Understanding the Science of Climate Models and Climate Change

How to Understand the Global Climate Change Report of May 2014

Many in America find it difficult to accept the science behind the IPCC reports (International Panel on Climate Change) and the indicators summarized in the report below, released by the White House May 2014.  They prefer to believe that Earth undergoes normal cycles of change and that we are just experiencing a “hot” part of a normal cycle.  We should not be worried.

Unfortunately, this is not true. An analogy may help to understand what is going on. A child wakes up, runs downstairs, asks what’s for breakfast, races out of the house to school. To the parents, Everything is “normal”. One day this child hesitates a bit before leaving for school. After a few days of this, the parent concludes that this abnormal behavior indicates something might be wrong; and indeed  finds out later that there is.

In the same way, ice and deep sea floor cores, as well as cores from dying coral reefs  are somewhat like tree rings. Where counting tree rings reveals the tree’s age, the width between rings indicates the rainfall during that year.  In a similar way, these cores reveal the Earth’s breathing of CO2 over thousands of years. For nearly the last 1 million years (http://www.clim-past.net/9/2489/2013/cp-9-2489-2013.html) they reveal the natural variation in Earth’s climate in part because bubbles of air trapped in the cores contain CO2 which can be measured. The way you detect that something may be wrong with a small child, is the same way we detect something abnormal in Earth’s climate. You controlled for all the variations in your child’s behavior so that you detected something unusual when that behavior began to change.  The study of cores for over 1 million years provides the control because we see the variations repeat like clockwork every 15,000 – 40,000 years.  Earth cycles between mini ice ages – cooling – and warming periods where even in the hottest times  Earth never exceeded 350 ppm CO2.  For as far back as the cores have gone, about 1 million years.

When Earth’s normal behavior is accounted for, anything left over-like a child’s unusual behavior- is due to some other factor. Us.

CO2 is now exceeding the “thermal runaway” point of about 400 ppm, a point at the top of an energy hill where a marble now accelerates down the other side and it is impossible to stop.  We pick and choose what to believe at our peril. Conclusions based on science are dispassionate, firmly grounded in principles of physics and chemistry -the same physics that creates the drugs we believe in to cure pain, the cars we drive with confidence and the  smartphones we use.  Assume that rainy weather is forecast with a 70% chance. One finds from looking at weather reports over many many decades, that roughly 7 times out of 10 it in fact did rain on those days it was forecast.   Today, the computer models nearly unanimously are predicting wetter wets and hotter hots.  We ignore the science at our peril  – R. Banos

“Every truth passes through three stages before it is recognized. In the first it is ridiculed, in the second it is violently opposed, in the third it is regarded as self-evident”. -attributed to Shoppenhauer. Or Carl Sagan.

Excerpts of the report are shown below with permission:

Go here for the entire report.

INTRODUCTION

Climate change, once considered an issue for a distant future, has moved firmly into the present. Corn producers in Iowa, oyster growers in Washington State, and maple syrup producers in Vermont are all observing climate-related changes that are outside of recent experience. So, too, are coastal planners in Florida, water managers in the arid Southwest, city dwellers from Phoenix to New York, and Native Peoples on tribal lands from Louisiana to Alaska. This National Climate Assessment concludes that the evidence of human-induced climate change continues to strengthen and that impacts are increasing across the country.

Americans are noticing changes all around them. Summers are longer and hotter, and extended periods of unusual heat last longer than any living American has ever experienced. Winters are generally shorter and warmer. Rain comes in heavier downpours. People are seeing changes in the length and severity of seasonal allergies, the plant varieties that thrive in their gardens, and the kinds of birds they see in any particular month in their neighborhoods.

Other changes are even more dramatic. Residents of some coastal cities see their streets flood more regularly during storms and high tides. Inland cities near large rivers also experience more flooding, especially in the Midwest and Northeast. Insurance rates are rising in some vulnerable locations, and insurance is no longer available in others. Hotter and drier weather and earlier snow melt mean that wildfires in the West start earlier in the spring, last later into the fall, and burn more acreage. In Arctic Alaska, the summer sea ice that once protected the coasts has receded, and autumn storms now cause more erosion, threatening many communities with relocation.

Scientists who study climate change confirm that these observations are consistent with significant changes in Earth’s climatic trends.

