The Physical Components and Processes of the Planetary System –

In view of global environmental changes, the fact that the wide-ranging sub-stance and energy cycles, as well as the food chain, are closed through the atmosphere is also of critical importance. With its rapid processes bridg-ing great distances, the atmosphere ‘cuts short’ feedbacks between other ter-restrial systems and provides a direct link between remote areas of the Earth.

The analysis of long sets of data of different climatic characteristics has led to the conclusion that, in such quantities, there are simultaneous or lagged resonances (so-called ‘teleconnections’) at relatively remote locations of the Earth. A typical example of this process is the phenomenon known as ENSO (El Niño–Southern Oscillation), in which there is a close link between the

recurrent cold water upwelling along the South-American coast of the Pacific Ocean and the airflow conditions along the Australian coast (air pressure dif-ferences, precipitation, extreme weather, etc.). Thus, the atmosphere—due to its chemical composition and its role in conveying impacts—has a key influence on the state of the other spheres of the Earth.

A closer look at the current chemical composition of other planets and the chemical composition of ‘previous’ atmospheres of the Earth reveals that the presence or absence in the atmosphere of certain substances, whose quantity is minute compared to the planet as a whole, determines the character of the entire global ecosystem. To take an illustrative example, if there was no carbon dioxide in the atmosphere of our planet—and the total amount of CO2 in the atmosphere is less than the mass of the Mátra Moun-tains in Hungary—, the average surface temperature of the Earth would be around -15 degrees Celsius, and the planet would probably be a frozen world without life. Another substance—whose quantity in the atmosphere is even smaller—is ozone, which was indispensable for the biosphere to come into existence and continue to exist on land areas. The total volume of this sub-stance in the atmosphere is estimated at approximately one billionth of the mass of terrestrial biomass. One of the findings of the past 50 years of air observations—an unexpected one—is the existence of a major unidirectional change in the chemical composition of the atmosphere.

Global environmental change and its main form, climate change, consti-tute one of the most topical socio-economic issues. It has already become clear to both economic and political decision-makers and the people con-cerned about the environment that such changes—which entail natural disas-ters, hurricanes, drought and rising sea levels in certain parts of the Earth—

pose a serious risk to all the economies of the world. The climate in its broad sense—i.e. the spatial and temporal evolution of the state of the air and of the terrestrial systems interacting with it—is one of the most complex systems ever studied. The climate system is made up of the atmosphere, the sur-face of the Earth, the oceans, the biosphere, and the cryosphere. It is a system of mutually interacting factors, in which the climate of the Earth is determined by the complex set of physical and chemical processes taking place on different temporal and spatial scales. The climate system can be regarded as a physical (natural) subsystem of the planetary system.

The components of the climate system

Source: J. Bartholy and R. Pongrácz (eds.), Klímaváltozás [Climate Change], ELTE, Buda-pest, 2013, bioszféra = biosphere; talajfelszín = soil surface; sugárzás = radiation; légkör = atmosphere; felhő = cloud; szél = wind; bio-geokémiai ciklus = biogeochemical cycle;

üvegházgázok = greenhouse gases; csapadék = precipitation; párolgás = evaporation; óceán-légkör hőcsere = ocean/atmosphere heat exchange; lefolyás = run-off; tengeráramlatok = ocean currents; óceán = ocean; tengeri jég = sea ice; jégtáblák = ice floes; krioszféra = cry-osphere

From the perspective of climate modelling, the factors and impacts determin-ing the climate can be divided into three major groups:

1. The extraterrestrial impacts include changes in the radiation of the Sun, which control the climate system, as well as the effect of astronomical bodies causing ebb and flow, and the cosmic particles entering the gravitational field of the Earth.

2. The terrestrial impacts consist of the interactions between the four spheres of the Earth:

• Surface of the Earth: It includes the arrangement of the continents, plate tectonic movements and the terrain. Soil characteristics, vegetation types, and the extension of free water surface are slowly changing fac-tors, while soil moisture, vegetation cycles, and snow and ice cover are factors that change rapidly.

