Home » Posts tagged 'ZEKE HAUSFACHER'
Tag Archives: ZEKE HAUSFACHER
Analysis: ‘Global’ warming varies greatly depending where you live
As part of the Paris Agreement on climate change, the international community committed in 2015 to limit rising global temperatures to “well below” 2C by the end of the 21st century and to “pursue efforts to limit the temperature increase even further to 1.5C”.
However, these global temperature targets mask a lot of regional variation that occurs as the Earth warms. For example, land warms faster than oceans, high-latitude areas faster than the tropics, and inland areas faster than coastal regions.
Furthermore, global human population is concentrated in specific regions of the planet.
Here, Carbon Brief analyses how much warming people will actually experience where they live, both today and under future warming scenarios.
The warming experienced by people is typically higher than the global average warming. In a world where warming is limited to “well below” 2C about 14% of the population will still experience warming exceeding 2C. In the worst-case scenario of continued growth in emissions, about 44% of the population experiences warming over 5C – and 7% over 6C – in 2100.
Warming is not globally uniform
Different parts of the world respond in different ways to warming from increasing greenhouse gas concentrations. For example, ocean temperatures increase more slowly than land temperatures because the oceans lose more heat by evaporation and they have a larger heat capacity.
High-latitude regions – far north or south of the equator – warm faster than the global average due to positive feedbacks from the retreat of ice and snow. An increased transfer of heat from the tropics to the poles in a warmer world also enhances warming. This phenomenon of more rapidly warming high latitudes is known as polar amplification.
…click on the above link to read the rest of the article…
Analysis: Why scientists think 100% of global warming is due to humans
The extent of the human contribution to modern global warming is a hotly debated topic in political circles, particularly in the US.
During a recent congressional hearing, Rick Perry, the US energy secretary, remarked that “to stand up and say that 100% of global warming is because of human activity, I think on its face, is just indefensible”.
However, the science on the human contribution to modern warming is quite clear. Humans emissions and activities have caused around 100% of the warming observed since 1950, according to the Intergovernmental Panel on Climate Change’s (IPCC) fifth assessment report.
Here Carbon Brief examines how each of the major factors affecting the Earth’s climate would influence temperatures in isolation – and how their combined effects almost perfectly predict long-term changes in the global temperature.
Carbon Brief’s analysis finds that:
- Since 1850, almost all the long-term warming can be explained by greenhouse gas emissions and other human activities.
- If greenhouse gas emissions alone were warming the planet, we would expect to see about a third more warming than has actually occurred. They are offset by cooling from human-produced atmospheric aerosols.
- Aerosols are projected to decline significantly by 2100, bringing total warming from all factors closer to warming from greenhouse gases alone.
- Natural variability in the Earth’s climate is unlikely to play a major role in long-term warming.
Animation by Rosamund Pearce for Carbon Brief. Images via Alamy Stock Photo.
How much warming is caused by humans?
In its 2013 fifth assessment report, the IPCC stated in its summary for policymakers that it is “extremely likely that more than half of the observed increase in global average surface temperature” from 1951 to 2010 was caused by human activity. By “extremely likely”, it meant that there was between a 95% and 100% probability that more than half of modern warming was due to humans.
…click on the above link to read the rest of the article…
Analysis: Global CO2 emissions set to rise 2% in 2017 after three-year ‘plateau’
Over the past three years, global CO2 emissions from fossil fuels have remained relatively flat. However, early estimates from the Global Carbon Project (GCP) using preliminary data suggest that this is likely to change in 2017 with global emissions set to grow by around 2%, albeit with some uncertainties.
Hopes that global emissions had peaked during the past three years were likely premature. However, GCP researchers say that global emissions are unlikely to return to the high growth rates seen during the 2000s. They argue that it is more likely that emissions over the next few years will plateau or only grow slightly, as countries implement their commitments under the Paris Agreement.
2017 emissions likely to increase
The GCP is a group of international researchers who assess both sources and sinks of carbon. It has published an annual global carbon budget report since 2006. Its newly released global carbon budget for 2017 provides estimates of emissions by country, global emissions from land-use changes, atmospheric accumulation of CO2, and absorption of carbon from the atmosphere by the land and oceans.
