62 Matching Annotations
  1. Jun 2018
    1. While having a cyclone travel with less speed may seem like a good thing, it's actually just the opposite. Wind speeds within the storm remain high, but the whole system itself moves slower across the landscape, allowing punishing rains to linger longer over communities.

      Another consequence could be to weaken storms while they move over the ocean since slower storms cause greater ocean cooling* and colder surface water decrease hurricanes strength. That would be an interesting hypothesis to test.

  2. Oct 2017
    1. Instrumental temperature measurements over the past 150 years show no correlation between human emissions of CO2 and ­temperature.

      Plotting the relationship between global temperature and the logarithm of atmospheric CO2 concentration shows a strong relationship (Figure below). This is predicted by physics since CO2 is a greenhouse gas. Ian Plimer might confuse CO2 emissions and CO2 concentration in the atmopshere, which is what matters for explaining Earth’s surface temperature.

      Figure - Global temperature from Berkeley Earth’s dataset versus atmospheric CO2 concentrations.

  3. Feb 2017
    1. On top of all of that, declining ocean oxygen can also worsen global warming in a feedback loop. In or near low oxygen areas of the oceans, microorganisms tend to produce nitrous oxide, a greenhouse gas, Gilbert writes.

      Another 'positive feedback loop' related to ocean warming and increased stratification is that this can reduce the ocean CO2 uptake, by preventing CO2 from being mixed down into the deep ocean layers.

    2. But as that upper layer warms up, the oxygen-rich waters are less likely to mix down into cooler layers of the ocean because the warm waters are less dense and do not sink as readily.

      Enhanced stratification of the water column is indeed one mechanism that can explain the decrease in subsurface oxygen, notably in the tropics[1].

      As the upper-layer of the ocean warms faster than the deeper layers, the temperature stratification increases, with the already-warm upper layer getting warmer. This enhanced thermal stratification acts as a barrier to vertical mixing, since warmer water is less dense (like when a low density fluid (eg oil) tops a high density fluid (eg water)). This stratification can prevent oxygen coming from the surface from reaching deeper layers where it gets depleted by biological activity (respiration).

      As climate change proceeds, the upper-ocean layer is also expected to become fresher (less salty) in the tropics as rainfall increase, further increasing the upper-ocean stratification[2].

  4. Jan 2017
    1. First it will kill off all the calcified marine life, such as shellfish, corals and plankton. Then it will destroy all the species that depend on it
  5. Oct 2016
    1. Representatives from the Marshall Islands have been vocal about the need for strong global action on climate. President Hilda Heine has told reporters that longtime residents are leaving the Marshall Islands because climate change is threatening the nation’s existence.

      This is an interesting rhetorical trick by Bjorn Lomborg. So far he has only supported the point that ‘as of today, the area of many Pacific islands have not decreased’. But this doesn’t mean that the islands existence is not threatened, notably in the future as sea level rise becomes more severe. So here, he is swapping a weak claim that he has supported for a much stronger one that he has not, a version of the red herring fallacy.

    2. suggest that residents are fleeing atolls swiftly sinking into the sea. Yet new research shows that this is not the entire—or even an accurate—picture.

      Scientists' comments on this article clearly show that it is also not an "entire" or "accurate" picture. So Mr Lomborg is using the very flawed reasoning he is condemning others of.

  6. Sep 2016
    1. “Although some researchers doubted the existence of a global warming hiatus because of coverage bias, artificial inconsistency, and a change point analysis of instrumental Ts records,” a just-published study at Nature.com’s Scientific Reports found, “it is now accepted that a recent warming deceleration can be clearly observed.”

      This graph of global temperature helps to put the “slowdown” of warming that occurred around the 2000-2010 period in perspective. It is misleading to put the emphasis on the slowdown without reminding that, over the long term, the temperature keeps rising. Source: NOAA

  7. Aug 2016
    1. We have been on an upward trend in terms of heavy rainfall events over the past two decades

      Indeed, there has been an increase in the amount of rain falling during the most extreme events across the eastern and southern US:

      The bar charts show the percent changes in the annual amount of precipitation falling in very heavy events, defined as the heaviest 1% of all daily events from 1901 to 2012 for each region. Adapted from the 2014 National Climate Assessment

    2. The National Weather Service balloon released in New Orleans on Friday showed near-record levels of atmospheric moisture, prompting the service to state: “We are in record territory.”

      This chart from the National Weather Service's Storm Prediction Center shows that the amount of 'Precipitable Water' in the atmosphere over southern Louisiana (Baton Rouge) was unprecedented just before the flood.