• Oceans: Besides the atmosphere, the role of oceans is the most signifi-cant due to the fact that 97% of the Earth’s water resources are located

in the oceans, as well as due to their high heat capacity and the charac-teristics of their fluid mechanics systems.

• Cryosphere: The snow and ice cover of the Earth is made up of the seasonal snow cover of land areas, the ice caps and ice sheets of the con-tinents, the glaciers of mountains, and sea ice. The heat transfer between the cryosphere and the atmosphere, as well as the cryosphere’s capacity to reflect radiation, are considerable.

• Biosphere: The role of flora, fauna and human activities is mainly re-flected in the CO2 cycle and in the release of various aerosols into the atmosphere.

3. The most important of the factors inside the atmosphere is its capacity to absorb and/or reflect radiation, which is closely related to the development of the greenhouse effect. Air chemical processes (interactions of ozone, CO2, water vapor and different aerosols with the atmosphere and with each other) and the dynamics of the atmosphere (creation and development of atmos-pheric motion systems of different scales from small dust devils to general circulation) are also essential. The interactions between the components of the climate system can be broken down into positive and negative feedback processes: the first ones enhance, while the latter mitigate changes. Feedback mechanisms related to heat/ice albedo, water vapor and clouds are the most important in terms of global warming.

7.1.2. The Process and Trends of the Greenhouse Effect – A Key Factor in Global Changes

The world’s population is growing by one billion per decade. In the last two centuries, global energy demand has increased by approximately 2% per year. The energy and food needs of the developing world grow by 1–2% per year, while the population of developed countries is constantly aging. The revolution in the chemical industry in the past decades has led to the creation of some 5 million synthetic compounds, the use and elimination of which (e.g. residues accumulated in the food chain, microplastics) greatly aggravate the environmental condition of the Earth. If the current trends remain un-changed, two-thirds of the species on the Earth could become extinct by 2100. The drivers of global environmental change are closely related to other complex processes, which are also global in nature.

System of relations of global environmental change

The modelling of the planetary system absolutely requires that the process of greenhouse effect be understood from a physical perspective—its causes from a socio-economic perspective—and described in mathematical terms.

It has been known theoretically since the end of the 19th century and through reliable measurements since 1958 that the carbon dioxide, methane and ni-trous oxide content of the atmosphere is rapidly increasing as a result of the use of fossil fuels, decreasing forest areas and large-scale agricultural activ-ities.

The Physical Background to the Greenhouse Effect

When the rays of the Sun reach the Earth’s surface, a part of the energy is absorbed, thus warming the soil and the oceans. The remaining energy is re-flected in outer space, but a part of it is absorbed by the atmosphere, thus raising further the temperature of the planet. This is known as the ‘house effect’, since the atmosphere behaves like the glass walls of a green-house, keeping the interior space warm. The greenhouse effect is caused by the presence of gases such as water vapor, carbon dioxide, methane and ni-trous oxide (known as greenhouse gases) in the Earth’s atmosphere. Without this natural greenhouse effect, the average temperature of the surface of the Earth would be approximately 33 degrees Celsius lower than at present;

therefore, the greenhouse effect is a natural process that is vital to life on Complex impact factors

•climate change

•loss of biodiversity

•environmental load

•land use

Natural resources

•water resources, soil, air

•forests, ecosystems

•landscape; spatial structure

•renewing energy sources;

Socio-economic conditions

•ownership; markets

•human resources; knowledge

•morals; ethics

•health; well-being;

General drives

•globalization / regionalism

•consumption patterns

•EU funds

•policies

employment; quality of life; harmony with nature;

population retention; security, etc.

Earth. (This is why these compounds cannot be labeled as ‘harmful sub-stances’, since it is not their atmospheric presence that causes problems but their increasing quantity.)

The evolution of the quantity of the main greenhouse gases in the atmosphere over the past 200 years

CO2

(carbon dioxide)

CH4

(me-thane)

N2O (nitrous

oxide)

HFC (halo- fluoro-carbon)

PFC (per-

fluorocar-bon)

SF6

(sulphur hexafluo-ride) concentration

before the indus-trial revolution

280 ppm 700 ppb 275 ppb - - -

current concen-tration (2014)

405 ppm 1,830 ppb 350 ppb 0.15 ppb 0.07 ppb 0.05 ppb growth rate of

concentration

0.4 % per year

0.8% per year

0.3% per year

7% per year

2% per year

? average

resi-dence time in the atmosphere

50–

200 years 8–

15 years

120 years 50–

200 years

approx.

