Many Factors Affect Climate

Lots of earthbound and cosmic factors affect climate change. Many of them occur in repeating cycles. Some cycles are predictable and some are not. Solar factors can be seen on the “It’s the Sun” page.

If you want more details, read on.

Trade Winds and Atmospheric Oscillations

For thousands of years, sailors relied on ‘trade’ winds to blow their ships, loaded with cargo, from place to place across the oceans.

“Spanish Galleon”. Licensed under Public Domain via Commons –

Trade winds are relatively predictable in terms of seasonal flow, thus empires expanded and countries were able to trade in goods and services, long before the use of fossil fueled container ships.

Trade winds affect the evaporation of water from the surface of the ocean (among other climate factors) and they are a crucial part of the monsoon cycle in the Southern Hemisphere that brings seasonal, torrential rains to most of Asia. The ‘failure’ of the monsoon season (i.e. not enough rain) means there will be terrible drought and economic disaster for countries in that region.
Dr. Madhav Khandekar grew up in India. He is a former research scientist for Environment Canada and he discusses the monsoon seasons and the fact that 3 to 4 BILLION people are affected by this phenomena.

More on trade winds can be found from the US National Oceanic and Atmospheric Authority website.

Many Atmospheric Oscillations Affect Weather and Climate Patterns

The following map shows the initials and general locations of atmospheric oscillations that affect world climates. These phenomena have cyclical patterns and they interact with other changing conditions on earth – resulting in regional changes in weather patterns or climate. The “ENSO” – El Nino South Oscillation – can have global effects. For more information on each of these, follow the UCAR link below the map.
(Note: Use of the map does not imply endorsement by UCAR of other content in this site.)

El Nino

El Nino, Spanish for the “Little Boy,” occurs in the Pacific Ocean in an unpredictable but recurrent pattern of some 2 to 7 years. It begins when the eastern tropical surface waters of the Pacific become warmer. It is thought that a change in trade winds affect this. That warming then causes more heat and moisture to evaporate, leading to torrential rains off the coast of Ecuador and Peru, where it is normally much drier.

This map shows that the Pacific Ocean is a much larger body of water than the Atlantic Ocean. The forces of an El Nino event can affect the weather of the whole world. This is an entirely natural event.

The El Nino cycle alternates with “La Nina: – a cooling period, which also affects climate and weather, and which is also a natural phenomenon.

Environment Canada’s Weather Glossary

Thermohaline Conveyor

There is a massive ocean current that moves through the oceans of the world, moving warm waters down and cool waters up to the surface.

(Use of this image does not imply endorsement.)

A computer simulation (model) can be seen on this YouTube video.

More on the Thermohaline Circulation currents


Volcanoes affect climate and weather. Volcanoes spew various gases into the air, as well as volcanic ash. If the volcano is powerful enough, some of this material rises above the tropopause (the atmospheric area where jets fly) and once there, the ash can be carried around the world.

Volcanic ash and aerosol emissions can block the sun, causing cooling.

In the latter part of the Little Ice Age (1350-1850) there were several huge volcanic eruptions that made this period of low sunspot activity and general cooling, much worse. A significant volcano was that of “Laki” in Iceland. The release of gases and ash caused a tremendous drop in temperature on the eastern coast of the United States, as you can see on the graph below from the University of Oregon. “The climatic effects of the Laki eruption are impressive. In the eastern United States, the winter average temperature was 4.8 degrees C below the 225 year average.“

Since the end of the Little Ice Age, there was very little volcanic activity in the world from 1912-1963. Some scientists* say this is responsible for at least 0.5 ˚C of the warming since 1850. If this is true, then the warming attributable to human industrial activity might be only 0.3 ˚C – and even that might be in question as other natural factors like solar cycles also affect climate. (* See: “Heaven and Earth” by Ian Plimer pg 219)


Until recently, it was not understood that wildfires may affect climate, but research by Mike Fromm of UN Naval Research Labs has revealed that wildfires, especially those that produce towering ‘fire clouds’ (or Pyrocumulonimbus – Pyro-Cb) can have dramatic impacts on climate. The aerosols from wildfires were once thought to only come from volcanoes.