    1. The issue now is that these events are even more severe than they otherwise would have been. And they are becoming more frequent in many areas.

      This is indeed observed in the United States. The 2014 National Climate Assessment provides a very detailed analysis of the scientific literature on the subject of heavy downpours increase.

      heavy downpours

  8. May 2016
    1. essentially telling the newspaper to stop reporting less-than-negative climate stories.

      This is a misrepresentation of the Lords' letter. The letter builds on scientists' analyses of 2 inaccurate articles on climate change in The Times, and it asks the editor to center their coverage on the facts rather than on the viewpoints of marginal pressure group.

      Misrepresenting someone's position to make it easier to attack is known as a strawman fallacy.

  9. Feb 2016
    1. Based on extensive geological evidence, scientists already knew that the sea level rose drastically at the end of the last ice age, by almost 400 feet, causing shorelines to retreat up to a hundred miles in places. They also knew that the sea level had basically stabilized, like the rest of the climate, over the past several thousand years, the period when human civilization arose.

      This statement is supported by a recent report in Nature Climate Change written by 22 scientists.

      The figure below shows that global sea level rose by about 100 meters at the end of the last ice age 15 thousand years ago and that sea level had stabilized more than 5 thousand years ago. This helps clear a common misconception that current rate of sea level rise could be simply due to the end of the ice age.

      Sea Level reconstruction

      The last 20,000 and the next 10,000 years of sea level. The vertical scale is measured in meters.

    2. roughly three-quarters of the tidal flood days now occurring in towns along the East Coast would not be happening in the absence of the rise in the sea level caused by human emissions.

      The trend in the number of "coastal flood days" in the US is a convincing supporting evidence of this conclusion.

      increase in coastal flooding

      Visualization created by Climate Central

  10. Jan 2016
    1. El Niño years in a warm plateau usually set a global-temperature record. What happened this year also happened with the last big one, in 1998.

      The author seems to think that the 2015 heat record is no surprise since there was an El Niño event and the same happened in 1998. This is a flawed reasoning: if there were no increase in global temperature, the likelihood of breaking records after records would be very low, it is the underlying upward trend in temperature that makes breaking new records more likely everytime there is a cyclical warming event (El Niño). See this recent article for a quantification of that probability:

      “In summary, our results suggest that the recent record temperature years are roughly 600 to 130,000 times more likely to have occurred under conditions of anthropogenic than in its absence.”

    2. Without El Niño, temperatures in 2015 would have been typical of the post-1998 regime.

      The graph below shows clearly that each of the 3 big El Niños on record (1982, 1997, 2015) are associated with higher global temperatures as time proceeds. Without El Niño, temperatures are higher than in 1998. El Niños source: http://www.columbia.edu/~jeh1/mailings/2016/20160120_Temperature2015.pdf

    3. There are two real concerns about warming,

      This is a rhetorical trick. Who decided that there are only two real concerns? This would assume that the other concerns about climate change are not real? For instance one of the great concern biologists express is the negative impacts on plankton and coral (hence fisheries) of warming and acidification of the ocean due to increased levels of carbon dioxide in the atmosphere see eg:

      This is only one example that there are other concerns about global warming contrary to what the author suggest to readers here.

    1. A warmer atmosphere can hold more water vapor, and an intensification of rainstorms was one of the fundamental predictions made by climate scientists decades ago as a consequence of human emissions. That prediction has come to pass, with the rains growing more intense across every region of the United States, but especially so in the East.

      This is accurate. The 2014 National Climate Assessment provides a detailed analysis of the scientific literature on the subject of intense rainfall events increase in the US.

      heavy downpours

  11. Dec 2015
    1. Sea level continues its centuries-long slow rise—about a foot a century—with no sign of recent acceleration.

      'recent' is not a precise term. On climate relevant scale, evidence shows that sea level rise has been accelerating. See for instance the figure below from Jevrejeva et al

      SLR acceleration

      see also:


      Source: Church (2008) Understanding global sea levels: past, present and future

  12. Nov 2015
    1. based on some theory that’s not proven.

      The candidate misunderstands how science works. Science mostly allows to gain confidence in certain statements, for instance, science allows us to say that it is beyond reasonable doubt that humans are the cause of the current warming of the planet, but it's never going to be proven in the mathematical sense of the term. Nevertheless, probabilistic knowledge is helpful to make decisions: nobody waits until it's proven that their house is going to burn to buy insurance.