3,000 years

3,200 years

global warming potential (GWP) (on a scale of 100 years)

1 23 298 1,400–

15,000

6,000–

15,000

22,000

Source: IPCC, Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, [Core Writing Team, R.K. Pachauri and L.A. Meyer (eds.)], IPCC, Geneva, Switzerland, 2014, pp. 1–31.

Currently, the carbon dioxide content of the atmosphere is more than a third higher than before the industrial revolution, primarily due to the in-creasing use of fossil fuels and extensive deforestation. Through the natural process—through the carbon dioxide absorption processes of plants and oceans, among others—, this gas is released into the atmosphere and then gets out of it in much larger quantities than those mentioned above. This means that human activities have upset the natural dynamic balance (the natural circulation of carbon dioxide and other substances) in such a way that natural carbon sinks are no longer able to absorb the extra carbon dioxide released into the atmosphere by non-natural means. The release into the at-mosphere of one new methane molecule increases the greenhouse effect 23 times as much as a carbon dioxide molecule, the release of a nitrous oxide molecule 300 times, while some halogenated hydrocarbon molecules tens of thousands of times as much.

Increased greenhouse gas emissions lead to a change in the thermal system of the atmosphere, a so-called radiative forcing. The spatial distribution of solar energy and its evolution in time are the primary drivers of all weather and climate processes. A part of the energy reaching the outer limits of the atmosphere is reflected by clouds, the surface and the solid particles sus-pended in the atmosphere, and—taking into account the atmospheric absorp-tion as well—approximately half of the energy reaches the surface of the Earth. A part of the infra-red thermal radiation emitted by the warmed-up surface is absorbed and reflected by clouds and the greenhouse components of the atmosphere, thus ensuring the balance between net incoming radiation and outgoing thermal radiation over a long period of time and on the whole of the Earth. Thus, considering the Earth-atmosphere system as a whole, greenhouse gases do not ‘heat’ our planet but change the structure of the vertical distribution of temperature by causing the lower layers of air to warm up and the higher ones to cool down.

Atmospheric radiation transmission and the greenhouse effect

Source: IPCC, Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, [Core Writing Team, R.K. Pachauri and L.A. Meyer (eds.)], IPCC, Geneva, Switzerland, 2014, pp. 1–31.

The exploration of the greenhouse effect mechanism is not the result of the past few decades but of nearly one and a half centuries. As early as the 1860s,

scientists studying the atmosphere recognized the important role of trace gases in the pleasant climate of the Earth. In 1861, the first article by John Tyndall¹⁹⁹ about the role of water vapor in heating the atmosphere was pub-lished in the English Philosophical Magazine. The study written by Svante Arrhenius in 1896 described the expected atmospheric consequences of the increasing concentration of carbon dioxide due to coal burning.²⁰⁰

Unlike greenhouses used in horticulture, the atmospheric greenhouse effect has some ‘special characteristics’:

• air and cloud particles absorb a large proportion of solar radiation;

• in a certain range (known as the ‘atmospheric window’), the Earth radiation passing through the atmosphere towards outer space is not absorbed by greenhouse gases;

• the winds carrying air masses also play a major role in the free atmos-phere;

• the warm air cannot pass through the glass plate, but there is no such obstacle in the atmosphere (convection).

Greenhouse Gas Emission Trends Globally and in Hungary

Approximately 50% of the anthropogenic CO2 emitted since 1750 was re-leased into the atmosphere in the last 40 years. Despite climate change miti-gation policies, global CO2 emissions doubled from 1975 to 2015. The con-tribution of CO2 emissions from fossil fuel combustion and industrial pro-cesses to the overall increase of greenhouse gas emissions amounted to nearly 80% from 1975 to 2015.

