Climate Change: Variations in Timing. Across the globe, in response to increases in heat-trapping gases such as carbon dioxide (CO2) in the atmosphere, temperature and precipitation patterns are changing. The rate of climatic change in the next century is expected to be significantly higher than it has been in the past …

State-of-the-art climate models suggest that this will result in an increase of about 3.5oF in global temperatures over the next century. This would be a rate of climate change not seen on the planet for at least the last 10,000 years.

Continued emissions of greenhouse gases will lead to further climate changes. Future changes are expected to include a warmer atmosphere, a warmer and more acidic ocean, higher sea levels, and larger changes in precipitation patterns.

The Short Answer: To predict future climate, scientists use computer programs called climate models to understand how our planet is changing. Climate models work like a laboratory in a computer. They allow scientists to study how different factors interact to influence a region’s climate.

Even if the atmospheric composition of greenhouse gases and other forcing agents was kept constant at levels from the year 2000, global warming would reach about 1.5℃ by the end of the century. Without changing our behaviour it could increase to 3-5℃ by the end of the century.

Despite a small amount of uncertainty, scientists find climate models of the 21st century to be pretty accurate because they are based on well-founded physical principles of earth system processes.

The Short Answer: A seven-day forecast can accurately predict the weather about 80 percent of the time and a five-day forecast can accurately predict the weather approximately 90 percent of the time. Since we can’t collect data from the future, models have to use estimates and assumptions to predict future weather.

The greater Earth’s axial tilt angle, the more extreme our seasons are, as each hemisphere receives more solar radiation during its summer, when the hemisphere is tilted toward the Sun, and less during winter, when it is tilted away.

Models can successfully reproduce important, large-scale features of the present and recent climate, including temperature and rainfall patterns. “Not doing anything about the projected climate change runs the risk that we will experience a catastrophic climate change.

Whether we are talking about traffic noise from a new highway or about climate change or a pandemic, scientists rely on models, which are simplified, mathematical representations of the real world. Models are approximations and omit details, but a good model will robustly output the quantities it was developed for.

Because this tilt changes, the seasons as we know them can become exaggerated. More tilt means more severe seasons—warmer summers and colder winters; less tilt means less severe seasons—cooler summers and milder winters.

The Short Answer: Earth’s tilted axis causes the seasons. Throughout the year, different parts of Earth receive the Sun’s most direct rays. So, when the North Pole tilts toward the Sun, it’s summer in the Northern Hemisphere. And when the South Pole tilts toward the Sun, it’s winter in the Northern Hemisphere.

If the Earth were to stop spinning on its axis, gradually the oceans would migrate towards the poles from the equator. You could travel around the Earth on the equator and stay entirely on dry land—ignoring the freezing cold on the night side, and the searing heat on the day side.

It is known that the Earth’s orbit around the sun changes shape every 100,000 years. The orbit becomes either more round or more elliptical at these intervals. The shape of the orbit is known as its “eccentricity.” A related aspect is the 41,000-year cycle in the tilt of the Earth’s axis.

If the Earth’s tilt were at 10 degrees instead of 23.5 degrees, then the Sun path through the year would stay closer to the equator. So the new tropics would be between 10 degrees north and 10 degrees south, and the Arctic and Antarctic circles would be at 80 degrees north and 80 degrees south.

Earth’s obliquity oscillates between 22.1 and 24.5 degrees on a 41,000-year cycle. Over the course of an orbital period, the obliquity usually does not change considerably, and the orientation of the axis remains the same relative to the background of stars.

It is commonly believed that the Earth is perfectly spherical in shape. But in reality, it is an oblate spheroid, with varied geographies contributing to the uneven distribution of mass on the surface of the Earth. Due to this uneven distribution, Earth wobble as it spins on its axis.

The tilt in Earth’s axis is strongly influenced by the way mass is distributed over the planet. Large amounts of land mass and ice sheets in the Northern Hemisphere make Earth top-heavy. An analogy for obliquity is imagining what would happen if you were to spin a ball with a piece of bubble gum stuck near the top.

23 hours, 56 minutes and 4.0916 seconds

The sun’s vertical rays strike the Tropic of Cancer, 23.5° north of the Equator, during the June solstice. The subsolar point then begins its migration south, and vertical rays strike the Tropic of Capricorn, 23.5° south of the Equator, during the December solstice.

noon

June 21st=highest angle of insolation=highest solar intensity=longest path of sun=sun directly overhead at 23.5 North of equator.

The equator

The places in the world with the fewest daylight hours

• Rjukan (Noruega) Imagine a little village located in a valley to the south of Norway, surrounded by mountains.
• Barrow (USA) We return to North America to visit Barrow, located in the extreme north point of Alaska.
• Tórshavn (Faroe Islands)

The atmosphere radiates heat equivalent to 59 percent of incoming sunlight; the surface radiates only 12 percent. In other words, most solar heating happens at the surface, while most radiative cooling happens in the atmosphere. How does this reshuffling of energy between the surface and atmosphere happen?

the sun

Sources of heat Up to 90% of the Earth’s internal heat originates from radioactive decay. Four radioactive isotopes are responsible for the majority of radiogenic heat because of their enrichment relative to other radioactive isotopes: uranium-238 (238U), uranium-235 (235U), thorium-232 (232Th), and potassium-40 (40K).