How do we now

For one such example, see the following article: Mozes, A. USA Today. Many people seem to know things without having a background in sociology. Of course, they may have been trained in other social science disciplines or in the natural sciences, or perhaps they read about findings from scientific research. For example, you would know that electric fences can be pretty dangerous and painful if you touched one while standing in a puddle of water. We all probably have times we can recall when we learned something because we experienced it.

Instead, you would come to know what you believe to be true through informal observation Making observations without any systematic process for observing or assessing accuracy of what is observed. The problem with informal observation is that sometimes it is right, and sometimes it is wrong.

And without any systematic process for observing or assessing the accuracy of our observations, we can never really be sure that our informal observations are accurate. The fact that one man happened to lie to her in one instance came to represent all experiences with all men.

But do all men really lie all the time? Probably not. This friend committed what social scientists refer to as selective observation Noticing only patterns that one has experienced directly or wishes to find. Mikkelson, B. Her mother was the authority, after all. Without questioning what we think we know to be true, we may wind up believing things that are actually false. This is most likely to occur when an authority A socially defined source of knowledge.

The definition for authority provided here comes from the following source: Adler, E. Belmont, CA: Wadsworth. The rise of humans about 2. Paleontologists rely on radiometric dating to determine the ages of fossils, such as this million-year-old trilobite, Ameura major , from near Kansas City, Kansas.

Photo courtesy Hazen Collection, Smithsonian Institution. The oldest known rocks, including basalt and other igneous formations, solidified from incandescent red-hot melts.

These durable samples from the moon and meteorites are typically poor in potassium, but fortunately, they incorporate small amounts of uranium and other radioactive isotopes. As soon as these molten rocks cool and harden, their radioactive elements are locked into place and begin to decay.

The most ancient of these samples are several types of meteorites, in which slightly more than half of the original uranium has decayed to lead. These primordial space rocks, the leftovers from the formation of Earth and other planets, yield an age of about 4. The oldest known moon rocks, at about 4. Only a few uranium-rich, sand-sized grains of the hardy mineral zircon, some as old as 4.

Nevertheless, uranium-bearing rocks, on every continent provide a detailed chronology of the early Earth Hazen et al. The oldest Earth rocks, at about four billion years, point to the early origins of continents. Rocks from almost 3. Distinctive uranium-rich sedimentary formations and layered deposits of iron oxides from about 2. Indeed, every stage of Earth history has been dated with exquisite accuracy and precision thanks to radiometric techniques. Stromatolites, such as this 2.

Radiometric methods provide an accurate approach to dating such ancient sediments. Photo courtesy of Dominic Papineau.

Overwhelming observational evidence confirms that Earth history is the story of the co-evolving geospheres and biospheres: Life has changed continuously over the course of Earth history. As the work of Eugenie Scott has so forcefully defended, Earth must be billions of years old Scott However, such a conclusion is at odds with the doctrine of many Christian fundamentalists, who believe in the literal Biblical chronology of a universe no more than about 10, years old.

How can science respond to such adamant claims? The testimony of the rocks is unambiguous: an enormous body of observational evidence points to the reality of deep time. Annual ice and rock layerings reveal a million years of Earth history.

Geologic rates of mountain building, erosion and plate tectonics demand hundreds of millions of years. Radiometric dating pushes the history back billions of years. And when these techniques overlap, their independent estimates of the timing of ancient events are internally consistent. And then, remarkably, he proceeds to describe how God created everything 10, years ago to look much older!

But, no, according to the doctrine of created antiquity, the universe was created with light from those stars and galaxies already on its way to Earth. We observe rocks with characteristic ancient ratios of radioactive and daughter isotopes. Presumably, the rocks are ancient. But no, those rocks were created with just the right mixtures of uranium, lead, potassium, and carbon to make them appear much older than they really are. Here, scientists are stymied. It is difficult to imagine any experiment or observation that could disprove the doctrine of created antiquity.

I refuse to accept the idea that any God would bestow such precious gifts as our senses and reason, seemingly to understand His creation, and then try to fool us.

Every scientific idea must be testable by observations or experiments that can be independently confirmed. In principle, it must be possible to imagine outcomes that would prove the proposition wrong.

Without such independent confirmation, a hypothesis cannot be considered scientific. Created antiquity is not falsifiable. Consequently, the teaching of young-Earth creationism, as well as any other doctrine based on a miraculous creation of life, has been repeatedly prohibited in public schools not because the doctrine was proved wrong, but because it simply is not science.

Aguillard , creationism is a religious belief that is inherently untestable by the techniques of science Working Group on Teaching Evolution Many lines of evidence point to the unfathomable antiquity of Earth.

More than a dozen other techniques also provide reliable age determinations: fission-track dating based on gradual accumulation of radiation damage, thermochronology based on the slow diffusion of atoms through rocks, methods that rely on surface weathering rates or even on the slow growth of lichens. These and other measures of deep time are independent yet yield the same unassailable results. Geologic data are complemented by insights from astrophysics see Krauss this issue and biology see Padian this issue.

The lessons of the rocks, stars, and life are equally clear. If you would choose to understand Earth then you must divorce yourself from the inconsequential temporal or spatial scale of a human life. We live on a single tiny world in a cosmos of a hundred billion galaxies, each with a hundred billion stars. Similarly, we live day by day in a cosmos aged hundreds of billions of days. If you would seek for meaning and purpose in the cosmos, you will not find it in any privileged status in space or time.