    2. But America is not a planet. And we are not even the largest carbon producer anymore, China is

      That's true but, because CO2 remains in the atmosphere for centuries, the US is still the largest contributor to climate change with the largest cumulative emission between 1850 and 2011. 27% of all emissions have been made by the US. cumul emissions source: World Resources Institute

    3. climate change is likely to cause increasingly powerful hurricanes, like Sandy in 2012

      The best available knowledge indeed suggests that the most intense hurricanes are going to become more powerful due to global warming. See eg this synthesis by the Geophysical Fluid Dynamics Laboratory.

      Sandy might not be the best example though as it was a hybrid storm (tropical/extra-tropical), for which the understanding of their response to warming is less well known.

    4. I think nature also has a role

      There is no scientific study showing that natural processes could explain the continued warming we've seen over the past 40 years.

      Read this article in Climate Central for more details:

      nobody has come up with a natural explanation for the current warming episode that fits the observations.

  13. Oct 2015
    1. Severe storms, floods and agricultural losses may cost a great deal of money, but such extreme weather events – and their resulting costs – are dramatically declining as the Earth modestly warms.

      To the best of my knowledge, there is no scientific evidence showing that severe storms and flood are "dramatically declining". Such a strong statement should be supported by a strong reference.

      To the contrary, as the atmosphere warms, water vapor content increases, and this is allowing more extreme rainfall events, notably during hurricanes.

      see eg: Trenberth (2011) Changes in precipitation with climate change

    1. Say No to Climate Change CO2 Coercion at COP-21 Says Friends of Science Society in New Billboard Campaign


    1. These signals showed an "optimal/perfect atmosphere and ocean conditions for explosive intensification," Maue wrote.

      The figure below shows that the "explosive intensification" of the cyclone occurred right above a large anomaly of "Ocean Heat Content". This reinforces the hypothesis that subsurface temperature helped intensification of Hurricane Patricia. OHC source: http://isotherm.rsmas.miami.edu/heat/webp/pacific.php

    2. The ocean warmth is largely due to a near-record strong El Niño event, which has not only raised ocean temperatures in the eastern tropical Pacific, but has also caused those warm waters to extend deeper below the surface than is usually the case, which also helps storms to intensify.

      Indeed, intense winds associated with Hurricanes usually mix the upper-ocean vertically, bringing the cold sub-surface water to the surface, which weakens the cyclone. This mechanism is particularly effective in the East Pacific where the layer of warm water is usually shallow [1].

      El Niño is associated with a deepening of the warm water layer in the East Pacific that allows to sustain much stronger cyclones.

      [1] Vincent et al 2012 Assessing the oceanic control on the amplitude of sea surface cooling induced by tropical cyclones

    1. thanks to sea-level rise due to climate change, flooding is going to get much worse. To put it another way: we don’t need the ocean to rise several meters to create severe floods. The next decade of “normal” hurricanes and tropical storms could bring the effects of climate change right into coastal cities.

      This is indeed supported by the scientific literature. Expected Sea level rise should significantly increase coastal 'extreme water levels'[1] and cause hundreds of billions of $ of damage in the US over the century[2].

      [1] Tebaldi et al 2012 Modelling sea level rise impacts on storm surges along US coasts

      [2] Neumann et al 2014 Joint effects of storm surge and sea-level rise on US Coasts

  14. Sep 2015
    1. The Alaska Climate Research Center reports almost no evidence of warming trends in Alaska since 1977.

      This is likely referring to the 2012 paper by Wendler. In that paper the authors conclude,

      In summary, the long term observed warming of Alaska of about twice the global value, as expected by the increasing CO2 and other trace gases, is sometimes temporarily modified or even reversed by natural decadal variations.

      By "temporarily" the authors were referring to only the first decade of the current century, where Alaska temperatures, like the global average, were influenced by the predominance of La Niña events. The authors clearly do not question anthropogenic global warming.

  15. Aug 2015
    1. helped tamp down hurricanes in the Atlantic Ocean.

      This statement is correct.

      The reduction of Atlantic hurricanes due to El Niño is especially pronounced when the El Niño is associated to warming in the East Pacific[1] (as is the case of the ongoing event); the forecast for this year's hurricane activity is 'well below-average'.

      [1] Kim et al 2009, Science

    1. Daily Telegraph

      The Telegraph (?)

    2. The Guardian

      Climate Feedback has not annotated The Guardian so far. The list is here: http://climatefeedback.org/feedbacks/

    3. Using the Climate Feedback tool,

      Technically, the 'tool' is hypothes.is

      Climate Feedback is an organized group of scientists who are using it

    4. Daily Telegraph

      The Telegraph (?)

