It is settled science. The globe is warming.

The question has been how much did we contribute. But that is now become quantifiable, and we have contributed to this warming.

You believe what you want. I believe in science...


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QOP = Terrorists
FK = Gay

This is my OWN work based on an interview I did a while back:

Summary

- Man is impacting the climate and it is measurable (as noted in the official NCDC statement)
- Man's impact on tropical cyclones is not yet detectable, but we may be having an impact (from official GFDL statement)
- Frequency of global tropical cyclones may decrease due to warming (Increased vertical shear, warmer upper atmosphere temperatures)
- The intensity of global tropical cyclones is expected to increase (larger sensible/latent heat fluxes)
- Rainfall from global tropical cyclone is expected to increase (more available moisture)

NCDC - https://www.ncdc.noaa.gov/monitoring-references/faq/indicators.php

GFDL - https://www.gfdl.noaa.gov/global-warming-and-hurricanes/

AMS - https://www.ametsoc.org/ams/index.cfm/about-ams/ams-statements/statements-of-the-ams-in-force/climate-change/

1) Has the ferocity and frequency of tropical cyclones increased in real terms in recent
years as some commentators suggest they may have?

Some studies have shown a pronounced upward trend in frequency of storms. However we have to consider that observations were very limited in the pre satellite era and we mainly relied on ships to identify tropical cyclones. The NOAA Geophysical Fluid Dynamics Laboratory (GFDL) found after adjusting for this, there has only been a very small increase in tropical cyclones. Chris Landsea, Science and Operations officer at the National Hurricane Center, found in 2010 that the rising trend in tropical cyclones is due almost entirely to short durations storms.

Using Accumulated Cyclone Energy (ACE), which is a measure that quantifies a storms strength and duration, as a metric for activity - 5 of the top ten seasons of ACE in the Atlantic since 1851 have occurred between 1995 and 2017. (Need EPAC, WPAC, and IO/SA

2) In your own opinion, are we really having an unequivocal effect on
climate change and is it getting worse due to our our actions? And, if
so, how might it worsen in the coming years if we can't bring it under
control?

There are many things at work in a complicated global feedback cycle, but yes I am aligned with the American Meteorological Society and NCDC statements. The evidence shows that we are having an impact on climate change.

The US National Climate Date Center (NCDC) says explicitly - 'A large body of evidence supports the conclusion that human activity is the primary driver of recent warming. This evidence has accumulated over several decades, and from hundreds of studies. The first line of evidence is our basic physical understanding of how greenhouse gases trap heat, how the climate system responds to increases in greenhouse gases, and how other human and natural factors influence climate. The second line of evidence is from indirect estimates of climate changes over the last 1,000 to 2,000 years. These estimates are often obtained from living things and their remains (like tree rings and corals) which provide a natural archive of climate variations. These indicators show that the recent temperature rise is clearly unusual in at least the last 1,000 years. The third line of evidence is based on comparisons of actual climate with computer models of how we expect climate to behave under certain human influences. For example, when climate models are run with historical increases in greenhouse gases, they show gradual warming of the Earth and ocean surface, increases in ocean heat content, a rise in global sea level, and general retreat of sea ice and snow cover. These and other aspects of modeled climate change are in agreement with observations.'

NOAA GFDL also sums this up nicely with respect to tropical cyclones - 'It is premature to conclude that human activities - and particularly greenhouse gas emissions that cause global warming - have already had a detectable impact on Atlantic hurricane or global tropical cyclone activity. That said, human activities may have already caused changes that are not yet detectable due to the small magnitude of the changes or observational limitations, or are not yet confidently modeled (e.g., aerosol effects on regional climate).'

3) If you're of the view that the spate of powerful Atlantic hurricanes in 2017
wasn't exacerbated by man's effects on the environment then what do you
think might have caused it?

This year we did have cooler than normal sea surface temperatures develop over the eastern Pacific. While this was not classified as a La Nina event which is directly correlated with busier Atlantic hurricane seasons, there was likely some impact from this by lessening storm killing vertical wind shear over the Caribbean/Atlantic basin. Also we have been in an active phase of the Atlantic Multidecadal Oscillation (AMO). This is is a 20-30 year period of enhanced Atlantic tropical cyclone activity that began in 1995. This is followed by a s 20-30 year period of quieter activity. It will be interesting to see how the Atlantic tropical seasons pan out in the future when we enter the less active AMO phase.

4) Climate change is such a contentious issue, and particularly in the
US. If climate change as a result of global warming really is having an
impact on our weather systems then how would it manifest itself during
hurricane season?

Yes this is a contentious issue. In relation to tropical cyclones, warmer air temperatures allows the air to hold more water. The conversion of water vapor to a liquid releases large amounts of heat and this is the main driver of tropical cyclone intensity. So the increase in available moisture content due to warming air temperatures means there is more latent heat available to fuel tropical cyclones which can lead to stronger storms. Also, more available water vapor also leads to higher rainfall rates.

Therefore in a warming world, we should expect more intense storms. In fact the NOAA GFDL says 'There are better than even odds that anthropogenic warming over the next century will lead to an increase in the occurrence of very intense tropical cyclone in some basins - an increase that would be substantially larger in percentage terms than the 2-11% increase in the average storm intensity. This increase in intense storm occurrence is projected despite a likely decrease (or little change) in the global numbers of all tropical cyclones. Anthropogenic warming by the end of the 21st century will likely cause tropical cyclones to have substantially higher rainfall rates than present-day ones, with a model-projected increase of about 10-15% for rainfall rates averaged within about 100 km of the storm center.'

The science also indicates that we will see warming tropical Atlantic SST's, increased upper level wind shear over the Western Atlantic and warmer upper atmospheric temperatures. Warming Atlantic (or oceanic) SST's are conducive for tropical cyclone formation/intensification. The latter two variable are not conducive for storm formation and intensification. So we still have some uncertainties in long term climate projections for the Atlantic basin.


Like I said, believe what you want, I know where I stand.

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QOP = Terrorists
FK = Gay