ENVS 224 - HW1 - Homework 1

Chapter 1 – Homework #1

1) Weather and climate differ in:

• Weather is short term, being the state of the atmosphere at a particular place and time. Based on observations that are true by the equipment. Experience and feel every day.

• Climate is long term at a particular location. It can be expressed as averages and extremes. Normal climate is the 30 year average. Averages are changing by period of time. What we can expect in the short run, based on historical data.

2) Where are most weather observations taken?

Thermometer, rain gauges, anemometers, and barometers are mostly located in airports throughout the United States.

3) Based on the Yale University Climate Survey, what is the national % of people who think global warming is happening?

Based on the Yale University Climate Survey, by 2016, 69% of the national population thinks Global Warming is happening. These past years the number has increased to 71%. 4) Define radiative forcing and climate positive and negative feedback.

• Radiative forcing: difference between the sunlight absorbed by the Earth and the energy radiated back to Earth.

• Positive climate feedback: augments changes in climate that result from radiative forcing.

• Negative climate feedback: de-augments changes in climate that result from radiative forcing.

5) Provide an example of climate positive feedback and climate negative feedback.

• Positive feedback: ice melting (mostly sea ice). Being the ice reflective, the part of the energy received by the sun is reflected back to the space. However, when ice melts the soil, water, and vegetation is exposed accumulating more energy.

• Negative feedback: Evaporations. As temperature increases, the levels of evaporation also increase. Thus, creating more clouds that reflect the solar energy back to space, controlling the Earth’s surface temperature.

6) Describe how plate tectonics changed climate (both warmer and cooler) over millions of years.

The movement of plate tectonics have induced to volcanic eruptions. It also leads to a change in the ocean currents, redistributing heat to different places (either cooling or heating). These eruptions increase the levels of CO2 and SO2 leading to a rise in temperature. In the same way, On the other hand, if plate movements are minimal, the temperatures fall. These same plate movements have led to many volcanic eruptions throughout the world that throw into the atmosphere ashes. The ashes in high quantity, limits the sun energy penetration into the Earth, lowering overall temperatures.

7) Describe how volcanic eruptions and El Niño cause climate change. How long do these changes last?

• Volcanic eruption eject a column of ashes ejects dust and gas high into the stratosphere shading radiation and causing temporary cooling. Eruptions also throw many greenhouse gases into the atmosphere also rising temperatures. Volcanoes can induce weather change for as much as five years after the eruption has ended.

• El Niño is a natural climate cycle involving both the atmosphere and oceans. Every three to seven years, warm water that has gradually accumulated to form a deep pool in the eastern Pacific rises to the surface and flows toward the east, bringing drought and soaring temperatures to some areas and torrential rain and floods to others.

8) Why do scientists think climate models are probably pretty good at projecting future climate change?

Climate models are based in the interactions between the atmosphere, oceans ice coverage, surface temperature, etc. Predicting trends based in current and historical data of many factors can increase the reliability of these models.

9) Describe three pieces of evidence that our climate is warming, especially in the past 30 years.

• Average temperatures throughout the Earth are increasing. Thus, leading to severe draughts and wildfires.

• Glaciers are disappearing. More ice is melted than what is added with snowfalls during the winter, reducing glaciers volume.

• Sea levels are rising. As glaciers and permanent ice are melting, new water ends up in the oceans. Aqua-alta scenarios in Venice are becoming more usual.

10) The oceans absorb about 50% of the excess heat in the climate system. T/F?

False.

11) The top ten warmest years in the instrumental record have all occurred in the past 15 years. T/F?

True.

12)Changes in the orbit of the Earth around the sun cause climate changes on the order of decades to centuries. T/F?

True.

13) Scientists refer to man-made climate change as:

Anthropogenic Climate Change.

14) What are the four main reasons the earth’s climate has changed naturally?

1. Moving Continents

2. Orbital (Milankovitch) Cycles

3. Ocean-Atmosphere Interaction

4. Greenhouse Gases

15)What is the one main probable reason for our climate to have changed in an unnatural way since the late 1880s?

Throughout the late 19th century, during the industrial revolution, many factories emerged. The fast growth of the industries caused more greenhouse gases that filled the atmosphere provoking drastic changes in the Earth’s climate.

16) How long does it take for continental drift to cause climate change?

10 millions of years.

17) Milankovitch cycles influence climate over:

Milankovitch cycles are related to the shape of Earth’s orbit and the tilt of Earth’s axis. As orbit changes and the Earth is tilted, the amount of energy is different latitudes and in seasons. While is winter in Chicago is summer in Buenos Aires.

18) Using this link: https://statesummaries.ncics.org/il summarize the Key Messages for the future of the state of Illinois Climate? (hint: There are two messages)

Temperatures in the Illinois State has increased since the beginning of the past Century. In the same way, average temperatures in the state are set to keep increasing this current Century. This rise has led to many factors that are interrelated such as higher evaporation and lake levels fluctuations. Given this temperature increase, Illinois also experiences storms in every season. In the same way, precipitation in the state has been above average over the past two decades. Precipitations are going to be concentrated in the spring and winter seasons, bringing more severe draughts for the summer season. This precipitation shift, may be a risk for spring planting delays.

Save image of the globe you see. How can you use this map to explain to fellow schoolmates about the difference between regional weather patterns (such as the record cold temperatures over the Midwest and Canada) and global temperature conditions? Is the earth still on a long term warming trend?

It is impressive to see temperature anomalies around the globe. While Canada and the US Midwest is experiencing record low temperatures, it is also impressive to see the state of Alaska being 10-20 degrees warmer than usual. The same goes with Northern Greenland and the Artic Sea. It is also important to note that most of South American countries are showing warmer temperatures for this time of the year. In these countries, is included my country Venezuela which is around 5 degrees warmer in almost all of the territory and almost 10 degrees warmer in the Andean area. The earth is definitely going on a long term warming trend as seasons are more extreme and overall temperatures are rising.