Ppm koldioxid i atmosfären
Koldioxidförändringarna Grafen visar variation över årstiderna och skillnaden mellan norra och södra hemisfärerna. Koldioxid i jordens atmosfär förekommer i en relativt låg koncentration, ungefär ppm, men har stor betydelse för temperatur och växtlighet på jorden. In Earth's atmosphere , carbon dioxide is a trace gas that plays an integral part in the greenhouse effect , carbon cycle , photosynthesis and oceanic carbon cycle.
It is one of three main greenhouse gases in the atmosphere of Earth. As of March , the monthly average concentration of CO 2 reached a new record high of By the latest measurement, levels had further escalated to Carbon dioxide is a greenhouse gas. It absorbs and emits infrared radiation at its two infrared-active vibrational frequencies.
Varför går koldioxidhalten i atmosfären upp och ner?
The two wavelengths are 4. CO 2 plays a significant role in influencing Earth 's surface temperature through the greenhouse effect. Absorption of infrared light at the vibrational frequencies of atmospheric CO 2 traps energy near the surface, warming the surface of Earth and its lower atmosphere. Less energy reaches the upper atmosphere, which is therefore cooler because of this absorption. The increase in atmospheric concentrations of CO 2 and other long-lived greenhouse gases such as methane increase the absorption and emission of infrared radiation by the atmosphere.
This has led to a rise in average global temperature and ocean acidification. Another direct effect is the CO 2 fertilization effect. The increase in atmospheric concentrations of CO 2 causes a range of further effects of climate change on the environment and human living conditions.
Startsida - Nyheter
The present atmospheric concentration of CO 2 is the highest for 14 million years. Since the start of the Industrial Revolution , atmospheric CO 2 concentration have been increasing, causing global warming and ocean acidification. Each part per million of CO 2 in the atmosphere represents approximately 2. It was pointed out in that "the current rates of increase of the concentration of the major greenhouse gases carbon dioxide, methane and nitrous oxide are unprecedented over at least the last , years".
Around the emission rate was over 40 gigatons per year. Atmospheric CO 2 concentrations fluctuate slightly with the seasons, falling during the Northern Hemisphere spring and summer as plants consume the gas and rising during northern autumn and winter as plants go dormant or die and decay. The level drops by about 6 or 7 ppm about 50 Gt from May to September during the Northern Hemisphere's growing season, and then goes up by about 8 or 9 ppm.
The Northern Hemisphere dominates the annual cycle of CO 2 concentration because it has much greater land area and plant biomass in mid-latitudes degrees than the Southern Hemisphere. Concentrations reach a peak in May as the Northern Hemisphere spring greenup begins, and decline to a minimum in October, near the end of the growing season. Concentrations also vary on a regional basis, most strongly near the ground with much smaller variations aloft.
In urban areas concentrations are generally higher [ 24 ] and indoors they can reach 10 times background levels. The concentrations of carbon dioxide in the atmosphere are expressed as parts per million by volume abbreviated as ppmv, or ppm v , or just ppm. To convert from the usual ppmv units to ppm mass abbreviated as ppmm, or ppm m , multiply by the ratio of the molar mass of CO 2 to that of air, i. The first reproducibly accurate measurements of atmospheric CO 2 were from flask sample measurements made by Dave Keeling at Caltech in the s.
Additionally, measurements are also made at many other sites around the world. Many measurement sites are part of larger global networks. Global network data are often made publicly available. From these measurements, further products are made which integrate data from the various sources. These products also address issues such as data discontinuity and sparseness. While CO 2 absorption and release is always happening as a result of natural processes, the recent rise in CO 2 levels in the atmosphere is known to be mainly due to human anthropogenic activity.
The extraction and burning of fossil fuels, releasing carbon that has been underground for many millions of years, has increased the atmospheric concentration of CO 2. Burning fossil fuels such as coal , petroleum , and natural gas is the leading cause of increased anthropogenic CO 2 ; deforestation is the second major cause. In , 9. The global average energy-related carbon footprint is around 4. On Earth, carbon dioxide is the most relevant, direct greenhouse gas that is influenced by human activities.
Carbon dioxide is often mentioned in the context of its increased influence as a greenhouse gas since the pre-industrial era. In , the increase in CO 2 was estimated to be responsible for 1. Earth's natural greenhouse effect makes life as we know it possible, and carbon dioxide in the atmosphere plays a significant role in providing for the relatively high temperature on Earth. The greenhouse effect is a process by which thermal radiation from a planetary atmosphere warms the planet's surface beyond the temperature it would have in the absence of its atmosphere.
The concept of more atmospheric CO 2 increasing ground temperature was first published by Svante Arrhenius in The increased forcing drives further changes in Earth's energy balance and, over the longer term, in Earth's climate.