosphere In the past, several instances have been noted where life was ultimately decisive in changes to the climate. We are talking about millions or even billions of years ago, where vascular land-plants, marine phytoplankton, or grass-grazers have been acting as the main culprit. Another example of an internal forcing mechanism is a change in ocean-atmosphere circulations. As it turns out, when the hydrosphere (oceans) and the atmosphere work together, pretty significant things can happen. Together, they can create spontaneous internal climate variabilities that can last for years - or even decades - on end.   This includes El Niño and his sister La Niña, both of which cause a periodically repeated reversal of the direction of movement, as well as the lesser known Pacific decadal oscillation and the Atlantic multidecadal oscillation. All of these redistribute heat from the deep ocean to the atmosphere and/or alter the cloud/water vapor/sea ice distribution. This has a pretty profound impact on the earth’s energy budget. External Forcing Mechanisms External forcing mechanisms are those that are ‘out of the ordinary’, so not directly caused by the climate system itself. Even here, there might still be an element of natural causes - including changes in solar output, changes in the earth’s orbit, or volcanic eruptions. Some famous examples are the Milankovitch cycles or the Vostok ice core. A first example of external forcing mechanisms, solar output, has been a notorious contributor to climate change for centuries. There have been some pretty significant variations in solar activity, based on observations of sunspots and beryllium isotopes.   There was, for instance, a period of remarkably few sunspots in the late 17th century - the Maunder Minimum. And while some of those periods have been long term, others have been pretty short term. Either way, they have a big impact on global climate: the Maunder Minimum has been cited as one of the main triggers of the Little Ice Age that took place between 1550 and 1850 AD.   The exact effect of solar variability on global temperatures has not yet been firmly established, with a 2010 study by CERN suggesting that ‘ the effects of solar variability on temperature throughout the atmosphere may be contrary to current expectations. ’ Working on a theory outlining aerosol formation in the lower atmosphere, it may very well be that these are (partially) driven by human activities as well.   Milankovitch cycles A second example of external forcing mechanisms are the orbital variations of our planet. Even the slightest variations in the motion of our earth will change how much sunlight reaches the earth’s surface in particular areas during particular seasons. Such kinematic changes can stem from the tilt angle of the earth’s axis of rotation, the precession of earth’s axis, and changes in the earth’s eccentricity.   When you combine these three, so-called Milankovitch cycles are produced, that influence our climate to the extent that they have been linked to glacial and interglacial periods in the past, as well as the advance and retreat of the Sahara. Powerful effects of a relatively minor adjustment in our earth’s position. Thirdly, volcanic activity and plate tectonics have been known to be climate-changers as well. Some eruptions, those injecting at least 100,000 tons of SO2 into the stratosphere, have had a significant impact on our climate. SO2 and sulfate aerosols are responsible for the creation of a sulphuric acid haze, capable of absorbing and scattering solar radiation before it reaches the surface. This leads to a cooling effect that can last for several years. For instance, the eruption of Mount Pinatubo in 1991 lowered global temperatures by an average of 0.5 °C for three whole years. Earlier, the eruption of Mount Tambora in 1815 has been documented to have caused the ‘year without a summer’. Yet, for comparison’s sake, the impact of volcanic eruptions does not even come near the effect of human emissions: humans generate some 100-300 times the amount of carbon dioxide emitted by volcanoes.   Anthropogenic Mechanisms This leads to the next, obvious point. The majority of external forcing mechanisms are anthropogenic, or man-made. Most notably, it includes greenhouse gasses and dust particles in the atmosphere. The current scientific consensus is that our climate is changing in a largely irreversible manner, and that those changes are in part caused by human activities. This is backed by a strong, credible body of evidence and runs through multiple lines of research. It is pointing at the increase in CO2 levels as the most concerning factor influencing climate change. Our earth’s atmosphere, commonly known as air, surrounds our planet and is one of the main players of the climate system. It should contain a large amount of nitrogen (78.09%), oxygen (20.95%), a small amount of argon (0.93%), and an even smaller amount of carbon dioxide (0.04%).   Now that carbon dioxide in our atmosphere is rising steadily, it is not hard to see how this can cause a misbalance in the atmosphere, setting in motion a potentially disastrous sequence of global warming. This increase in emissions is largely, aprtly resulting from fossil fuel combustion, use of aerosols, and cement manufacturing. Although there are several other factors, including animal husbandry, deforestation and ozone depletion. All man-made or, at least, man-related issues. The IPCC has stated that the human-caused change in our climate will impact both human and natural systems on all continents and across the oceans. A pretty definitive and clear statement that serves to remind us of the actual mechanism driving this particular wave of climate change that we are riding today. And, just in case it is not clear yet: this mechanism is partly us.   Thankfully, we are also 'a' mechanism that could be used to avoid partly the worst consequence - if only we put our minds to it. The next article in this series will look at who is actually on board to take action and help us ride out this particularly worrisome climate wave. Before you go! Recommended:  Five Minutes To Midnight: Climate Change Action Fighting The Clock Did you find this an interesting article or do you have a question or remark? Leave a comment below. We try to respond the same day. Like to write your own article about sustainability? 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