    5. The Guardian

      Climate Feedback has not annotated The Guardian so far.

    1. should the oxygen-free layer grow so pronounced that it stratifies, pushing surface ocean warming into overdrive and hindering upwelling of cooler, nutrient-rich deeper water.

      I think there is a confusion here: it is not the oxygen or nutrients concentration in the upper-layer that affects the ocean temperature stratification but the other way around.

      As climate change proceeds, the upper-layer of the ocean –that gets heated from additional infra-red radiation from above due to increased greenhouse effect– warms faster than the deeper layers. It results that the temperature stratification increases, with the already-warm upper layer getting warmer. This enhanced thermal stratification acts as a barrier to vertical mixing, since warmer water is less dense (like when a low density fluid (eg oil) tops a high density fluid (eg water)). This stratification can prevent nutrients from reaching the surface layers from the depth while they get depleted by biological activity in the upper-layer.

      We currently observe an increase of the upper-ocean thermal stratification, especially in the tropics (see eg Behrenfeld et al 2006)

  16. Jul 2015
    1. The earth is 15 years from a "mini ice-age" that will cause bitterly cold winters during which rivers such as the Thames freeze over, scientists have predicted.

      The original press release of the study presents "A new model of the Sun’s solar cycle". It does not mention the influence of the sun on climate nor does it predict a mini ice-age in 15 years. It appears that the Telegraph article has extrapolated the implications of the Sun's activity beyond the original report.

    1. One was the revelation by the European Space Agency that in 2013 and 2014, after years when the volume of Arctic ice had been diminishing, it increased again by as much as 33 per cent.

      In the esa press release, Professor Andrew Shepherd, Director of the Centre for Polar Observation and Modelling reminds:

      Although the jump in volume means that the region is unlikely to be ice free this summer, we still expect temperatures to rise in the future, and so the events of 2013 will have simply wound the clock back a few years on the long-term pattern of decline.

      A simple figure here helps remind the broader context that "the volume of Arctic ice has been steadily falling since the late 1970s"

      Image Description source PIOMAS

    1. the rate of global sea-level rise 70 years ago was as large as what we observe today—about one foot per century

      The rate of sea level rise has actually quadrupled since preindustrial times: the trend was .8 mm/yr from 1870 to 1924, 1.9 mm/yr from 1925 to 1992, and 3.2 mm/yr from 1993 to 2014. sea level rise http://www.columbia.edu/~mhs119/SeaLevel/

  17. Jun 2015
    1. A very solid scientific consensus indicates that we are presently witnessing a disturbing warming of the climatic system.

      Several studies have indeed revealed a large agreement among scientists about the existence and human origin of the Earth's surface warming.

      poll Survey responses to "Do you think human activity is a significant contributing factor in changing mean global temperatures?", from Doran & Zimmerman (2009)

  18. May 2015
    1. New York City would see a local sea level rise of nearly 4 feet by 2100

      For precision, the NCA report mentions a sea level rise of 1 to 4 feet with a high estimation of up to 6 feet by 2100.


      more information can be found in the New York City Panel on Climate Change 2015 Report

  19. Mar 2015
    1. Climate research has shown that tropical cyclones in many ocean basins are becoming stronger and lasting longer than they used to.

      Results by Holland and Bruyere (2013) do show an increase in the proportion of the most intense hurricanes.

      increase in strong TC

      It remains controversial whether these trends are due to anthropogenic climate change alone or are also influenced by data homogeneity issues (eg Landsea et al 2006)

    2. Since sea-level rise is already making cyclones more destructive by giving them a higher launching pad for storm surge flooding,

      This statement is consistent with the analysis by Grinsted et al 2012, for instance, that detects a statistically significant trend in the frequency of large surge events in the Atlantic since 1923.

      This is notable since storm-surge incidence from tropical cyclones are the most damaging aspect of tropical cyclone impacts in coastal region (Knutson et al 2010)

    3. rising sea levels likely made the storm more damaging than it would have been just a few decades ago

      This figure shows that sea level is indeed rising in the Vanuatu region. Part of this recent rise is attributed to anthropogenic climate change and part of it may be attributed to the natural "pacific decadal oscillation" Merrefield et al 2012

      sea level rise

      adapted from Cazeneuve and Remy 2011

    1. people can click on the link and see my (and only my) commentary on the page

      That would be very useful for the Climate Feedback project. Replacing "my" by "our" commentary.

