This area of Lakeport, California was flooded due to extreme weather during the 1998 El Niño event. El Niño causes changes in rainfall patterns around the world.
Click on image for full size
Courtesy of FEMA
El Niño and Other Climate Events
Sometimes there is a disruption in Earth’s climate system that might last a few weeks or a few months or a year or more. During these events, the air in part of the atmosphere changes the way it circulates for a while. Often there are changes in the ocean too. These changes disrupt the normal patterns of weather in many areas. Weather conditions return to their normal patterns when the atmosphere and ocean circulation returns to its normal pattern.
These disruptions in the atmosphere and ocean can cause changes in the weather both in the area of the disruption and far from it. Changes in the atmosphere in one place that affect weather far away are called teleconnection patterns. Scientists are trying to sort out how this works so that they can better understand and predict weather patterns worldwide.
There are several different patterns of disruptions that happen in the atmosphere and oceans. The largest are described below. These events are natural parts of the Earth’s climate; however they might be changing due to global warming.
The El Niño-Southern Oscillation (ENSO) is the strongest natural fluctuation in climate. It is a disruption of the ocean-atmosphere system in the tropical Pacific that causes changes to weather and climate in places around the globe. Both phases of ENSO – El Niño and La Niña – can cause changes in weather including intense rainstorms, drought, and a change in the amount of storms.
Changes in the North Atlantic Oscillation (NAO) cause variability in Northern Hemisphere winter conditions like the amount of snow and cold temperatures. The NAO is closely related to the Arctic Oscillation and is also affected by ENSO.
Last modified September 4, 2008 by Lisa Gardiner.
Shop Windows to the Universe Science Store!
The Winter 2009 issue of The Earth Scientist
, focuses on Earth System science, including articles on student inquiry, differentiated instruction, geomorphic concepts, the rock cycle, and much more!
You might also be interested in:
Climate in your place on the globe is called regional climate. It is the average weather pattern in a place over more than thirty years, including the variations in seasons. To describe the regional climate...more
Changes in the atmosphere in one area of the world can affect weather over 1000 miles away. Scientists are trying to sort out these relationships, called teleconnections, to better understand and predict...more
Earth’s climate is warming. During the 20th Century Earth’s average temperature rose 0.6° Celsius (1.1°F). Scientists are finding that the change in temperature has been causing other aspects of our planet...more
Each year scientists make predictions about the strength of the upcoming hurricane season. To make seasonal hurricane predictions, scientists look at climate models and climate events that are known to...more
Earth is a complex system of interacting rock, water, air, and life. Big Idea 3.1 The four major systems of Earth are the geosphere, hydrosphere, atmosphere, and biosphere. The geosphere includes a metallic...more
Looking for online content that can be used for a climate change education course or module? Pages linked below can be used to support an introductory climate change education for either a unit or a full...more
Leaders from 192 nations of the world are trying to make an agreement about how to limit emissions of heat-trapping greenhouse gases, mitigate climate change, and adapt to changing environmental conditions....more