CLIMATE MODELS

Climate models are designed to simulate the responses and interaction of the oceans and atmosphere and to account for changes to the land surface, both natural an human induced.

The models predict that the Earth's average surface temperature will rise. Scientist predict the range of LIKELY temperature increase by running many possible future scenarios. However, these predictions are uncertainly because scientist don't know what choices people will make to control greenhouse gasses emission.

There is a variability between models because not only greenhouse gasses affect but also the effect of aerosols, climate feedbacks (snow and ice, water vapour, clouds and carbon cycle) and ocean cycles like El Niño and La Niña have several influence on temperature changes. 

El Niño and La Niña are opposite phases of what is known as the El Niño-Southern Oscillation (ENSO) cycle.La Niña is sometimes referred to as the cold phase (shrot-term cooling influence on global surface temperatures) and El Niño as the warm phase (we expect temperatures to be above the projection). These desviations from normal surface temperatures can have large-scale impacts not only on ocean processes, but also on global weather and climate.

Further information about El Niño y La Niña cycle:
https://www.climate.gov/enso
http://oceanservice.noaa.gov/facts/ninonina.html
http://www.environmentalscience.org/el-nino-la-nina-impact-environment

Finally, climate models are continously progressing and the simulation of important modes of climate variability has increased the overall confidence in the models’ representation of important climate processes.They can simulate the effect of El Niño and Niña effect, xtreme events, cyclones, cloud feedbacks, cryospheric feedbacks and others.

Further information: 

https://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter8.pdf

Links;

http://www.theguardian.com/environment/climate-consensus-97-per-cent/2014/jul/21/realistic-climate-models-accurately-predicted-global-warming
http://www.theguardian.com/environment/climate-consensus-97-per-cent/2014/jul/21/realistic-climate-models-accurately-predicted-global-warming
http://my2050.decc.gov.uk/?shared=true&user=&percent=17&s=22021222221222

CARBON CYCLE

The carbon cycle is the circulation and transformation of carbon back and forth between living things and the environment. Carbon compounds are present in living things like plants and animals and in nonliving things like rocks and soil.

The amount of carbon on the earth and in Earth's atmosphere is fixed, but that fixed amount of carbon is dynamic, always changing into different carbon compounds and moving between living and nonliving things.

Carbon is released to the atmosphere from what are called "carbon sources" and stored in plants, animals, rocks, and water in what are called "carbon sinks."

There are many carbon sources like these;
Plants.
Through photosynthesis plants take carbon dioxide out of the atmosphere and release oxygen.The carbon dioxide is converted into carbon compounds that make up the body of the plant, which are stored in both the parts of the plants like shoots, leaves and roots.

Animals.
Animals eat the plants, breath in the oxygen, and exhale carbon dioxide. The carbon dioxide created by animals is then available for plants to use in photosynthesis. Carbon stored in plants that are not eaten by animals eventually decomposes after the plants die, and is either released into the atmosphere or stored in the soil.

Geologic processes.
Large quantities of carbon can be released to the atmosphere through geologic processes like volcanic eruptions and other natural changes that destabilize carbon sinks. For example, increasing temperatures can cause carbon dioxide to be released from the ocean.

While a portion of the total amount of carbon present on the earth runs through the carbon cycle relatively quickly, another portion of the carbon is caught up in long-lived and stable carbon sinks.

In Earth’s past, the carbon cycle has changed in response to climate change. Variations in Earth’s orbit alter the amount of energy Earth receives from the Sun and leads to a cycle of ice ages and warm periods like Earth’s current climate. Today, changes in the carbon cycle are happening because of people. We perturb the carbon cycle by burning fossil fuels and clearing land. By burning coal, oil, and natural gas, we accelerate the process, releasing vast amounts of carbon (carbon that took millions of years to accumulate) into the atmosphere every year.

