"Today we expect accurate weather forecasts, out to the 5th day or more."
"Dynamical climatology as it was called in the Met office in the early 70s"
"Climate is what you expect, weather is what you get" - Mark Twain
"Climate science is about understanding the Earth's climate, through a combination of theory, observations and computational models. Understanding forcings on the climate system."
"To be a climate scientist, you have to be a polymath."
Edmond Halley, 1656 - 1746
"An Historical Account of the Trade Winds, and Monsoons, Observable in the Seas between and near the Tropicks, with an Attempt to Assign the Phisical Cause of the Said Wind," 1686.
George Hadley, 1685 - 1768
The Hadley Circulation: the diurnal rotation, relative motion of air; towards the equator - easterly wind. If air converges and rises, it has to descend somewhere else for mass continuity.
Earth's Rotation and the Coriolis Force
"If a body is moving in any direction, there is a force arising from the Earth's rotation, which always deflects it to the right in the northern hemisphere, and to the left in the southern."
Carl-Gustaf Rossby, 1898 - 1957
Established theory of planetary waves (now called Rossby Waves) as a result of Earth's rotation and the stratification of the atmosphere/ocean
John Tyndall, 1820, 1893
The Greenhouse Effect was necessary based on solar radiation and temperature of Earth's surface.
Svante Arrhenius, 1859 - 1927; the following stated in 1896
First prediction of global warming: "... any doubling of the percentage of carbon dioxide in the air would raise the temperature of the earth's surface by 4°C; and if the carbon dioxide were increased fourfold, the temperature would rise by 8°C."
"... The enormous combustion of coal by our industrial establishments suffices to increase the percentage of carbon dioxide in the air to a perceptible degree."
But he thought it was a good thing to increase the temp for colder regions and "increased crop production for the rapid propagation of mankind"
Pressure of drought due to massive el nina preventing monsoon season preempts regional interest in forecasting by looking at the local patterns and relationships.
Sir Gilbert Thomas Walker: 3rd British Director of the Indian Meteorological Department from 1904 - 1924
Pioneered statistical climate forecasting - using human computer performing a mass of statistical correlations using data from around the world
"I think that the relationships of world weather are so complex that our only chance of explaining them is to accumulate the facts empirically."
Paleoclimate perspectives
Milankovitch Cycles
Medieval Warm Period
Little Ice Age
Earth Observation marked the first transformation of climate science!
We almost take this for granted - we have a view (many views!) of the distribution of clouds about the Earth.
2009: Trenberth et al: Global Energy Flows; the weather is what achieves the balance of energy. the weather defines the earth's climate
Describes how incoming radiation, reflections, atmosphere all interact! Very complex.
Global water cycle: phase changes of water move heat around the system; earth's climate supports water in three phases: gas, liquid, solid. Moving between these is what makes things "interesting."
General Circulation Models: the second transformation of climate science
1955: Norman Phillips, computational model simulating weather systems
1965: Smagorinsky, Manabe and Holloway: Numerical results from a nine-level general circulation model of the atmosphere (no water cycle, simple radiative cooling)
1965: Manabe, Smagorinksy, Strickler: Simulated Climatology of a General Circulation Model with a Hydrologic Cycle
Parameterize became how to tackle unresolvable processes
Supercomputing: the third transformation of climate science
Water cycle is fundamental to the climate system - and at lower resolution it's not properly represented. Fractal patterns. Same with ocean modeling.
Climate science has evolved to earth system science, always more complex and more interdisciplinary.
Climate models are the laboratories of climate science. (commentary: this could be problematic, no? If the model is incomplete or flawed?)
warming: the fourth transformation**
Charles David Keeling, Keeling Curve.
1974: Manabe & Wetherald publish The Effects of Doubling the CO₂ Concentration on the Climate of a General Circulation Model
With anthropogenic forcings, you can reproduce temperature changes, with natural only you can not.
Anthropogenic change is driving extreme events
"... one flap of a sea-gull's wing may forever change the future course of the weather" - Edward Lorenz, 1963
Questions for the future:
Can we provide society with a roadmap indicating what climate variations and changes may be expected to occur, where, and with what implications?
How can we make society more resilient and better prepared for hazardous weather and climate extremes arising from climate variability and change?
Do we know what levels of climate change could be dangerous, where and for whom?
What should society do to mitigate and adapt to climate change to avoid its worst impacts?
