01 Climate system Ladislava Řezníčková, MSc, PhD 1. What is the climate system? • Components of the climate system • Positive and negative climate feedback 2. Natural causes of climate change • fluctuations in solar radiation, orbital changes • distribution of continents and oceans, volcanic eruptions, vegetation • atmosphere and ocean relationship • changes in the composition of the Earth's atmosphere Content Weather vs Climate Weather Climate • the state of the atmosphere at a particular place and time as regards heat, cloudiness, dryness, sunshine, wind, rain, etc. • short-term changes in the atmosphere • the weather conditions prevailing in a specific area over a long period • long-term characteristic weather regime (long-term average state of the atmosphere in a certain place), conditioned by the energy balance, atmospheric circulation, the character of the surface and human interventions How does the climate change? Climate system ATMOSPHERE LITHOSPHERE HYDROSPHERE CRYOSPHERE BIOSPHERE By Femkemilene - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=79629050 Figure from IPCC (2007) Why is the climate changing? Natural vs. anthropogenic causes Climate Change – natural causes • fluctuations in solar radiation, orbital changes • distribution of continents and oceans, volcanic eruptions, vegetation • atmosphere and ocean relationship • changes in the composition of the Earth's atmosphere ● 73% hydrogen, 25% helium, 2% the other elements ● thermonuclear reactions: 4 H → 1 He + energy production The Sun ● solar activity – sunspot cycle – Wolf number (relative sunspot number) The Sun Wolf number since 1750 The electromagnetic spektrum Comparison of different types of light, including wavelength size, and frequency. https://hubblesite.org/contents/articles/the-electromagnetic-spectrum https://en.wikipedia.org/wiki/Sunlight Energy distribution Global Atmospheric Circulation Without the Earth’s rotation, tilt relative to the sun, and surface water With the Earth’s rotation, Earth’s tilt and real surface Hadley cell Ferrel cell www.noaa.gov L H L L H H Polar cell Energy distribution Global atmospheric circulation https://www.youtube.com/watch?v=xqM83_og1Fc Energy distribution Thermohaline Circulation Animation: https://upload.wikimedia.org/wikipedia/com mons/a/ab/Thermohaline_circulation.svg A summary of the path of the thermohaline circulation. Blue paths represent deep-water currents, while red paths represent surface currents. Climate Change – natural causes • fluctuations in solar radiation, orbital changes • distribution of continents and oceans, volcanic eruptions, vegetation • atmosphere and ocean relationship • changes in the composition of the Earth's atmosphere The Sun – The Earth Changes in eccentricity 100.000 years cycles Changes in obliquity (axial tilt) 41.000 years cycles Axial precession 21.000 years cycles Eccentricity Precession Obliquity Milankovitch Orbital Cycles Animations: https://climate.nasa.gov/news/2948/milankovitch-orbital-cycles- and-their-role-in-earths-climate/ Climate Zones https://www.youtube.com/watch?v=7yiqkOH1GTQ Climate Change – natural causes • fluctuations in solar radiation, orbital changes • distribution of continents and oceans, volcanic eruptions, vegetation • atmosphere and ocean relationship • changes in the composition of the Earth's atmosphere Maritime vs. continental climate Maritime climate in northwestern and nothern Europe Highland climate Vegetation altitude zones Volcanic eruptions https://berkeleyearth.org/archive/volcanoes/ Climate Change – natural causes • fluctuations in solar radiation, orbital changes • distribution of continents and oceans, volcanic eruptions, vegetation • atmosphere and ocean relationship • changes in the composition of the Earth's atmosphere The Water Cycle https://www.usgs.gov/special-topic/water-science- school/science/water-cycle?qt- science_center_objects=0#qt- science_center_objects https://education.nationalgeographic.org/resource/800px-water-cycle/ The most important are: • evaporation • transpiration • condensation • precipitation • runoff ENSO - El Niño-Southern Oscillation • Hess, D. (2014): McKnight's physical geography: a landscape appreciation. 11th ed. Harlow: Pearson. Pearson new international edition. ISBN 978-1-292-02091-4, 143-148. • https://www.youtube.com/watch?v=WPA-KpldDVc Using recommended sources, study basic information about the phenomenon called ENSO (where and why it occurs, processes in the ocean and the atmosphere, normal patterns, El Niño, La Niña, regional and global effects on weather/climate). SELF-STUDY Climate Change – natural causes • fluctuations in solar radiation, orbital changes • distribution of continents and oceans, volcanic eruptions, vegetation • atmosphere and ocean relationship • changes in the composition of the Earth's atmosphere Changes in the composition of the Earth's atmosphere https://www.britannica.com/topic/evolution-of-the-atmosphere-1703862 Evolution of the atmosphere https://www.youtube.com/watch?v=z1Ieb- OAoZA&list=PLW1sGr2pZxWxsgJPRPAsq4go_M4nD7Z4m Climate feedbacks + Positive climate feedback = increasing effect of climatic factors - Negative climate feedback = reducing effect of climatic factors • the amount of solar radiation reflected by a surface (% or decimal value) Albedo A sampling of Earth's colors Credit: UCAR SciEd with NASA image https://scied.ucar.edu Albedo The percentage of reflected solar radiation relative to various surface conditions White objects (e.g. fresh snow) – high albedo Dark objects (e.g. dark soil, ocean) – low albedo Climate feedbacks + Positive climate feedback = increasing effect of climatic factors - Negative climate feedback = reducing effect of climatic factors + Ice-Albedo Feedback + Water Vapour Release www.thisbluemarble.com Climate feedbacks + Carbon Release https://www.arcticwwf.org/newsroom/features/putting-a-lid-on-methane- emissions-before-its-too-late/ Climate feedbacks - Evaporation and Clouds https://actionrenewables.co.uk/news/what-are-climate-feedbacks/ Thank you for your attention • Hess, D. (2014): McKnight's physical geography: a landscape appreciation. 11th ed. Harlow: Pearson. Pearson new international edition. ISBN 978-1-292-02091-4 • http://www…. References