Long-term, independent records from weather stations, satellites, ocean buoys, tide gauges, and many other data sources all confirm that our nation, like the rest of the world, is warming. Precipitation patterns are changing, sea level is rising, the oceans are becoming more acidic, and the frequency and intensity of some extreme weather events are increasing. Many lines of independent evidence demonstrate that the rapid warming of the past half-century is due primarily to human activities.

The observed warming and other climatic changes are triggering wide-ranging impacts in every region of our country and throughout our economy. Some of these changes can be beneficial over the short run, such as a longer growing season in some regions and a longer shipping season on the Great Lakes. But many more are detrimental, largely because our society and its infrastructure were designed for the climate that we have had, not the rapidly changing climate we now have and can expect in the future. In addition, climate change does not occur in isolation. Rather, it is superimposed on other stresses, which combine to create new challenges

This National Climate Assessment collects, integrates, and assesses observations and research from around the country, helping us to see what is actually happening and understand what it means for our lives, our livelihoods, and our future. The report includes analyses of impacts on seven sectors – human health, water, energy, transportation, agriculture, forests, and ecosystems – and the interactions among sectors at the national level. The report also assesses key impacts on all U.S. regions: Northeast, Southeast and Caribbean, Midwest, Great Plains, Southwest, Northwest, Alaska, Hawaii and Pacific Islands, as well as the country’s coastal areas, oceans, and marine resources.

Over recent decades, climate science has advanced significantly. Increased scrutiny has led to increased certainty that we are now seeing impacts associated with human-induced climate change. With each passing year, the accumulating evidence further expands our understanding and extends the record of observed trends in temperature, precipitation, sea level, ice mass, and many other variables recorded by a variety of measuring systems and analyzed by independent research groups from around the world. It is notable that as these data records have grown longer and climate models have become more comprehensive, earlier predictions have largely been confirmed. The only real surprises have been that some changes, such as sea level rise and Arctic sea ice decline, have outpaced earlier projections.

What is new over the last decade is that we know with increasing certainty that climate change is happening now. While scientists continue to refine projections of the future, observations unequivocally show that climate is changing and that the warming of the past 50 years is primarily due to human-induced emissions of heat-trapping gases. These emissions come mainly from burning coal, oil, and gas, with additional emissions from other sources.

Global climate is projected to continue to change over this century and beyond, but there is still time to act to limit the amount of change and the extent of damaging impacts.

This report documents the changes already observed and those projected for the future.

Overview

Climate change is already affecting the American people in far-reaching ways. Certain types of extreme weather events with links to climate change have become more frequent and/or intense, including prolonged periods of heat, heavy downpours, and, in some regions, floods and droughts. In addition, warming is causing sea level to rise and glaciers and Arctic sea ice to melt, and oceans are becoming more acidic as they absorb carbon dioxide. These and other aspects of climate change are disrupting people’s lives and damaging some sectors of our economy.

Climate Change: Present and Future

Evidence for climate change abounds, from the top of the atmosphere to the depths of the oceans. Scientists and engineers from around the world have meticulously collected this evidence, using satellites and networks of weather balloons, thermometers, buoys, and other observing systems. Evidence of climate change is also visible in the observed and measured changes in location and behavior of species and functioning of ecosystems. Taken together, this evidence tells an unambiguous story: the planet is warming, and over the last half century, this warming has been driven primarily by human activity.

Ten Indicators of a Warming World Details/Download

Multiple lines of independent evidence confirm that human activities are the primary cause of the global warming of the past 50 years. The burning of coal, oil, and gas, and clearing of forests have increased the concentration of carbon dioxide in the atmosphere by more than 40% since the Industrial Revolution, and it has been known for almost two centuries that this carbon dioxide traps heat. Methane and nitrous oxide emissions from agriculture and other human activities add to the atmospheric burden of heat-trapping gases. Data show that natural factors like the sun and volcanoes cannot have caused the warming observed over the past 50 years. Sensors on satellites have measured the sun’s output with great accuracy and found no overall increase during the past half century. Large volcanic eruptions during this period, such as Mount Pinatubo in 1991, have exerted a short-term cooling influence. In fact, if not for human activities, global climate would actually have cooled slightly over the past 50 years. The pattern of temperature change through the layers of the atmosphere, with warming near the surface and cooling higher up in the stratosphere, further confirms that it is the buildup of heat-trapping gases (also known as “greenhouse gasesâ€) that has caused most of the Earth’s warming over the past half century.

The National Climate Assessment Report, NCA can be found here at the National Climate Assessment Website.