Video summary of the findings of the GCP’s new 2017 global carbon budget, via Future Earth and the GCP.The figure below shows global CO2 emissions from fossil fuels, divided into emissions from China (red shading), India (yellow), the US (bright blue), EU (dark blue) and the remainder of the world (grey). After a rapid increase in global emissions of around 3% per year between 2000 and 2013, emissions only grew by 0.4% per year between 2013 and 2016.
Annual CO2 emissions from fossil fuels by major country and rest of world from 1959-2017, in gigatons CO2 per year (GtCO2). Note that 2017 numbers are preliminary estimates. Data from the Global Carbon Project and available here. Chart by Carbon Brief using Highcharts.
…click on the above link to read the rest of the article…
State of the climate: 2017 shaping up to be warmest ‘non-El Niño’ year
State of the climate: 2017 shaping up to be warmest ‘non-El Niño’ year
Much of the year, though the summer Arctic minimum was only the eighth lowest on record.
2017 is also almost certain to be the warmest year without an El Niño event. When the effects of El Niño and La Niña are removed from the temperature record, the first nine months of 2017 are likely the warmest ever recorded.
Near-record warm temperatures
Ten months in, 2017 is very likely going to be either the second warmest or third warmest year on record, depending on the temperature series used. While there was some speculation earlier in the year that it could challenge 2016 for first place, colder temperatures in the period from June through September have largely eliminated any chance of a new record.
Carbon Brief has examined global temperature data from eight different climate centres around the world, both for the Earth’s surface and the lower troposphere (TLT). Temperatures for the full year of 2017 were estimated using the data available to-date for each dataset, along with projection of the El Niño Index for the remainder of 2017 (see methods at the end of the article for technical details).
The results are shown in the figure below. Annual temperatures from 1979 through 2016 are shown in black for each record, while the likely (95% confidence interval) range of the 2017 annual temperature is shown by the red bar.
The last two records shown, RSS and UAH, come from satellite data and are measuring the atmosphere on average around 5 km up from the surface. While these have similarities to surface temperatures, they are not expected to always respond in the same way to El Niño or other factors.
…click on the above link to read the rest of the article…
Factcheck: Climate models have not ‘exaggerated’ global warming
Factcheck: Climate models have not ‘exaggerated’ global warming
A new study published in the Nature Geosciences journal this week by largely UK-based climate scientists has led to claims in the media that climate models are “wrong” and have significantly overestimated the observed warming of the planet.
Here Carbon Brief shows why such claims are a misrepresentation of the paper’s main results. In reality, the results obtained from the type of model-observation comparisons performed in the paper depend greatly on the dataset and model outputs used by the authors.
Much of the media coverage surrounding the paper, Millar et al, has focused on the idea that climate models are overestimating observed temperatures by around 0.3C, or nearly 33% of the observed warming since the late 1800s. For example, the Daily Mailreported:
According to these models, temperatures across the world should now be at least 1.3 degrees above the mid-19th century average, which is taken as a base level in such calculations. But the British report demonstrates that the rise is only between 0.9 and 1 degree.
Lead author Dr Richard Millar and his co-authors have pushed back against such media coverage, releasing a statement which says:
A number of media reports have asserted that our [study] indicates that global temperatures are not rising as fast as predicted by the Intergovernmental Panel on Climate Change (IPCC), and hence that action to reduce greenhouse gas emissions is no longer urgent. Both assertions are false. Our results are entirely in line with the IPCC’s 2013 prediction that temperatures in the 2020s would be 0.9-1.3 degrees above pre-industrial [levels].
[Carbon Brief’s guest post by Dr Millar earlier this week includes the paper’s key figures. Additionally, one of his co-authors, Prof Piers Forster, provides further reaction at the end of this article.]
Contrary to media claims, the study found that warming is consistent with the range of IPCC models, albeit a bit lower than the average of all the models.
…click on the above link to read the rest of the article…
