CUESTIONARIO CIENCIAS I PROYECTO CON RESPUESTAS

CUESTIONARIO CON RESPUESTAS (Sólo redáctalo y tradúcelo en tu bitácora)

1. Los gases de efecto invernadero son un proceso natural en la atmósfera que tiene un tremendo impacto sobre la tierra. Describe este proceso, incluye lo que lo causa, los factores que influyen en él y cómo este afecta a la tierra.
energy (heat) is reradiated to the atmosphere. Greenhouse gases absorb this energy, thereby allowing less heat to escape back to space, and 'trapping' it in the lower atmosphere. Many greenhouse gases occur naturally in the atmosphere, such as carbon dioxide, methane, water vapor, and nitrous oxide, while others are synthetic. Those that are man-made include the chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs) and Perfluorocarbons (PFCs), as well as sulfur hexafluoride (SF6)
Actually, the panel concluded that it was at least 90% certain that human emissions of greenhouse gases rather than natural variations are warming the planet's surface
Global warming is the result of heat absorption by certain gases in the atmosphere (called greenhouse gases because they effectively 'trap' heat in the lower atmosphere) and re-radiation downward of some of that heat. Water vapor is the most abundant greenhouse gas, followed by carbon dioxide and other trace gases. Without a natural greenhouse effect, the temperature of the Earth would be about zero degrees F (-18°C) instead of its present 57°F (14°C).
human activities are leading to an enhancement of the greenhouse effect by the emission of greenhouse gases through fossil fuel combustion and deforestation.
An enhanced greenhouse effect is expected to cause cooling in higher parts of the atmosphere because the increased "blanketing" effect in the lower atmosphere holds in more heat, allowing less to reach the upper atmosphere


2. Identifica el mayor de los gases de efecto invernadero encontrado en la atmósfera.
Water Vapor is the most abundant greenhouse gas in the atmosphere, which is why it is addressed here first. However, changes in its conentration is also considered to be a result of climate feedbacks related to the warming of the atmosphere rather than a direct result of industrialization

3. Mientras que el término gases de efecto invernadero tiene una connotación negativa cuando es usado generalmente, el proceso es crucial para la vida en la tierra. Explica por qué.
Without a natural greenhouse effect, the temperature of the Earth would be about zero degrees F (-18°C) instead of its present 57°F (14°C).

4. Compara los niveles de CO2 antes del inicio de la edad industrial en la mitad de 1700 y posterior en el 2004.
Otro hallazgo es la concentración de dióxido de carbono en la atmósfera, que era de 220 partes por millón (ppm) en las eras de hielo y de 280 ppm en los períodos interglaciales. Desde 1750, la proporción de dióxido de carbono, un gas de efecto invernadero, subió a 370 ppm por la actividad humana. Este es el valor más alto de los últimos 500.000 años.


5. Los cambios en la concentración de los gases de efecto invernadero pueden causar cambios a largo plazo en el promedio de de la temperatura de la superficie. ¿Qué otros factores naturales o eventos pueden también causar cambios a largo término sobre esa temperatura?
changes in the number and size of volcanic eruptions or an increase in the sun's output (such phenomena are referred to as climate forcings), are responsible
Since our entire climate system is fundamentally driven by energy from the sun, it stands to reason that if the sun's energy output were to change, then so would the climate.
In addition to changes in energy from the sun itself, the Earth's position and orientation relative to the sun (our orbit) also varies slightly, thereby bringing us closer and further away from the sun in predictable cycles (called Milankovitch cycles). Variations in these cycles are believed to be the cause of Earth's ice-ages (glacials).
Las precipitaciones pluviales, el aumento o disminución de formación de nubes, el cambio en las corrientes de agua y aire

6. La composición de la atmósfera y las condiciones de ésta son diferentes hoy que en otros tiempo de la historia de la tierra. ¿Qué tipos de cosas hacen los científicos para aprender y examinar lo que sucedió en la atmósfera hace miles o incluso cientos de miles de años? Específicamente, explica como la historia del clima puede ser reconstruida desde un casquete polar.
Paleoclimatic data are critical for enabling us to extend our knowledge of climatic variability beyond what is measured by modern instruments. Many natural phenomena are climate dependent
Some useful paleoclimate data can be found in sources as diverse as tree rings, ice cores, corals, lake sediments (including fossil insects and pollen data), speleothems (stalactites etc), and ocean sediments.
Ice core data suggest that the 20th century has been warm in many parts of the globe, but also that the significance of the warming varies geographically, when viewed in the context of climate variations of the last millennium.
By looking at layers of snow and ice in glacial ice cores, and the gases trapped inside, we can analyze thousands of years of climate change. And, these snapshots of climate history shows us how quickly climate can change
How can a history of climate be reconstructed from an ice core? When snow falls it carries with it the compounds that are in the air at the time, compounds ranging from sulfate, nitrate and other ions, to dust, radioactive fallout, and trace metals. When snow falls in a place where temperatures above freezing are rare (there is only a hint of any melting at the GISP2 site in the 750 year record recovered to date), such as in polar regions or at high altitude, the snow from one year falls on top of the previous year without melting.
As each yearÕs snowfall is buried by successive years' snowfall, the constituents contained in the snow are buried along with it. By drilling down from the surface of an ice sheet and analyzing snow from greater and greater depths, a history of the compounds in the air can be obtained. Further, snow that is deeper than 80 meters at the GISP2 site turns into ice from the weight of the snow above it, and trapped in the ice are small bubbles of air. Thus, in addition to trapping compounds from the air, an ice sheet traps a small sample of the air itself. This trapped air is also analyzed and provides information about the composition of the atmosphere at the time the ice formed.
Like ice cores, deep sea cores have also provided information about climate, but from accumulated sediments on the ocean floor. Unlike ice cores, which provide direct climate information, sediment cores provide indirect information. An example of this indirect evidence is the method for determining temperature. When sediment cores are analyzed researchers painstakingly sort out plankton shells which twist in different directions depending on the temperature of the water they grew in. By counting the number of shells that twist each way the temperature of the surface water at the time that they grew can be determined. Understanding the behavior of these plankton in the modern world is necessary to produce a historical record of temperature for the ocean.


7. Los análisis de concentraciones de gases en el hielo de los glaciares muestran un abrupto cambio climático que tuvo lugar hace 12,000 años. A este periodo se le denominó Younger Dryas y ha cambiado el pensamiento de los científicos acerca del tiempo requerido para un cambio climático global. Describe este periodo, incluyendo como pudo estar relacionado en el pasado con el calentamiento global para que se sucediera.
An example of an extremely quick climate change came during a period of time known as the Younger Dryas, which happened right after the last ice age ended, about 12,000 years ago. The Younger Dryas itself lasted about 1,000 years. What we didn't know until recently was just how quickly the Younger Dryas started and stopped. In a period of less than 50 years, the climate from the eastern US and Canada to much of Europe went from climate conditions much like today's, to frigid readings more like the Ice Age, at least a ten degree Farenheit change. That's how it stayed for a thousand years - and then the climate flipped back to normal in as little as 20 years.
As the Ice Age glaciers dissolved across North America, their meltwater poured into the Atlantic. Some researchers think this meltwater pinched off the warm Gulf Stream, allowing the water to cool down dramatically in the northern Atlantic Ocean. Could this happen in our lifetime? Well, it could, and ironically it could because of global warming. If global warming causes heavier rain, and more water is being dumped into the North Atlantic, it could flip the climate switch just like that and changes hot or cold would occur around the world in a climatological blink of an eye.