Source: “Wildfire in Yellowstone NP produces Pyrocumulus cloud” by Brocken Inaglory.
Licensed under CC BY-SA 3.0 via Commons

Here’s more information on how wildfires affect climate:

Pyrocumulonimbus clouds can rise high above the tropopause, where jets fly, and once that turbulent energy, filled with aerosols and ash reaches those heights, it can travel for thousands of kilometers.

Source: Wikiipedia
Pyrocumulus cloud, above the Oregon Gulch fire in Oregon & California, 2014. Aircraft is a F-15C Eagle.

Photo Credit: James Haseltine, Oregon Air National Guard

This image, photographs taken from an F-15C, show a much closer view of a developing pyrocumulus cloud above the Oregon Gulch fire, a part of the Beaver Complex fire. They were taken from an Oregon Air National Guard F-15C by James Haseltine on July 31, 2014, at 8:20 PM Pacific Daylight Time.

Wildfires are often used in developing countries to clear land – but once they start, they are often uncontrollable.

“Global Fires – August and February 2008” by NASA images by Reto Stockli and Jesse Allen using data courtesy the MODIS Land Science Team at NASA Goddard Space Flight Center.
Caption by Holli Riebeek. –
Licensed under Public Domain via Commons

Indonesian wildfires create air pollution issues for much of the South Asian corridor and they burn for a long time as the fire goes into the peat. This area of the world is affected by monsoons and El Nino Southern Oscillations as well as other climate factors that sometimes make these fires worse.

More on the global impact of Indonesian forest fires.

Urban Heat Island

When humans live in heated buildings, in close proximity, on paved surfaces, a bubble called an “Urban Heat Island” is created. This area can be degrees warmer than the surrounding rural areas. However, this may be where surface thermometers are located.

And those thermometers may also be poorly located – like this – in a sheltered area, on ashphalt pavement (which reflects heat), near exhaust fans, cars and other heat exuding devices. Temperature readings here will not be an accurate reflection.

Read more about Urban Heat Island effect

Black Carbon (Soot)

Black carbon, or ‘soot’ is the semi-combusted waste matter, in tiny particles called “fine particulate matter” of 2.5 microns or less (PM2.5). This is the ‘visible’ black smoke from wildfires, campfires, diesel engine exhaust – but in the West, most industrial processes filter much of this soot; not so in the developing world where few emissions controls are in place. Historically, the Industrial Revolution began in the 1700’s before environmental management was understood.

“Black carbon is the strongest sunlight-absorbing atmospheric particle. When these particles settle on the snow blanketing glaciers, they darken the snow surface, speeding its melting and exposing the underlying glacier ice to sunlight and warmer spring and summer air earlier in the year. This diminishing of the snow cover earlier in each year causes the glacier ice to melt faster and retreat.”
Read more

Land Disturbance and Water Diversion

Roger Pielke, Sr. has written and researched a great deal on how our land disturbance and use of water and water diversions have regional effects on climate and biodiversity. Sadly, these aspects of climate change are not considered in the big climate discussions, yet these are factors that are much more within our control and much easier to monitor.

Here’s one of his early papers where the basic argument is described.

Carbon Dioxide and Other Greenhouse Gases

Carbon dioxide constitutes about 4 molecules in 10,000 in our atmosphere. Prof. Emeritus Dick Thones discusses carbon dioxide, its effects and role in the atmosphere in this short brief. In general, it seems the presumed effect of carbon dioxide on warming has been overestimated.

This collection of 5 datasets (the colored lines) show that there is no warming trend after 2002, though there are ups and downs. The blue wavy line shows a dramatic increase in carbon dioxide concentration but there is no warming, The recent warming in 2015 has been due to an El Nino – a known, cyclical atmospheric oscillation that is unrelated to human activity.

A detailed discussion of the many factors affecting climate can be found in this Climate Science Essay.