Rather, Earth and the heavens declare the glory of a cosmos bounded by natural laws that lead inevitably, inexorably to a universe that is learning to know itself.

Dalrymple GB. The age of the earth. Stanford: Stanford University Press; Google Scholar. Dickin AP. Radiogenic isotope geology. Science Explorer. Multimedia Gallery. Park Passes. Technical Announcements. Employees in the News. Emergency Management. Survey Manual. The scientific community is certain that the Earth's climate is changing because of the trends that we see in the instrumented climate record and the changes that have been observed in physical and biological systems.

The instrumental record of climate change is derived from thousands of temperature and precipitation recording stations around the world. We have very high confidence in these records as a whole. The evidence of a warming trend over the past century is unequivocal. Many types of instrumental records point to a climate warming trend. Our streamflow records show an earlier peak in spring runoff; borehole temperature records in Alaskan permafrost as well as water temperature records on land and sea show the warming trend.

The physical and biological changes that confirm climate warming include the rate of retreat in glaciers around the world, the intensification of rainfall events, changes in the timing of the leafing out of plants and the arrival of spring migrant birds, and the shifting of the range of some species. Landsat surface temperature and land cover products have been used to estimate surface temperatures in urban and surrounding nonurban areas and to quantify urban heat island intensity.

Understanding the intensity and long-term temporal trends of urban heat islands enables the heat-related health challenges associated with heat waves to be This report provides an overview of model-based climate science in a risk management context.

In addition, it summarizes how the U. Geological Survey USGS will continue to follow best scientific practices and when and how the results of this research will be delivered to the U. Department of the Interior DOI and other stakeholders to A Record of Change - Science and Elder Observations on the Navajo Nation is a minute documentary about combining observations from Navajo elders with conventional science to determine how tribal lands and culture are affected by climate change.

On the Navajo Nation, there is a shortage of historical climate data, making it difficult to assess Two recent investigations of climate-change vulnerability for 19 terrestrial, aquatic, riparian, and coastal ecosystems of the southeastern United States have identified a number of important considerations, including potential for changes in hydrology, disturbance regimes, and interspecies interactions.

Complementary approaches using geospatial Scientists from the U. Geological Survey USGS are finding evidence of a much wetter past in the deserts of the American Southwest using a most unlikely source—wetlands. Wetlands form in arid environments where water tables approach or breach the ground surface. Often thought of as stagnant and unchanging, new evidence suggests that Geological Survey USGS informs key resource management decisions for Arctic Alaska by providing scientific information on current and future ecosystem response to a warming climate.

The United States is one of eight Arctic nations responsible for the stewardship of a polar region undergoing dramatic environmental, social, and economic changes. Although warming and cooling cycles have occurred over millennia in the Arctic region, the current warming trend is unlike anything recorded previously and is affecting the region The BCM is a fine-scale hydrologic model that uses detailed maps of soils, geology, topography, and transient monthly or daily maps of potential evapotranspiration, air temperature, and precipitation to generate maps of recharge, runoff, snow pack, actual evapotranspiration, and climatic water deficit.

With these comprehensive environmental inputs The U. Geological Survey USGS Changing Arctic Ecosystems CAE initiative strives to inform key resource management decisions for Arctic Alaska by providing scientific information and forecasts for current and future ecosystem response to a warming climate.

Remote sensing of land-surface phenology is an important method for studying the patterns of plant and animal growth cycles.

Phenological events are sensitive to climate variation; therefore phenology data provide important baseline information documenting trends in ecology and detecting the impacts of climate change on multiple scales. The USGS Executive SummaryThe U. The Arctic Coastal Plain of northern Alaska is a complex landscape of lakes, streams, and wetlands scattered across low relief tundra that is underlain by permafrost. This region of the Arctic has experienced a warming trend over the past three decades, leading to thawing of on-shore permafrost and the disappearance of sea ice at an unprecedented A new study led by the U.

Can indigenous knowledge of the local environment help inform climate science? If so, then what is the best way for climate scientists and tribal members to share what they know? New research from the U. Geological Survey and partners illustrates how climate change is perceived among different generations of indigenous residents in subarctic Alaska. In , Eunice Foote discovered that blanket, showing that carbon dioxide and water vapor in Earth's atmosphere trap escaping infrared heat radiation.

In the s, physicist John Tyndall recognized Earth's natural greenhouse effect and suggested that slight changes in the atmospheric composition could bring about climatic variations. In , a seminal paper by Swedish scientist Svante Arrhenius first predicted that changes in atmospheric carbon dioxide levels could substantially alter the surface temperature through the greenhouse effect. Levitus, S. NCEI ocean heat content, temperature anomalies, salinity anomalies, thermosteric sea level anomalies, halosteric sea level anomalies, and total steric sea level anomalies from to present calculated from in situ oceanographic subsurface profile data NCEI Accession Version 4.

Heat stored in the Earth system: where does the energy go? Velicogna, I. National Snow and Ice Data Center. Robinson, D. Hall, and T. Boulder, Colorado USA. Fahey, K. Hibbard, D. Dokken, B. Stewart, and T. Maycock eds. Sabine et. An indicator of current global average temperature as measured by NASA; updated annually. Global Climate Change: Causes.

An overview of the greenhouse effect and other contributors to abrupt climate change.