atmosphere Flashcards
describe the nature of the evidence
the body of air that surrounds the planet. most of our atmosphere is located close to the earths surface. where it is most dense. the air is made up of 79% nitrogen and just under 21% oxygen. the remaining amount is composed of CO2 and other gases
describe how data for this type of evidence is collected and analysed
the concentration of the different gases that make up the atmosphere can be directly measured by taking samples at monitoring stations such as the famous Mauna Loa Observatory in Hawaii and at Cape Grimm in Tasmania
what was thr global mean CO2 level in 2021
the global mean C02 levels in 2021 was 417 parts per million (ppm) which is almost 50% increase from pre-industrial (before 1750) concentrations, and most likely the highest level for at least 2 million years
what was the global average atmospheroc concentration of CO2 in 2020
the global average atmospheric concentration of CO2 reached a new record high in 2020 of 412 ppm. in fact the jump of 2.6 ppm in 2020 over 2019 levels, was the fifth-highest annual increase in NOAA’s 63 record
what did carbon subsequently increase to
carbon subsequently increased to 417.5 ppm by the end of 2021, another significant increase of 2.5 ppm
what was the highest recorded atmospheric concentrations of CO2
prior to today, the highest ever recorded atmospheric concentrations of CO2 were 300 ppm occurring over 300,000 years ago
what was the trends in methane gas
similarly, global atmospheric methane (CH4) concentrations is 262 per cent higher, and nitrous oxide (N20) concentrations are 123% higher than in 1750
what do the trends in both these gases show us
both these gases are also at their highest levels for at least 800,000 years
these observed changes in atmospheric temperature and composition provide evidence for climate change in recent human history
what are the potential issues with this source of evidence?
data quality
natural variability
spatial and temporal variability
explain data quality
data quality- there can be errors in the measurements, biases in the data collection methods, or other issues that can affect the quality of the data and the conclusions drawn from it
explain natural variability
natural variability- the earth’s climate has natural cycles of warming and cooling, which can mask or amplify the effects of human-induced climate change
explain spatial and temporal variabilty
spatial and temporal variability- climate change affects different regions of the world differently and changes can occur at different rates and timescales