      In our case, replies by others should not be visible by following the direct link (if the purpose is to discourage "trolling")

      Ideally, we would need 2 "kinds of link":

      • One for fellow scientists: following the link invites them to annotate and see the private + public contributions of their peers

      • One for general public: following the link shows the article + public annotations of the group

  20. Feb 2015
    1. much of the data are actually encouraging

      This is a strong claim; a strong reference would be needed to back it up. In this article, the author provides 5 facts about the changing climate to back this assertion. This is far from sufficient to give credit to the author's claim, especially since several of these facts are only one aspect of the story, as shown by the scientists' comments below.

  21. Jan 2015
    1. providing the energy that fueled damaging Pacific storms

      While the east Pacific Tropical Cyclone activity was well above average in 2014 (National Hurricane Center), this is not the case for the west Pacific, which was below average. The argument should be made clearer.

    2. In the annals of climatology, 2014 surpassed 2010 as the warmest year.

      I think the figure below is instructive; It shows that 2014 is more likely than any other year to be the hottest on record. It also shows that the cone of uncertainty for 2014 temperature overlaps the ones for 2005 and 2010. 2014 cannot be said the warmest year with absolute certainty, but it is the most likely. hottest years source: Gavin Schmidt

      In the Berkeley dataset too, 2014 is the warmest year on record but within uncertainty margins with 2010 and 2005.

  22. Dec 2014
    1. It should not be confined to hushed sidebar conversations at academic conferences

      In the Equation, MIT's Pr Emanuel and Pr Solomon comment:

      "This claim amazed us, because uncertainty is a major and perhaps the major focus of scientific research on climate change and on attempts to formulate sensible policy. In the Summary for Policymakers of the latest IPCC Assessment Report, the word uncertain or uncertainty appears 36 times, and graphs pertaining to climate projections have hefty uncertainty limits and error bars. It is hard to claim that uncertainty is being hushed up."

    2. We are very far from the knowledge needed to make good climate policy

      According to MIT's Pr Emanuel and Pr Solomon, the thesis of this article "does not follow from the scientific substance of the essay". Their full argumentation is on The Equation. Here is the extract:

      "Koonin notes several key scientific fundamentals. He does not deny that climate is changing, that human activities are at least partly responsible for it, or that policy formulation should take climate change into account. But the headline statement—that not enough is known about climate to warrant significant action given the risks—is a statement of values and does not follow from the scientific substance of the essay."

  23. Oct 2014
    1. Climate Science Is Not Settled

      Overall scientific quality: 'very poor' to 'poor' (rating 0.5 / 4), according to 6 climate scientists who have evaluated this article.

      evaluation card

      Find more details in the annotations below and at https://docs.google.com/document/d/1OQSqpFUCY_cmgrANshzydOsKCx1P1VQHwbnPTjLjEsc/edit?usp=sharing

    2. These are fundamental challenges to our understanding of human impacts on the climate, and they should not be dismissed with the mantra that "climate science is settled."

      The challenges to understanding human impacts on climate are acknowledged by the scientific community. The author misrepresents the use of the term "settled" that refers to the human origin of climate change. The author here commits a straw-man fallacy as explained here: http://time.com/3445231/climate-denier-settled-science/

    3. The impact today of human activity appears to be comparable to the intrinsic, natural variability of the climate system itself

      There are multiple lines of research showing that the warming signature of human-emitted greenhouse gas increases is much greater than the effects of natural external forcing factors over the last few decades. see for instance Wigley and Santer (2012)

    4. Any serious discussion of the changing climate must begin by acknowledging not only the scientific certainties but also the uncertainties

      This article does not acknowledge the scientific certainties in the domain of climate change science and emphasizes the uncertainties. According to the author's definition, this article would not be qualified "a serious discussion of the changing climate".

    5. That uncertainty need not be an excuse for inaction.

      Incoherent with the main message of the article.

    6. the field is not yet mature enough to usefully answer the difficult and important questions being asked of it.
    7. the carbon dioxide will persist in the atmosphere for several centuries
    8. during the 20th century the Earth's global average surface temperature rose 1.4 degrees Fahrenheit
  24. Sep 2014
  25. Aug 2014
    1. When CO2 dissolves in water, we are NOT adding acid to the water.

      CO2 does increase the acidity when dissolved in water. For reference, see for instance "Once dissolved in seawater, CO2 gas reacts with water to form carbonic acid" in Doney et al (2008) http://www.annualreviews.org/doi/full/10.1146/annurev.marine.010908.163834