Anthropogenic greenhouse gas emissions depend basically on population, economic activities, lifestyle, energy use, land use, technologies, and climate policy. There are several emission reduction pathways, which are probably able to keep the level of warming below 1.5 °C compared to pre-industrial levels. These pathways would all require substantial cuts in emissions over

199 J. Tyndall (1861): ‘On the Absorption and Radiation of Heat by Gases and Vapours, and on the Physical Connexion of Radiation, Absorption, Conduction.–The Bakerian Lecture’, The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, series 4, vol. 22, pp. 169–

194, 273–285.

200 J. Bartholy and R. Pongrácz (eds.) (2013:, Klímaváltozás [Climate Change], ELTE, Budapest, 2013, http://elte.prompt.hu/sites/default/files/tananyagok/Klimavaltozas/index.html, accessed 20 November 2019.

the next few decades as well as the reduction of CO2 and other greenhouse gases with a long residence time to almost zero by the 2050s.

Without further efforts going beyond the current reduction in greenhouse gas emissions, as a result of global population growth and the increasing eco-nomic activities, global emissions are expected to continue to grow. Accord-ing to the baseline scenarios—which do not include emission reductions ex-ceeding the cuts achieved so far—, by 2100, the global average temperature is expected to increase by 3.7–4.8 °C compared to the average temperature of the period from 1850 to 1900.

The evolution of CO2 concentration and the required emission cuts

Measurement data of atmospheric CO

2

concentration (past)

NOAA, https://www.esrl.noaa.gov/gmd/ccgg/trends/full.html, accessed 20 Nov. 2019.

The quantity of CO2 in the atmosphere is rising steadily, and it has already reached the highest level of the last 800,000 years. The scientists agree that the most dangerous irreversible consequences of climate change can be avoided if the increase in the global average temperature does not exceed 1.5 °C. However, for this to happen, GHG emissions should be reduced by at least 55% worldwide by 2030, and net-zero emissions would be the target for 2050.

Potential CO

2

emission pathways limiting global warming to 1,5 °C (future)

IPCC, ‘Summary for Policymakers’, in Global Warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty, 2018, https://www.ipcc.ch/pdf/special-reports/sr15/sr15_spm_final.pdf, accessed 15 No-vember 2018.

In 2017, Hungary’s greenhouse gas emissions amounted to approximately 64 million tonnes of carbon dioxide equivalent²⁰¹, which constitutes a nearly 40% fall compared to the early 1990s. 6 tonnes per capita emissions are rel-atively low in Europe (the EU average is 9 tonnes per capita). The most im-portant greenhouse gas is still carbon dioxide, which accounts for 78% of total emissions. The main source of carbon dioxide emissions is fossil fuel combustion in power stations, households and transportation. Methane ac-counts for 12% of Hungary’s total GHG emissions, while nitrous oxide for approximately 7%. The main sources of these two compounds are agriculture

201 NIR (2019): National Inventory Report for Hungary 1985–2017, Hungarian Meteorological Ser-vice and National Food Chain Safety Office, 2019, https://unfccc.int/sites/default/files/re-source/hun-2019-nir-15apr19.zip, accessed 20 November 2019.

and chemical production. The analysis of emissions per sector reveals that the energy sector accounts for exactly three-quarters of the total emissions.

Agriculture accounts for 12.1%, industrial processes for 12.3% and the waste sector for 5.8% of greenhouse gas emissions. From the 1990s to the early 2010s, GHG emissions were continuously decreasing, mainly due to the transformation of the structure of the economy (the decline of the energy-intensive heavy industry). However, since 2013 GHG emissions in Hun-gary have been increasing by 3–5% per year, which draws attention to the importance of measures concerning energy efficiency and transportation.

GHG emissions and the index of GDP (2000–2017)

Source: edited by the author on the basis of data from NIR, National Inventory Report for Hungary 1985–2017, Hungarian Meteorological Service and National Food Chain Safety Office, 2019, https://unfccc.int/sites/default/files/resource/hun-2019-nir-15apr19.zip, ac-cessed 20 November 2019.

pozitív szétcsatolás = positive decoupling; fenntartható = sustainable; GHG index = GHG index; GDP index = GDP index

In document integration challenges (Pldal 127-137)