Today we can obtain the data of amount of emissions from the World Bank web site. (http://data.worldbank.org/indicator/EN.ATM.CO2E.PC/countries/CN-GB-US-ES?display=graph)

CO2 emissions (kt)

 

CO2 emissions (metric tons per capita)

These graphics show that China is the the largest producer of CO2 and USA is the greatest producer per capita. However, we can observe that the amount of emissions per capita in some counties have steadily declined since 2007, excepting China.

Since the beginning of the Industrial Revolution, when people first started burning fossil fuels, carbon dioxide concentrations in the atmosphere have risen from about 280 parts per million to 387 parts per million.
 
Nowadays human activity has contributed to an atmospheric concentration of carbon dioxide not seen since the Pliocene epoch between 2.6 and 5.3 million years ago.

Sources:
http://www.esrl.noaa.gov/gmd/ccgg/trends/#mlo_full
http://earthobservatory.nasa.gov/Features/CarbonCycle/

SIGNS OF CLIMATE CHANGE - EXTREME EVENTS

How has our climate changed?

In 2013 in March, Spain received more than three times its monthly average precipitation, making it the wettest March since national records began in 1947. Normal precipitation across the country is just 46 millimeters, yet the country received 157 millimeters through the month. Rising rivers threatened many areas with floods.

Source:

https://www.climate.gov/news-features/featured-images/state-climate-extreme-events

The frequency of heavy precipitation has increased over most land areas in Spain, in my opinion this extreme event is related with reaching extrem temperatures that evaporate more water from the oceans.

In the south, Africa suffered droughs however, in the north the spring was unusually cold. Weather is behaving uncommonly everywhere. I would like to emphasise that this year in Ourense, the city where I live, the temperature in winter is higher than previous years and people is concerned about it.

Here other example in 2015,

Extrem weather events seems to be more frequent every year and they are a sign of climate change.

PLIOCENE vs TODAY

On May 9, 2013, carbon dioxide levels in the atmosphere reached the level of 400 parts per million (ppm). The last time the Earth experienced this level of carbon dioxide was in the Pliocene about three to five million years ago. Investigate what the temperatures were during this time period and compare them to today. What could explain the changes?


The last time atmospheric CO2 was at 400ppm, humans didn't exist. It was during the ancient Pliocene era, tree million years ago. If we compare the temperatures in that periode with the tempertatures today, we can observe great diferences:

• In the Piocene the global average temperatures were 3 to 4 ºC warmer than today and the polar temperatures were 10ºC warmer too.
• In the Pliocene the Artic was ice free and the sea level was between 5 and 40 meters higher.

However, the most important diference is that in the Pliocene a higher concentration of CO2 would have been entirely down to natural earth processes. Nowadays, the increase of CO2 levels has been happening much more rapidly today than it did during que Pliocene epoch because of the industrialization, the human activities, burning fosil fuels and other process have changed the amount of greenhouse gases emitted into the atmosphere. Therefore we will progressively continue see climate changes over the next years.



Sources:

http://www.esrl.noaa.gov/gmd/ccgg/trends/weekly.html
https://en.wikipedia.org/wiki/Pliocene
https://scripps.ucsd.edu/programs/keelingcurve/2013/12/03/what-does-400-ppm-look-like/
http://www.skepticalscience.com/pliocene-snapshot.html

DIFFERENCE BETWEEN WEATHER AND CLIMATE

According to the NASA web;

The difference between weather and climate is a measure of time. Weather is what conditions of the atmosphere are over a short period of time, and climate is how the atmosphere "behaves" over relatively long periods of time.

In most places, weather can change from minute-to-minute, hour-to-hour, day-to-day, and season-to-season. Climate, however, is the average of weather over time and space. An easy way to remember the difference is that climate is what you expect, like a very hot summer, and weather is what you get, like a hot day with pop-up thunderstorms.

In Ourense where I live the climate is Oceanic type which is generally characterized by mild temperatures all year round, with maximun in summer and minimun in winter, and also rainfall throughout the year, with a maximun in winter and a minimun in summer.